Coolant - Engine wont warm up - stays cold

[maxhag]

Hey guys.
Got this issue here. I should be able to work this out, but having no luck as yet...

Story: AE71-4AGTE. It's a fresh build in this chassis, but this is a existing engine setup that has been fine for 6 years, in 3 chassis.....

Sorry, but thought it was proberley easier just copying and pasting from the build thread.......


1ST post - After the cars first real drive

- Engine is taking a long time to warm up. Coming home from work tonight (12:30am, minus -4 cold canberra), I let the car warm up for almost 15 minutes before I finished work. When I went to leave, water temp was only 62deg after idleing for 15 minutes (temp on Microtech hand controller). Anyway, after driving, it went up to about 75deg. I turned the heater on. The heater blew COLD air. Not only was it blowing cold air, but the engine water temp dropped dramatically, down to the 50's. I turned the heater off, and it slowly started to creep up again. I only had a few minutes more to drive.
It doesn't sound like the thermostat got a chance to even open. I must have some of the water routing slight wrong, so I will have to have a look at that.....









2nd post: after looking at it

Well , I've just spent 3 hours on this water issue, and now I just have the shits.....
It all looks plumbed ok...... ??????

- Car running at idle, for OVER 20 mins during the day, and temp only just got to 82deg, and wouldn't go any higher than 84deg. (on the Microtech Hand controller) That sensor is on the remote thermostat housing. NO FAN RUNNING
- The aftermarket temp gauge I have, has the sensor on the top radiator pipe, and that is only reading 70deg when the other sensor mentioned above is at 84deg
- Third temp gauge is the stock dash one, which hardly gets off Cold.

I have thoroughly bled the system.
I have checked the thermostat, and it's not stuck open.
Bottom radiator pipe stayed cold until the thermostat housing got to 82deg (as it should), but then would get colder when it started to open and close up again :(
If I turn the heater on, the water temp drops and stays cold.....
All water lines feel hot by touch, except bottom radiator hose. (bottom hose only got a little warm when the thermostat was trying to open)

I should be able to work this out, as I have done many 4age conversions now, but I have never had this issue.....


This is doing my head in, and it's even given me an actual headache!!! Where the hell is the heat going? I cant see how an engine can just idle infinatly (or for even long periods), without cooling??????????????


I have proberley missed something simple, but it's always to get a fresh set of eyes/ears opinion....

Thanks

[maxhag]

My routing for the heater system is as follows:

1. Bypass pipe from top outlet at front of motor,

goes to

2. a tee piece coming off the remote thermostat (to tickle the thermostat and feed too)

goes to

3. one side of heater core (this hose also has a Tee piece to feed the turbo)

comes out other side of heater core and goes to heater tap,

4. from heater tap, goes to water outlet on the back of the head. (this hose has a Tee piece to return from the turbo)......

Should be right............. ??????????????

[Jimmee1990]

Do you have a big alloy radiator? I have an ASI one and my car also struggles to warm up, needs to be left idling for at least 15 mins to get up to temp and drops down to around 75 degrees driving on a cold night. Same issues with the heater too.

[maxhag]

Yeah, it has a brand new alloy radiator (ebay one). The old one which was the same, was destroyed the the Wagon accident.... This never happend with the old setup....
...

[adds]

I have a fairly large alloy rad..dc2 integra I'm pretty sure. I dont run a heater or any of that stuf, and mine (4agte) takes forever to warm up, admitidly I haven't driven it much since my build, but If I let her idle it will take at least 20mins to get warm. Only going by the feel of the bottom rad hose and stock temp gauge in the cluster. I should Probably get a proper temp gauge and see how things go..

what is normal temp anyway, 87? And how long Should it take to get there??

[maxhag]

The thing is, this motor setup never did this before in other chassis I've had it in....
In the old Gold AE86 and the AE71 wagon, car would be up to temp (88deg) within 10 minutes and then the fan would control the temp.

Something is not right. I just cant pu my finger on it.....

If a few of you have this issue aswell, I wopuld suggest sorting it out, as running your engine below temp will cause premature wear to the engine.

[Gunner]

Everything sounds right jojo, but it is possible to over cool the car, next time block half the radiator with cardboard and see if you can get heat into it.

is there anyway you can temp probe the system before it heads back to the radiator? Id be checking the actual head temp with a temp gun or something, and compare it to what is indicated by your various outputs, before making any drastic changes though.

[Lexsmaz]

As has been said it sounds like the New radiator is just to efficient & certainly over cooling is not a good thing for engine efficiency & oil sludging issues etc etc .. I second the blocking off half the radiator & see what happens, you say it didn't do it before but the radiator has been changed since ?? hasn't it ..

[blinded]

If the thermostat is working correctly then shouldn't the radiator be of no issue as unless the engine is up to temp, the water will not be released from the radiator into the system?

[Gunner]

at operating temps the thermostat is very rarely just an open and shut affair, it doesn't get to 90* and snap open. They usually creep open, put one in a pot of water on a stove and you can see it happen.

[maxhag]

Everything sounds right jojo, but it is possible to over cool the car, next time block half the radiator with cardboard and see if you can get heat into it.

is there anyway you can temp probe the system before it heads back to the radiator? Id be checking the actual head temp with a temp gun or something, and compare it to what is indicated by your various outputs, before making any drastic changes though.

Hey man,

I cant see how covering half the radiator would make a differance when the car is just sitting there at idle, NO fan and the thermostat is completly closed. Yey or ney?

I dont understand where the heat generated is going..... ????


