car running too cold what the hell

[slider4life]

hey guys a little while back i had my bt 20v over heating i have sence done research and sam q has helped me out on how to run the cooling system, i have run my cooling system exactly the way sam q has said and also ran the bypass from the top of the water pump to the top rad hose, my issue is around town and at idle it sits at a perfect temp of about 80 deg, as soon as i start to drive or around town it drops to 70 odd deg, but if i hit the high way she will drop to 45 to 50 deg which is shit. now i have a koya alloy rad, ive checked the thermostat and replaced that with a new one no issue there.i have sence put a welsh plug in the top rad hose with a ten mil hole, this has helped as it sits a 80 deg for about 30min but then it starts to drop and eventually and hits 45 deg. i have just purchased an alloy pully kit with an under driven water pump pully, do you think this will help as im thinking the cars water pump is spinning too fast as my car sits on 4000rpm at 100klm as i have 4.7 diff gears?????
any ideas on this

[DOG the rolla hunter]

is the temp gauge taking reading in the right spot???. all symptoms suggest a stuck open thermostat but you did that??maybe radiator is too efficent and when the thermostat opens it gets a rush of cold water. maybe a hotter thermostat will help

[ke70dave]

damn 45 is cold as!!!

you sure your temp guage works well?

where is your temp guage sender located?

[slider4life]

yeah its a new gauge vdo and its picking its temp from the rear of the head on the passenger side were the top rad hose is ment to come out of, the prob is at idle it sits at a perfect temp of 80 deg if i put a hotter thermostat in wont it over heat at idle or is this wrong????

[DOG the rolla hunter]

sounds thermostat man. might be worth checking. did you use genuine one? im mechanic and refuse to use aftermarket because ive been bitten too many times.either dont open or stay open or too slow to react

[slider4life]

yeah she not genuine as i work at autobarn :). ill order one from toyota to cross this one out do i ask for anything particular or just a thermostat for an ae111 levin its a black top 20v

[DOG the rolla hunter]

just get a standard one.even if it dont fix it its piece of mind and no fuck ups. i bought one for 7afe on weekend 35$ with o ring, why fuck around with the other shit? not worth the worry. im confident it will help if not let me know ,keen to help and find cause

[slider4life]

thanks mate yeah ill let you know how it goes, hopefully this pully kit will turn up on friday and ill see whatbthat dose too

[DOG the rolla hunter]

dont think slowing water pump will help,temperature is controlled by thermostat.do one repair at a time to eliminate one or the other.

[slider4life]

yeah but if i travel at 60 70klm it sits at a good temp about 70 75 its when i start revin her above 3500 rpm it starts to drop alot, ill do one at a time and let you know what happens

[blair]

Mine does this also. Not as harsh (45deg is barely luke warm baha!)

But yeh same deal, regular driving doesnt budge over 80, but mountain runs / high revs etc the water goes down to ~60 at times...

And i got a new thermostat and water pump a while ago...

I do run a Massive ass radiator... but i still thought the thermostat would be able to block off/circulate the water to keep it at 80.

[ke70dave]

you could do a bit of experimenting,

cover half your radiator with a peice of cardboard, see what happends.

[slider4life]

done that i have a ten row oil cooler in front of my rad i have both my hid balasts mounted on my rad and i covered half the rad that was left with card board and i run a welsh plug in the top of the rad hose with a ten mill hole and it still dropped temp it took longer about an hour but it did drop to the 55 deg mark

[Sam-Q]

did you put in a single stage/non bypass thermostat though?

edit: now that I think about it that can only make it run too hot not too cold.

[DOG the rolla hunter]

ahhh good point^^^^^^^^^^^^^^^^^

[slider4life]

i doubt an autobarn thermostate is one of those to be honest i dont know what that is???? do you know what the part number is i have to order??????

edit:bypass is the hole in the side it dose have one of those in it.

[stx-16]

you could do a bit of experimenting,

cover half your radiator with a peice of cardboard, see what happends.

mine is like this all the time but you have to change cardboard after it rains or it will get moldy lol

[driftke70]

just drive harder?

[Stain]

lol ^

Sounds like the temp sensor is taking the reading from the wrong spot... ie; the cold water coming out of the rad rather than the hot water going back in.

