4AC thermostat - needed?

[Driftspec]

Hi guys,

Long story short, the old 4AC in my car has been intermittently overheating on longer drives. Not badly, but sometimes enough to get steam coming out of the overflow. Radiator seems fine, water pump and fan are working, the only thing I (and others who I've talked about it to) think that the thermostat is acting up.

My question is, can I rip the sucker out and just let the water flow all the time? Or should I just replace it as soon as possible?

Thanks lads.

[Matt-AE86]

If you are planning on removing the motor sometime soon, just remove the thermostat.

If you are planning on using the 4AC for a while longer. Replace the thermostat and remplace the water pump if it hasn't been replaced recently. Even if you say it "works".

[Driftspec]

I don't know if it work for sure, but there isn't any strange noises that suggest there is anything out of the ordinary.

I will be running it for a while yet, so if it needs to be replaced I might as well pull it out and test it, rather than just rip it out and be done with it.

I also need to identify my radiator, I'm a little confused as I always thought it was a standard, but Callum (deleta) looked at it one day and said it was a Skyline rad. So I will have to grab some pics and post them up, and use the brain trust here to help out. It has a radiator places sticker on it, so I know its 2nd hand or reconditioned, at the least. I'll try and grab pics tomorrow, if I get time :|

[rthy]

is it fwd or rwd? rwd dont have thermo stats?

if u let the water flow that car wont keep operating temp, so id repalce it.
just did mine cost $14 @ autoone

[Driftspec]

RWD. 4AC in an ADM AE86.

The engine has always run warm, so my line of thinking is that letting it run through isn't necessarily a bad thing. When I get time I will have to test it, and replace. Thanks for the price, hopefully its just that. If not... then its the pump or radiator. Woot.

[Golberg]

Other thing to look at is whether your radiator is blocked up at all.

And for rthy up there, just about all cars have thermostats, FWD or RWD. Its integrated into the pump housing on a RWD setup.

[rthy]

hmmm didnt find one when i took apart my old rwd 4ac water pump?
any got pics of what it should look like?

edit: nvm found it
http://www.rollaclub.com/board/?showtopic=19896

i guess my old ae71 4ac never had a thermo stat, i guess thats why it had problems getting to operating temp lols

[Golberg]

Something like this:
http://www.partsplaza-admin.co.uk/PartImages/100458001.JPG

Its behind the bottom pump inlet, somebody may have got to it first though.

[Jonny Rochester]

If you run no thermostate, or if it is stuck open, the engine can overheat on a longer drive.

[Driftspec]

Thats what is happening Jonny, short drives are fine, but longer drives it gets hot. Being a 4AC, it doesn't lose any performance, but I think it will be staying in the car for a while now so I need it working well, to prevent other issues.

The radiator was something thats probably worth replacing anyway, being fairly old. Like I said, I will need some help (when I get pics) to try and suss out what I have. Got prices and pics for replacement R32 and R33 rads today, if that is what I have already that would make a nice easy replacement. If not, might have to suss something else out.

[Jonny Rochester]

Take the thermostate out, put it in a cup. Pour hot boiling water over it, watch it open. Keep watching as it cools down and closes again. It it does not open and close, get a new one which I am sure you can afford.

[H8CHIR6KU]

i wouldnt bother just going and buying a new radiator. why don't you just get it serviced instead?

if you get it serviced and they say its rooted, then get a new one. otherwise save yourself a couple of hundred and get it serviced.

if its ok on short drives but overheats on long drives it would more than likely be a blocked radiator or your fan is not working. if you still have the viscous fan you can check to see if it still works.

you can check it easily. first way to see if it is working is simple, when the car is at operating temp for a while, fan should stop moving as soon as you turn the motor off. the second is, when the engine is running while hot use a stick or pole and try to stop the fan by just touching the edge of the blade. if the fan stops easily its rooted.

[ke70dave]

yer i woudldnt do anything harsh yet.....and whatever you do do not run with no thermostat, they are there for a reason. cold engines are just as dangerous as overheated ones.

start of by draining your cooling system, and flushing it out. pull out the thermo stat, and then bolt it back together and stick a hose on the outlet on your head, and flush out all the crap.

then do what has been suggested by putting the thermostat in hot water and testing that it opens and closes, if it looks dodgy i would be inclined to get a new one anyway, they are like $20.

next take OUT your radiator, and flush it properly. hold your hand on the bottom outlet, fill it up with water, and then let it rush out. keep doin things untill you see no noticable change.

next do exactly the same thing but with the radiator UPSIDE DOWN, holding the top outlet (which is not closest to the ground) filling it up, and letting the water flush out.

it might also be worth taking off the water pump (not sure if you need to do this to take out thermostat..) and checking to make sure that the impella inside isnt corroded or anything.

once your certain its all nice and flushed out, put it all back together with some nice new green coolant from poopercheap and ensure that its all bleed properly.

just a note that the cooling fan does nothing once the car is up to speed so if the car is overheating while its driving then the fan has nothing to do with it.

it may also pay to check your ignition timing and possibly give your carby a bit of a clean with some carby cleaner, lean mixture or too advanced will lead to heat. its a long shot, but keep it in mind if you dont have any success once youve cleaned the cooling system and/or changed the thermostat.