The radiator is a new one, BUT IS THE SAME AS THE OLD ONE USED IN THE PAST >>>>>>?????????????


I have just got home from work. It's below 0deg outside...... It is a 15 minute drive home......
I let the car warm up for 10 minutes. Got to 65deg at the remote thermostat, and only about 50deg at the top radiator pipe...... Can anyone explain why the top hose is much colder then the thermostat housing? Surely it should be the other way around?????
After driving home, when I got home, the temp was only 68deg and the thermostat is not even opening.....

Doin my head in....

[maxhag]

at operating temps the thermostat is very rarely just an open and shut affair, it doesn't get to 90* and snap open. They usually creep open, put one in a pot of water on a stove and you can see it happen.

Yeah mate, I am aware of this. This is working as it should. When testing during the day yesterday, the bottom hose was cold untill the remote thermostat housing/actual thermostat got to 82deg and it got slightly warm as it started to open. But, as it opened, it then got colder again and it closed up...

[Gunner]

what temp is your thermostat?

[maxhag]

82deg

[Sam-Q]

If the thermostat is working correctly then shouldn't the radiator be of no issue as unless the engine is up to temp, the water will not be released from the radiator into the system?

I agree with this, it's the whole point of the thermostat. After all people do drive cars in sub-zero temperatures.

[blinded]

Different brand coolant? Or a different ratio mix that may be causing a longer time to warm up? Not sure if that would be a variable from previous builds that may effect the warm up time.

Seems odd that everything was normal on the previous builds...Hmm.

If the thermostat is working id expect it to get to temperature at idle.

When the heater was blowing cold air, did you only just open the heater tap, or was it open the whole time? If it was only just opened, the heater core would have been filled with cold water that would have been released into the system cooling the engine, but also then the core would have been cold and taken time to heat up.

If everything is plumbed up correctly, and the thermostat is working, then I am all it of ideas!

[blinded]

One more thought, do you run an oil cooler?

[Gunner]

we discussed it on fb last night, it needs a hotter thermostat.

[maxhag]

Yes, alex, has a good quality Japanese oil cooler......

[Rice86]

i had similar issues with my previous ae86, had stock jdm radiator and OEM/stock replacement thermostat + oil cooler

just needed a really really good bleed.. and i mean it took about 3 days of bleeding for the water system to get most of the air out.

i lost power, engine would get hot but return water pipe would be cold as fuck..this is after 1 hour and 10 min of driving from work to home i was able to grab and hold the pipe + there wasn't much pressure in the hose.

i dont doubt that you bleed it correctly but a lot of the time its the most stupid things

[maxhag]

Rhys - I fitted another thermostat as you said.... Made ZERO differance with a 90deg thermostat

Sam - yeah, i agree, cars should be able to run at operating temp, regardless of outside weather

Richard - I hear what you are saying, but I am confident the system is well bled. I have done it 3 times already......


I checked my heater routing, and had my hoses to the heater tap the wrong way around compared to a diagram I looked at . I didn't think it would make a differance, and it didn't......

[maxhag]

Iam actually thinking Blinded (Alex) may win the prize....

The Oil cooler.....
The one from this engine setup before, was destroyed in the wagon accident..... The new one I have fitted is a MUCH BETTER quality and is bigger and thicker..... So, its another new addition....

I should have thought of this earlier, but I didn't think the oil cooler would stop heating up at idle. I can see how it would have effect whilst driving, but not while parked and warming up.....

I have just covered the oil cooler and iam going for another test......

[sam92]

As I mentioned on your build thread that I'm having the same issue and have been for weeks. I don't run a oil cooler and mine is still very cold I've changed the thermostat with no difference. I'm running no fan which only makes a difference when stationary, only other thing is I run a fairly big radiator ( sr alloy rad) could this be working too efficiently ? Or maybe as mentioned my system needs a good bleed I haven't even thought of that

[maxhag]

Yeah, ok. hmmmmmmm.....

Ive covered the oil cooler. Made no differance. lol....

[maxhag]

As I mentioned on your build thread that I'm having the same issue and have been for weeks. I don't run a oil cooler and mine is still very cold I've changed the thermostat with no difference. I'm running no fan which only makes a difference when stationary, only other thing is I run a fairly big radiator ( sr alloy rad) could this be working too efficiently ? Or maybe as mentioned my system needs a good bleed I haven't even thought of that

Yeah, I have an alloy radiator too, but, with a closed thermostat, and sitting at idle, it should still heat up in theory......... I can understand it cooling too efficiently whilst driving, but sitting at idle, with no fan activated, it should get hot, as the water is all just flowing thru metal, nothing to aid with cooling etc.....

[Lexsmaz]

Obviously not an easy one to just put your finger on, but the big radiator to my way of thinking still could be the culprit, as I see it when the thermostat is closed water is not running through the radiator but the radiator is still in the equasion in that its hooked up & to my way of thinking its absorbing heat off the cooling system in a convection way ( I think that's the correct word ) like a heat sink, Hot water from the engine is rising to the top of the radiator & being absorbed cooled down by the large volume of water in the radiator & the equasion continues, you don't necessarily have to have water flow to have heat transfer ... It also explains why you said the top of the radiator is colder than around the thermostat housing as its warming up .. I think the oil cooler is not going to be a big factor in that the heat is generated from combustion up high in the motor & that's what the water jackets & cooling system is taking care of & especially as its just sitting there idling & you are not out thrashing it ..

[Gunner]

that's more than possible.

[Lexsmaz]

I would try putting a small radiator in & seeing what happens or if you wanted to even get a pipe just joining the top & bottom hose & run the car at idle that way & see what happens obviously need to hook up up a radiator cap etc & keep a close eye on things ...