[wntdae86]

lol my car sits at 3500 rpm at 100km and still hot ....

i would say to pull your fan out and see what happens
then mayb your radi is to good for such a lill motor

[H8CHIR6KU]

temp sensor really should be in the top hose outlet. i also have the same thing happen with my engine temop sensor which is at the back of the head on my 20v. while my guage reads 80deg from the guage sender in the top hose outlet the one at the back of the head reads about 50deg. i kno wthis because my ecu tells me this.

i was using an underdrive pulley and it made the car overheat sitting at idle cause the water isnt flowing enough. i also running a big arse radiator too. i personnaly would prefer to run the smaller standard pulley

how are your thermofans setup? are they always on?

something else to think about... alot of cars run a seperate guage sender in a different spot on the car than the coolant temp sensor. most are setup to have your guage read in the hotest part of the system while the ecu sensor is more setup to read what the engine is actually operating at

[Sam-Q]

lol my car sits at 3500 rpm at 100km and still hot ....

i would say to pull your fan out and see what happens
then mayb your radi is to good for such a lill motor

impossible, thats what the thermostat is there for.


H8CHIR6KU: there shouldn't be much different between the rear port and the top outlet with a bypass type system. There is only one large diameter non cooling related channel between the two.

[H8CHIR6KU]

id presume the cold water flowing in is the reason for this. over efficient rad creates different readings from cool water flow to the back of the block to hotter water passing thru my guage temp sender

even still on a stock 4age ae86 the guage temp sensor is in the top hose outlet while the cooling temp sensor is at the back of the head. it would make sense to set it up like this

[reecegze]

Mines very similar in setup, i run a oil cooler front mounted with koyo radiator and it likes to run cold.

Where is the best place for the water temp sender to be fitted ? ive got mine on the top radiator hose and my temps never get above 80 with a 7" thermo on constant. On the hwy it gets to about 72ish. Should i be reading it from the bottom hose as when i fitted it, i didnt really think of position

[H8CHIR6KU]

i think the top hose is best

[AE092]

Have the exact same issue: around town, the temp will sit just below the middle. Go on the highway for 5mins or longer and it'll sit a little bit pass the "C". Back in town and it'll go and idle ok. Big alloy radiator as well.

[slider4life]

sounds like the big rad is to blame my thermo dont come on until it hits 90deg i only ever seen it come on once and that was when it was gettin tuned it then turns off at 82deg via the haltec e8, ill see what this pully kit dose if it dosent over heat at idle i think i will be sweet.

[redsprinter]

lol ^

Sounds like the temp sensor is taking the reading from the wrong spot... ie; the cold water coming out of the rad rather than the hot water going back in.

^^ sounds like hes onto something

[ke70dave]

the temp guage sender should be on the "inside loop" of the cooling system.

so when the thermostat is closed the water that is swimming around your engine is what should be read on the temp guage.

who cares what temp is in the radiator, thats not the part we are trying to stop overheating.

you shouldnt really see any dramatic change in water temp as the thermostat opens and closes, as the thermostats job is to regulate the temp.

i am unfamiliar with the 20V water system, but on the 16V my temp guage sender is right next to the thermostat on the "hot" side (the engine side).

one other test, when the water is sitting at the appartent 45degrees, quickly pull over and put your hand on the radiator, if it is that cold then you should be able to keep your hand there for a while...

[H8CHIR6KU]

the temp guage sender should be on the "inside loop" of the cooling system.

so when the thermostat is closed the water that is swimming around your engine is what should be read on the temp guage.

who cares what temp is in the radiator, thats not the part we are trying to stop overheating.

you shouldnt really see any dramatic change in water temp as the thermostat opens and closes, as the thermostats job is to regulate the temp.

i am unfamiliar with the 20V water system, but on the 16V my temp guage sender is right next to the thermostat on the "hot" side (the engine side).

one other test, when the water is sitting at the appartent 45degrees, quickly pull over and put your hand on the radiator, if it is that cold then you should be able to keep your hand there for a while...

most cars have the guage on the water side going into the radiator because theoretically this will be the hotest coolant in the system. i take it your running your 16v from a fwd setup

[wntdae86]

the temp sender should be on the flow side so on the hot side .....