[H8CHIR6KU]

yeah as above is pretty good points. the only thing i would change though is to get your radiator serviced by a proffesional. while "blowing it out with a hose" seems ok it is not garaunteed to work. remove it, take it to like natrad and have them rod it out. it is the only way to guaranty its fully unblocked without buying a new one.

the fan will work at moderate and slow speeds. esp at low speeds and when coming to a stop. you run a car without a fan and see how long you go without overheating. it may not happen in 4-5 min of driving but go 10-15 and i will guarantee it will get hot (except freeway driving). these days i seem to see a lot of toyotas and land rovers that have viscous fans that just don't work, and its always the same complaints. gets hot just driving around or sitting in traffic.

[ke70dave]

yeah as above is pretty good points. the only thing i would change though is to get your radiator serviced by a proffesional. while "blowing it out with a hose" seems ok it is not garaunteed to work. remove it, take it to like natrad and have them rod it out. it is the only way to guaranty its fully unblocked without buying a new one.

the use of the use i was referring to was cleaning out the cooling passages in the block/head.

using a hose on the raidator it self will not do much as you say, you gota flush it out.

i dunno about "servicing" radiators, sounds expensive for something that you may not need. and that a flush will do. unless of course your radiator is actually rooted and rusted up, but i haven't seen one like that.

[Driftspec]

The clutch fan (attached to the engine) still spins quite happily, although I will chech it when I get a chance.

Thanks for you replies guys. Thermostat should be easy and cheap to replace. Thanks for your post too dave, I know have a bit of an attack plan to try and get it sorted, once I get some time. I've never had to do this before, so guess who gets to learn a bit again :)

Cheers guys.

[H8CHIR6KU]

i dunno about "servicing" radiators, sounds expensive for something that you may not need. and that a flush will do. unless of course your radiator is actually rooted and rusted up, but i haven't seen one like that.

i do know about radiator servicing and it is good value for money.

just over $100 gets you a rodded out radiator that has been resealed and pressure tested. guaranteed to work efficiently when you put it in. if its fucked then you need to get a new radiator.

just think long drive or short drive, when your radiator is 40% blocked its like driving with half sized radiator. it doesnt take long to block a new radiator either, especially with old iron blocked motors.

i see this shit alot and blocked radiator is definetely something that should not be ruled out. obviously do the easy first. i.e thermostat.

but just to let you know that you will have trouble bleeding the car out if your radiator is blocked

[Bobomacho]

nobody here has made any mention of a faulty radiator cap
if its fucked it won't hold any pressure and just spit it into the overflow

[Sam-Q]

rthy: what do you mean rwd dont have thermostats??? everything has one.

H8CHIR6KU: you have some good points but for $100 it might be worth just chucking a hyundai one in.

bobomacho: good point

[Driftspec]

It doesn't always spit into the overflow, in fact only twice in the last week and a half has it been hot enough for it to spit steam into the overflow. Water level stays the same between drives, apart from when it heats up bad, and then it goes down.

Thanks for the heads up H8CHIR6KU, I've noticed the colour of the water is turning more brown, which isn't a good sign. Half tempted to take it down to a radiator place, and get them to look at it, flush it out, replace the thermostat (if need be) and check the radiator out. I don't know if I will get a chance to do it myself, so getting someone to check it out (and hopefully sort it out) sounds like a decent option.

Cheers.

[rthy]

rthy: what do you mean rwd dont have thermostats??? everything has one.

my 1st 4ac with rwd thermo didnt have one so i assume they all didnt have one lol

[Sam-Q]

oh well simple mistake, particually if it doesnt look like its been opened

[H8CHIR6KU]

Thanks for the heads up H8CHIR6KU, I've noticed the colour of the water is turning more brown, which isn't a good sign. Half tempted to take it down to a radiator place, and get them to look at it, flush it out, replace the thermostat (if need be) and check the radiator out. I don't know if I will get a chance to do it myself, so getting someone to check it out (and hopefully sort it out) sounds like a decent option.

Cheers.

sounds like there is stuff all glycol in your cooling system. most of the time the reason the coolant turns brown is that there is low coolant% and as it heats up it loosens scale (shit and rust) from inside the block and flows it thru the rest of the system. in this case you will need to either replace or service your radiator, and completely flush the cooling system anyway. more than likely all that shit from your block will now be stuck in your radiator.

if you dont flush it when doing your radiator it is just gonna end back up in your radiator.

i know you haven't mentioned it but just in case, i wouldnt recommend using a second hand radiator unless you need to replace the one you have. even then i would have it serviced before you put it in. i have used second handies before only to give a worse result. after all you cant see inside the second hand one