[maxhag]

Yeah, Rob, I agree with all the principles you've said there.....
Yeah, the radiator if definatly a heat sink as you said, but I really to struggle to believe that it would absord that much heat from the system.....

[Gunner]

put a standard radiator in it and see what happens.

as I said last night, if it is all set up and bled correctly, there is very little that will stop coming up to op temp. If putting a hotter thermostat in it hasn't changed it, theres only one other real option, and that's the radiator.

unless you have so little timing in it, the engine isn't really working?

[Lexsmaz]

I agree its not a straight forward thing & seems strange but unless you try putting a standard / small genuine radiator in you are never going to really know ..

[Lexsmaz]

Actually retarded timing will generate more heat in the cooling system, not sure if its too noticeable at idle though ..

[blinded]

Fucked if...

Is it possible to have a working thermostat in a corroded/worn housing causing water to still pass through the thermostat and into the radiator? I'm just trying to think of anything haha! Run the car at idle when it is cold with the radiator cap off and see if the water bubbles/moves at all?

[Gunner]

really? have never really run a car with retarded timing so never seen that.

[Lexsmaz]

The other thing I was thinking is to clamp the top hose tight or even remove the hose from the radiator & block it & then start up the car & see what happens keeping a very close eye on things, that way there is no Water / Radiator heat sink & the bottom hose is not going to be problem as the thermostat is stopping much in the way of heat transfer .. fairly easy & quick way of trying things ..

[maxhag]

ok.

1. I will try a stock adm ae86 radiator - I will report the results

2. Cars timing and tune is spot on. Apart from not reaching operating temp, engine runs very well... (186rwkw)

[maxhag]

Fucked if...

Is it possible to have a working thermostat in a corroded/worn housing causing water to still pass through the thermostat and into the radiator? I'm just trying to think of anything haha! Run the car at idle when it is cold with the radiator cap off and see if the water bubbles/moves at all?


Housing is fine. No corrosion....

[Multivalve]

I find it difficult to believe a big radiator can be the culprit. In my Nissan ute with a 7agte my coolant capacity is 10 liters. I have a very large 3 core radiator and my temperature in the motor is controlled by the thermostat at a constant 80c and in the bottom of the radiator I also have a temperature gauge and on that I see between 40c and 60c depending on the outside temperature and running only antifreeze with no water added. I will test the heater valve and ensure that it blocks the water when closed, as I have had a heater valve that did not close the water off and bypassing the thermostat this allowed water to circulate all the time preventing the engine from reaching operating temperature. Have you perhaps drilled the thermostat to get water flowing, or has it still got the standard jiggle pin?

[maxhag]

I find it difficult to believe a big radiator can be the culprit. In my Nissan ute with a 7agte my coolant capacity is 10 liters. I have a very large 3 core radiator and my temperature in the motor is controlled by the thermostat at a constant 80c and in the bottom of the radiator I also have a temperature gauge and on that I see between 40c and 60c depending on the outside temperature and running only antifreeze with no water added. I will test the heater valve and ensure that it blocks the water when closed, as I have had a heater valve that did not close the water off and bypassing the thermostat this allowed water to circulate all the time preventing the engine from reaching operating temperature. Have you perhaps drilled the thermostat to get water flowing, or has it still got the standard jiggle pin?

I totally agree with you Johan....

Personally, I very much doubt it's the radiator too, but I have asked people for help/advice here, and I would be a rude fucktard to then just dis-regard peoples help......


Re; heater tap function
I hear what you are saying about the heater tap, but, in a normal Corolla, even if you have the heater on full, from a cold startup, it will still eventually heat up to temp.....

So, even if the heater tap is not closing, surely it should get warmer than it is.... Also, water is getting a small amount extra heat from the thru the turbo too....

Lets say the heater tap is frucked for example. Even if the water is flowing around those hoses, wouldn't it still get hot? Less water than normal, minimal flow ?????????

[sam92]

After going for a drive is your bottom hose still cold even once the heat has started to rise a little ? I ran my car for ten mins before leaving work this arvo and the temp hadnt even hit 40 on the gauge and when i got home it was just on 40. I left the car running for 20 mins in the garage and with no fan it got up to 82 degrees so it had a total of about 40 mins running. i then felt the bottom rad hose and it was stone cold though the thermostat housing was hot and so was the top of the radiator. i would think that if everything was running fine, that sitting stationary with no air flow would make the temp rise quickly.

[maxhag]

After going for a drive is your bottom hose still cold even once the heat has started to rise a little ? I ran my car for ten mins before leaving work this arvo and the temp hadnt even hit 40 on the gauge and when i got home it was just on 40. I left the car running for 20 mins in the garage and with no fan it got up to 82 degrees so it had a total of about 40 mins running. i then felt the bottom rad hose and it was stone cold though the thermostat housing was hot and so was the top of the radiator. i would think that if everything was running fine, that sitting stationary with no air flow would make the temp rise quickly.

Sam, that EXACTLY describes my issue ...... We def have the same problem.....

As you said, The only 1 time my bottom hose got slightly warm was when the water temp at the remote housing actually got to 80deg, with a 82deg thermostat. Which makes sense, as the thermostat is starting open when it should. That only happened once, during the middle of the day (10deg MAX)

[maxhag]

Sam, is there any way you might be able to post up a pic of your water plumbing?

[rianwest]

The things that I can think of:
- The coolant is mixed at the wrong ratio. It will make little difference but running the wrong ratio will mess up the coolants specific heat capacity (i.e how much energy is required to increase the coolants temp by x degrees).
- The coolant isn't flowing and therefor not heating up uniformly?
- The gauge/sender is faulty (unlikely because you said the hoses were cold)
- The thermostat has somehow been bypassed with the coolant lines for the turbo, or the hoses are routed incorrectly?
- The system has air in it

The heat off the engine at idle has to be going somewhere, the alloy radiator is essentially a big heat sink even when the car isn't moving, but there should be no coolant flowing through it until the engine is hot?

[Lexsmaz]

Can you leave the Radiator cap off whilst it is idling & warming up, if you can leave it off till the engine temp reaches 60 -70 or a bit more in my opinion you haven't got a air lock or lack of flow issue within the motor as if you have air locks it will soon start to show up with the cap off it will start perculating out, it will happen when the temp reaches around 80 or more but not before that though .. But in saying that there is no way in my mind you have incorrect plumbing or an air lock etc as the car would behaving Very poorly after running for the 30 minutes plus you say it runs for & is still coldish & also the cooling system would be physically thumping from boiling spots within the engine cooling system & pumping out water etc, etc .............. My Money is still on the Radiator : )

[Matt]

Is the water pump working?

[maxhag]

Is the water pump working?

I am guessing so Matt. Belt is good, pump turns as normal by hand, no bearing noise or leaks. I havent taken it off. Unless the blades have completly corroded????? which would be strange to happen in 8 months....

[sundee]

Jojo, did you try a stock radiator? I haven't seen you post any results?

This is weird.
I think you may have a combination of problems working against you.

1st - you and Sam have the same issues..
Observation - you both live in parts of this country where night time temps are well below Zero and day time hardly reaches +10'c.

2nd - your (not sure about Sam) running a huge alloy rad
3rd -your running an oil cooler in winter??? Hope it's coupled to a thermostat?
Cold oil and hot oil is bad! .. But cold oil is taking a lot of heat away from your engine.
Observation - this combination in your environment could lead to very low operating temps.

I think that the issue is that the engine is actually not getting up to temp.. (No shit you say)
But really, it's not!
You have changed thermostats with no change.
(82 up to 90) you should have gone the other way.

What you need to do I think is :

1. cover half the radiator with some cardboard (reduce its working area)
2. Remove the darn oil cooler ( it's doing the engine more harm then good during winter)
3. Run a lower temp thermo stat ( see if you can gain uniform temps though out the entire cooling system.)

Question -

1. what coolant/anti freeze are you running and what was the mixing ratio?
2 . Where in the remote thermostat is your microleb temp sensor?
3 . Disregard the dash temp gauge.

If the microleb temp sensor is in the engine side of the thermostat
Then this would lead me even more to believe that your gauges ( microleb and top rad hose) are correct and your engine is really operating at those temps.

[Matt]

Take the thermostat out and i bet there is no difference. Seams like the water is bypassing the thermostat somehow.

And always measure the water temp on what is leaving the engine, not going in from the bottom.

[maxhag]

Nah Matt, its NOT a thermostat issue. Its all been tested. Bottom pipe stays cold until 80deg, then gets warm. Thats what it should do.

JOEL:

1. The oil cooler has a sheet infront of it blocking flow. Sure, it will act as a heat sink, but it should warm up eventually, and it doesn't.
2. Coolant is Penrite green coolant, 50/50
3. The Ecu and hand controller Temp sensor is right where the thermostat is, so that reading, is the exact temp at the thermostat.

Re; combination. I would agree with your combination of things, but only if it was running cold while driving. The fact that this wont warm up idling for some time, leads me to believe its not the main cause here.....


I have thought of a few things, which i will try later today......

[maxhag]

I find it difficult to believe a big radiator can be the culprit. In my Nissan ute with a 7agte my coolant capacity is 10 liters. I have a very large 3 core radiator and my temperature in the motor is controlled by the thermostat at a constant 80c and in the bottom of the radiator I also have a temperature gauge and on that I see between 40c and 60c depending on the outside temperature and running only antifreeze with no water added. I will test the heater valve and ensure that it blocks the water when closed, as I have had a heater valve that did not close the water off and bypassing the thermostat this allowed water to circulate all the time preventing the engine from reaching operating temperature. Have you perhaps drilled the thermostat to get water flowing, or has it still got the standard jiggle pin?


Back to what Johan said.

I am thinking that possibly with a stuffed heater tap PLUS Joels 'combination', could prevent from warming up. The water would still be passing thru the heater core and the turbo, before going back into the waterpump, so to me, I would still think it would eventually warm up after 30 minutes of day driving. :/

What do other people think? Stuffed heater tap?

Either way, I have one here to fit up when I wake up later today. I have checked my hose routing and all looks correct.




EDIT; I then just thought...... If the above was the case, then the heater would blow warm air as least. And it doesn't. Just cold. Switching from hot to cold, seems to make no differance to the air blowing out. I have touched the heater core by hand and its not all that 'hot'.
:/

Someone kill me.

[Lexsmaz]

Its interesting that there seems to be a couple of guys with similar problems .. What coolant capacity do you think the New radiator is compared to say a stockie & physical dimensions too of the new one compared to a stockie .. Re read your first post & its strange that at 70 degrees temp the heater was still blowing cold air, what do the heater hoses feel like in temp ?? same thing happened on my Hilux & I found under the dash there is a deflector type flap inside the heater box that the cable had come off & so the heater & tap was working but no hot air coming into the cabin, maybe a similar problem with your heater ??

[sundee]

I would remove the oil cooler altogether or get your self a thermostat block and plumb it in.
Like I was saying I don't think there is a route cause.. But running low oil temps is causing premature wear to you engine

^ just in regard to point 3.

Is the temp sensor in the thermo housing on the engine side of the thermostat or the radiator side ?

I don't think a heater tap would cause the problem.

Is yours plumbed up like this?

http://www.ae86drivingclub.com.au/dcimages/4/8/5/510609.jpg

[sam92]

I havn't got a photo JoJo and im not at home atm. its a standard water set up though on a sr20de but even though we have different engines surely the problem is the same or very similar. i haven't changed anything lately that would be a factor, i ran my big rad all through summer and it held temp well and im not running an oil cooler. i agree with you the, size of the radiator shouldnt matter a car should still have the capability to reach operating temperature and hold it. im heading home now and am going to look into it a bit more its a pain in the arse problem to have, in most cases its trying to work out ways to cool the car more not try and increase heat.

[Gunner]

end of the day, there is two components in the system that can alter temp, thermostat, and the radiator. And I am going to assume, everyone of you that is having a problem is running a larger than factory alloy radiator?

Instead of looking for some complicated source because it couldn't be so simple, look at the similarities between each of your set ups. All these engines, during winter seem to struggle to reach op temp, and are (from what I can tell from the info given) on average running 10* below desired op temp.

Its not rocket science, its a cooling system.

[Gunner]

oh and the fact that TRP (the guys who played a big part in backyarders 9sec ae82, and have more than a few 300+kw turbo 4a's under their belt) run a half size civic radiator on their set ups says something doesn't it?

and I also find it somewhat laughable that you all believe a big oil cooler is a no no due to over cooling, but the same cant said about a radiator?


Logics guys LOGICS!

[maxhag]

No Rhys, I've decieded to build a rocket instead... :P

[sam92]

I just made progress I hope! I bled my cooling system again I was sure I did it right before but it took 25 minutes for the thermostat to ease open and warm the bottom hose but the top of the rad was boiling before this! I assuming when I changed my thermostat that I've had a pocket of air stuck behind it blocking It ?

[LittleRedSpirit]

Thermostats have a tiny opening to allow the air to get pushed out. Sounds like there was an air lock somewhere though. Remember to turn on your heater while beleeding the cooling system, or you can release air into the system once you think its bled. I had a stock denso ae71 radiator in my car and it ran very cool with that, I even blocked 25% of the core, and Im in qld. If you have an excellent thermofan ducting setup you barely need any air to reach the core anyhow from the outside airstream. I can only imagine how efficient an oversize alloy radiator is in cold temps.

I agree with the routing above, but I thought that it was better to take the heater water from where the pressure builds at the thermostat as its where the water heats first (quick heater), then to release it into the bottom hose (cool water in) area of the system as the air has been cooled in the heater, then the thermostat can meter the incoming water without being supplied midstream with cool water.

[maxhag]

Sam92,
I've just done the same, bled the system again and changed the heater tap..... AND, Yes, air bubbles out after the thermostat had opened..... :/

Heater is now blowing HOT air ;)


After putting the cap on, it would keep a constant 88deg with the fan in use..... Ran it like this for 10 more minutes, and kept constant.
THEN, when I shut off the motor, I could hear boiling for about 30 more sec coming from the turbo water lines ???????

When thermostat/or/ ECU temp sensor was at 88deg, the temp gauge at the top radiator hoe was about 80deg and the factory dash guage was reading just under halfway (ie operating temp)......

Just having lunch now, and letting it cool down, then I will re-check results

[sam92]

I've taken mine for a drive now and it keeping a constant 75-80 degrees and raising up to about 85 and still slowly climbing when sitting stationary ( as expected with no air flow from a fan) I'm letting it cool off now to check again but hopefully that's all it was, if so lesson learnt for me to make sure the thermostat fully opens when bleeding the cooling system.

Its pretty warm in Wagga today but hopefully this has worked and even when it is 0 and below the thermostat should open a lot quicker

[Gunner]

lol

[maxhag]

yeah, same Sam.

Canberra is about 15 today....

[blinded]

Better bust out the shorts

[maxhag]

made little differance Sam92.
you?

[sundee]

When you bleed the water system make sure you have the heater on.

[sam92]

It seemed to have made all the difference for me. The real proof will be taking it for a drive in the morning and seeing how long it takes to reach operations temp from a cold start.

[sam92]

Yeah Joel heater tape was open!

I just cant believe when bleeding it how long it took the thermostat to open and when it did the air came with it. Surely now in the morning the car will heat up quicker.

[sundee]

Air is a piss poor conductor of heat so makes sense if a decent air/vapor lock is happening

[maxhag]

My method today Joel.

Rear wheels of car on road side of gutter, front wheels on driveway, with the front jacked up, so radiator cap is definatly highest point.
Cap off,
Heater on full blast,
Run engine untill bubbles stop and water starts flowing. (20 mins+) Monitoring temps, both at the thermostat housing and the top hose. While warming up, I squeeze the heater hoses etc, to help move any air.

The only change today was that I now have the heater working in the car. Blows hot air now, and cooler air on cold. I did change the heater tap as well as the bleed.

[sam92]

My exact method, I elevated the front of my car also and helped by squeezing the hoses with the heater going flat out.

So you have no improvement on operating temp ? Only the heater has improved ?

[maxhag]

I had it all functioning as it should this afternoon, after the bleed. Engine would hold 88-90deg at idle, with the fan set. This was after the bleed and another10-15 mins of idle.

When I went out for a drive before, about 6 pm. It would have been 0-2deg outside. After 30 mins normal driving, my water temp at thermostat got to 70deg. Oil temp was around 55-60deg. :( :(

So this tells the answer I guess. As Rhys and others said, the radiator and new/better oil cooler must be acting as a very efficient heat sink, and combined with Canberra weather.
I tried 2 radiators from the pile, and they both had corroded badly. So I havent tried another radiator yet.

I totally understand the principles of this, but I just couldn't believe that the generic ebay AE86 radiators could be so differant to one another. As I've said, This engine, and others I've built, have had these radiators, along with many people I know, and never had this occur.....

Well, I still need to try another radiator to confirm this, but I really cant think of anything else.....

[sundee]

Sam - sr20
Jojo - 4ag

Both same issues.

4a doesn't have a bleed point
Sr does.. Assume you used this Sam ?

After bleed - jojo's heater worked but same opp temps as before?
Sam, did u see any change?

[sundee]

Seems like your set Jojo?

[sam92]

I don't use my bleeder point because my radiator sits higher and yes I saw improvement but ill know if it really has done the trick in the morning when I take it for a drive in the cold and see if it warms up. Fingers crossed but I think the bleeding has done the trick

[maxhag]

Sam - sr20
Jojo - 4ag

Both same issues.

4a doesn't have a bleed point
Sr does.. Assume you used this Sam ?

After bleed - jojo's heater worked but same opp temps as before?
Sam, did u see any change?

Yeah Joel, only improvement is that I have heater now....


First, I am also going to bypass the oil cooler, and re-test.
If not "improved", I will pull a radiator out of another car in the yard to try

[LittleRedSpirit]

I don't use my bleeder point because my radiator sits higher and yes I saw improvement but ill know if it really has done the trick in the morning when I take it for a drive in the cold and see if it warms up. Fingers crossed but I think the bleeding has done the trick


You may still find the bleed point will allow air out, it can become trapped. Id tend to assume Nissan put it there for a reason, rather than just waste the effort.

And another thing, imagine how cold the water in the radiator really is when it comes in on the first thermo cycle, its got to be cold if it spends 5-10 minutes inside a massive aluminium heat sync that is travelling at possibly 100klm/hr in a -4 degree air stream, you really do need the thermostat to open slowly.

[nelpd96|]

JoJo, for what it is worth go back to first principles. Forget what the temp sensor/guages are telling you for the moment.

The water gets hot by transferring heat from the block, it is then passed through to the radiator to cool it before going back to the engine.

The flow between the two is controled by the thermostat.

The fan is auxilary cooling to assist in airflow over the radiator and facilitate heat transfer.

So step 1.

What is the block temperature when running? I have an IR temp gun if you need to borrow it. Compare this to one to runs normally like mine.

Step 2.

Once you know roughly what sort of block temp you should have I would run the engine up with the water pump belt off to get the block temp up to where you should expect it to be. Once you are happy with that then hook the belt back on and quickly run it up.

Two things should happen, the thermostat should open and the water temp should be up around the 85-90 mark.

If that checks out you know that you temp measurements are ok and that the block is transferring heat. Go to step 3, if the temp is not what you would expect then calibrate the sensor again in some boiling water, they work through resistance so it is possible that there has been a change in the wiring resistance either though difference earthing for this engine or if something was crushed in the previous accident.

Step 3.

The question then becomes why is the temp dropping back down, this is fundamentally due to the rate of heat transfer between the engine and water is less than that between the water and the radiator.

This situation is brought about because the flow of water is too high, either because the water pump is moving the water too quickly or the thermostat is not regulating the flow of water properly.

Step 4.

Easy way to check is to grab a set of vice grip or a clamp of some description and clamp off the hose that is coming out of the thermostat so induce an artificial restriction. If that works then you know that you thermostat is not slowing the flow of water enough.

I have tomorrow off so if you want me to pop around and have a look let me know.

Cheers
Paul

[maxhag]

AND THE WINNER IS:

ALEX!!!!!!!!!!! (Blinded)

The oil cooler......



Which really makes more sense, as the oil cooler was very differant to the old one, yet the radiators are virtually the same........

It was also the biggest and best quality oil cooler I have even fitted to any car. I simply did not realise how good the unit could perform just acting as a heat sink without flow.....

[maxhag]

After driving around for a while, both normal and the odd giving it a bit, It all seems alright.

*Constant 80-84deg at thermostat with fan set to come on at 90deg
*Temp at top hose is about 10deg cooler than at thermostat across the range.
*Oil is holding a constant 85-90deg.....

[LittleRedSpirit]

Well done. Did you remove it altogether or just thermostatically control it?

[maxhag]

Just removed it completly.....

[Sam-Q]

Sundee is right, cold oil is really bad news for an engine and should be avoided at all times.

[maxhag]

^^^^^ I would hope to think everybody knows that......

[Sam-Q]

For some reason half of that post was missing. What I also said what aftermarket sandwich plates are available with a built in thermostat, put them inline with two lines coming off them and no sump return.

[maxhag]

I think I came prematurely :gah::gah::gah:

More testing was needed when car was cold :/

I just drove home after another cold night...

And........... Problem is certainly NOT fixed

But, making some progress if you could call it that.... lol

So, as usual, I let the car warm up for 10-15mins before I left work.

Readings were:
Temp at thermostat - 84deg
Temp at top hose - 72deg
Oil temp - 55-60deg
Temp on factory dash - Qtr way


As I drove home (normal driving), 2 things happened.
1. Oil temp started to rise
2. Water temp dropped ALOT

By the time I got home (10-15mins later) -
Temp at thermostat - 64deg !!!!!!!!!!!!!!
Temp at top hose - 55deg !!!!!!!!!!!!
Oil temp - 80deg
Temp on factory dash - Pretty much zero reading (COLD)

Oil temp was correct now, but water is not.....




I guess what happened yesterday after I removed the oil cooler, was that the conditions were just right, daytime, engine was used throughout the day etc, that the water absorbed just enough more heat from the hotter oil, to make it appear it was all working somewhat normal.


All comes back to the Radiator as discussed.......

[nelpd96|]

JoJo, did you read my post. Try restricting the water flow first it is easier than swapping radiators.

[Multivalve]

Just read throuh this whole thread again. You have a 4 agte so I assume on the turbo you have watercooling, if that is the case how is the route of your waterlines to and from the turbo? I had mine tapped in on the heater hoses and never had problems with engine temprature but at a stage i thought this hot water leaving the turbo and entering the block again is not a cool idea so I routed my return from the turbo direct to the radiator and when driven brisk taking it high up in the rev range throug the gears I had massive engine temprature drop. I then routed the lines back to the heater setup and temprature spikes were all gone. This might be your problem. I assume from your replys that the oil cooler must be massive, in the region of a 30 row cooler. I had oil temprature troubles, installed a 15 row e bay oil cooler, the blue one and my oil now stays at a constant 80c

[maxhag]

Johan.

Turbo water cooling:

1. Outlet hose from back of head goes to the IN (front) on the heater tap. This bit of hose has a Tee piece, which goes to the turbo as water IN
I have done it like that, so the turbo always has water flowing thru it, regardless of heater tap operation

2. Lines and fittings for the turbo's water are DASH -6 (6mm)

3. Water comes OUT of turbo, and routes back to a hose with a Tee piece, that feeds back to the Remote thermostat housing (After all heater operation), which passes past the thermostat as the waterpump sucks it back into the head....


Yes, it means the turbo has constant flow, thru -6 fittings and the turbo it'self. I did think that maybe it's too much flow, but this has worked fine in the past.... ????

I have had engines I the past with no heater parts etc, and just had the rear water outlet feed only a turbo instead.. with no issues

[maxhag]

Yeah, the oil cooler was a good quality Japanese one. Not only a large cooler, but it is twin core too....

[rianwest]

Johan.

Turbo water cooling:

1. Outlet hose from back of head goes to the IN (front) on the heater tap. This bit of hose has a Tee piece, which goes to the turbo as water IN
I have done it like that, so the turbo always has water flowing thru it, regardless of heater tap operation

2. Lines and fittings for the turbo's water are DASH -6 (6mm)

3. Water comes OUT of turbo, and routes back to a hose with a Tee piece, that feeds back to the Remote thermostat housing (After all heater operation), which passes past the thermostat as the waterpump sucks it back into the head....


Yes, it means the turbo has constant flow, thru -6 fittings and the turbo it'self. I did think that maybe it's too much flow, but this has worked fine in the past.... ????

I have had engines I the past with no heater parts etc, and just had the rear water outlet feed only a turbo instead.. with no issues

So you are feeding the hot coolant from the turbo straight into the thermostat housing? Would this not open the thermostat prematurely as the coolant from the turbo will be hotter than the rest of the cooling system?

[sundee]

So, as usual, I let the car warm up for 10-15mins before I left work.

Readings were:
Temp at thermostat - 84deg
Temp at top hose - 72deg
Oil temp - 55-60deg
Temp on factory dash - Qtr way


As I drove home (normal driving), 2 things happened.
1. Oil temp started to rise
2. Water temp dropped ALOT

By the time I got home (10-15mins later) -
Temp at thermostat - 64deg !!!!!!!!!!!!!!
Temp at top hose - 55deg !!!!!!!!!!!!
Oil temp - 80deg
Temp on factory dash - Pretty much zero reading (COLD)

Oil temp was correct now, but water is not.....

....

Are those temps with the oil cooler removed?
What were your oil temps with the cooler plumbed in eg. During a night drive home from work?

...I see what Paul is saying... But I don't think that the temp at the thermostat compared to the actual temp inside the engine would be that much different once it has stabilised.
I may be wrong.. Just thinking aloud

[maxhag]

^^ Yes Joel, Above is with the OIL COOLER REMOVED




Just got home from work......

I have put cardboard infront of the radiator...

Temps were better, but still not right (78deg at thermostat when got home), and still took a very long time to get there....

[maxhag]

So you are feeding the hot coolant from the turbo straight into the thermostat housing? Would this not open the thermostat prematurely as the coolant from the turbo will be hotter than the rest of the cooling system?

Yes and no.... The return from the turbo goes to a tee piece on the outgoing heater lines..... So the hose bringing the water from the turbo and heater system into the remote thermostat housing is already mixed before it hits the themostat housing

[Gunner]

switch the hoses around jojo, Rian is onto something.

[maxhag]

Around?

[maxhag]

either way, the bottom rad pipe is cold untill 82deg......

[maxhag]

Here is my water routing. Hopefully my shithouse drawing skills dont make it too confusing :P


http://www.ae86drivingclub.com.au/dcimages/1/1/1/510648.jpg (http://s150.photobucket.com/user/maxhag/media/waterrouting_zps4997a5f9.jpg.html)

[Multivalve]

I had the same size waterlines through the turbo in the same place as I see in your drawing, that gave me the temprature spikes. I then took the return from the turbo and brazed a suitable fitting into the large pipe at the back of the water pump, and my spikes were gone. If you are using the water heating in the throttle body you can also see that one of the waterlines enter the pipe at the back of the waterpump and t into this line. Waterflow from turbo will then be routed straight back into the block and not into the thermostat housing and I think that will solve your trouble.

[maxhag]

I really cant see how that would make any differance Johan.......
It would actually create a bypass of the thermostat, which I see no point doing, as the thermostat is there to 'monitor' this water........... We have already established that the bottom radiator hose is cold untill 80deg, so there is nothing wrong with the thermostat function......

Please correct me if I am wrong......

[meadan]

Just out of curiosity, why is your microtech temp sensor mounted in the thermostat housing?

I understand that it worked well before, and it shouldnt make much difference at all...but I liked to mount at least one temp sensor in the back of the head water outlet. I ran one at the front and one at the rear, to give a proper idea of engine temp. This is where the factory sensors are also.

The way I see it, the whole external water setup acts as a radiator to a minimal degree, especially seeing you live in ridiculous cold conditions compared to most.

This probably doesnt help, but im curious about peoples opinions about temp sender positioning.

Other than that, it looks like you have it setup well, how does the temp go when driving enthusiastically? Like with air running through the engine bay but driving hard to get the engine hot?

[maxhag]

My outllet at the back of head is not standard. It is just a hose outlet..... No provision for a sensor....
So, I figured to mount it to the thermostat housing giving a exact thermostat/incoming engine water temp..... Then, having the gauge sensor on the top hose, can monitor water temps quite well..

[Multivalve]

Like Rian said I also think if the water return from the turbo go into the thermostat housing it may open the thermostat whilst the rest of the engine is not yet at the same temprature. The turbo will heat the water alot quicker than the water in the block and head, having this little bit of hot water back into the block will help the engine reach operating temprature and then the thermostat will control it. From coldstart the exhaust gas heat the turbo and the water in the turbo housing rather quickly and the engine will take longer to teach the same temprature. I hope you understand my thinking. I'm trying my best to help you solve this issue. I don't find anything wrong with your temprature sender placement, it makes sense the way you have it but I'll swap the microtech and gauage around as the microtech controll the fuel based on water temprature and will be better in my opinion to see temprature from the head rather than temprature from the radiator entering the engine

[maxhag]

How do you explain the bottom radiator pipe being cold?
That pretty much rules out any theory on the thermostat opening prematurely......

[nelpd96|]

How do you figure that, the water is drawn from the radiator through that bottom pipe into the water pump. Of course it is going to be cooler than the top pipe. It is very simple, the engine get hot the water cools it. If the water is not getting hot then it is not staying in the block long enough, or the block is not getting hot. Those are your only options, there might be a few reasons why it is doing one of those things but I can tell you now you will be able to trace the problem to one of them.

[Seventy]

Still going to try a standard radiator? Remember guys the same setup was fine in other cars... Did you actually drive much in winter with this setup in the other cars?

[maxhag]

How do you figure that, the water is drawn from the radiator through that bottom pipe into the water pump. Of course it is going to be cooler than the top pipe. It is very simple, the engine get hot the water cools it. If the water is not getting hot then it is not staying in the block long enough, or the block is not getting hot. Those are your only options, there might be a few reasons why it is doing one of those things but I can tell you now you will be able to trace the problem to one of them.

I totally agree. Tracing it is my problem...... :/ You probably know this engine better than anyone here, well proven engine. All the years, driving to the hillclimb on the Icy cold mornings, never the issue. Nothing really has changed. If the fix IS NOT the radiator, then something very strange is happening :o
If you have any free time and you're in the area, feel free to drop past. Any help is always appreciated.....
Thanks Paul



SEVENTY: Yeah, changing the radiator is still the plan, I actually picked up a AE71 standard radiator today from one I am wrecking, which looks good. No bent fins at all...... I will be trying that

[nelpd96|]

I will run mine up to temp tomorrow and get a block temp on the IR gun so we have a reference point. I still think that you should just clamp off the water return line to the top of the radiator, it will give you a very quick idea of what is going on.

I have got and engineering job on tomorrow arvo but should be free on Thursday I think I will give you a buzz and see how you are getting on.

Cheers
Paul

P.S. Keep and eye out for a neat KE70/ AE71 to put my running gear in while I sort out my shell.

[maxhag]

I got a white ke70 you can have cheap ($250), might not be as 'neat' as your after tho.... Very little rust tho....

[nelpd96|]

I will have a look when I come over.

[maxhag]

OK. PROBLEM IS FINALLY SOLVED!!!

After much driving me crazy, I have found the problem.........

Thermostat housing was corroded..... Water was obviously bypassing around the thermostat.......
I changed the housing, and BAM, system is running perfect....

keeps water constantly in the 80's and oil 10deg higher than the water.......
Car warms up obviously quicker too

The problem was mentioned by someone earlier on and it is indeed the issue.... (just looked, it was Alex AGAIN!)


Certainly was not the radiator for those who insisted it was......
Nothing to do with the Canberra climate either......




Thanks to all those who had their input, always appreciated.

Jojo

[maxhag]

Well, there it is, Once again (second time lol), Alex had the CORRECT answer/s.....





Fucked if...

Is it possible to have a working thermostat in a corroded/worn housing causing water to still pass through the thermostat and into the radiator? I'm just trying to think of anything haha! Run the car at idle when it is cold with the radiator cap off and see if the water bubbles/moves at all?

[evil86]

Enjoyable read, happy that you fixed your problems JoJo. Time to tackle my water problems:)