[slider4life]

well guys i tryed the genuine thermostate it made no diffrence so i can cross that off.

[slider4life]

and that im aware of this is how my cooling system works thanks to sam q website

The cold water leaves the radiator and enters the back of the water pump, it is pushed through the block, through the center and exhaust side of the head, is bypassed at the back of the head to divert the flow down the inlet port coolant channel and out to the radiator.

So in summary for the modified cooling path:

- Bottom of radiator cold water out
- Water pump
- Engine block
- exhaust side of head
- Head inlet ports channel (passage above inlet ports)
- Top radiator hose and radiator

[H8CHIR6KU]

and that im aware of this is how my cooling system works thanks to sam q website

The cold water leaves the radiator and enters the back of the water pump, it is pushed through the block, through the center and exhaust side of the head, is bypassed at the back of the head to divert the flow down the inlet port coolant channel and out to the radiator.

So in summary for the modified cooling path:

- Bottom of radiator cold water out
- Water pump
- Engine block
- exhaust side of head
- Head inlet ports channel (passage above inlet ports)
- Top radiator hose and radiator

so from that summary i would try having the temp sender for the guage in the top hose outlet as that would be reading the hotest part of the system

[dtour]

i have the same issue, i used the rschita kit so my 20v is setup like a bigport, ie sensor for ecu in back of head and dash sensor in top radiator pipe, i also have a fat alloy rad.
When sitting in traffic temps climb to 85 thermos turn on temps go back down, start driving temps fall to roughly 65 all these reading come from the back of the head. so... I dunooo...
So what is the stock temp the thermostat opens?

[H8CHIR6KU]

from memory is 82 degrees. i would say with your car your cooling it too early. most thermo fans on street cars come on around the 96 degree mark, some a bit more. if its too cold your just going to play havoc with your thermostat opening and closing all the time

[R&D Mechanical]

+1 to what ken said, i had the same thing, 80 degree on the standed water outlet sender for the gauge next to the top hose and, about 60 degrees at the back of the head for the coolant temp sensor (getting the readings from the ECU). I would say its always the best way to have the gauge on the hottest side to be safe. when my guage (speco) goes to 100 i know its still safe, even 120 is good but i would stop as its the end of the gauge and you dont know what it could be after that.

[ke70dave]

so assuming you have a standard cooling system.

where is the sender for the guage on a standard 20V?

[H8CHIR6KU]

+1 to what ken said

by ken do you mean me? cause im aaron. like the 3rd person called me ken in 2 days, or was it kent????

[H8CHIR6KU]

so assuming you have a standard cooling system.

where is the sender for the guage on a standard 20V?

thats like comparing a fwd bigport motor and a rwd bigport motor. fwd setup is near the thermostat while rwd is in the top hose outlet.

but the fwd motor isnt running in fwd configuration and the cooling system isnt standard anymore so is kind of irrelevent how it was

[ke70dave]

hmmm not sure my question came across the way it was intended.

how does the OP's cooling system compare to a standard 20V setup.

and on a standard 20V setup where is the temp guage sender located.

[Sam-Q]

ok slider I must of already seen it but can you re post your pictures of what you have on here?

[slider4life]

here are a couple of pics with were everything runs dont laugh at my paint skill as i never used it before

[Hachi_Tom]

Its bad to run too cold water? i knew it would be bad if oil but water?
explain why if possible please?

[Sam-Q]

you mean is it bad if the engine is too cool? rapid block wear will result

[Sam-Q]

here are a couple of pics with were everything runs dont laugh at my paint skill as i never used it before

well your heater is hooked up right, but that shouldn't cause it to run too cool. It should be from the back of the pump to the heater core, out the other side of the heater core to the flow controller and to the back of the head.

[slider4life]

well guys i just installed the under driven water pump pully today and i just took it for a run it sits at 90 deg at idle and run it down the high way and it sits at 80 deg. if i sit at idle for abit on the high way it sits at 90deg i nail it and bash throught he gears from 1st to 3rd to 120klm it drops to 65 deg but once i back off and sit on a hundred it climbs pretty quick to 80deg. only thing im worried about is it is a really cold night tonight, if i get a hot day it may over heat. but on the other hand the thermos havent come on as i havent hit 96 deg yet. ill let you know how i go, also i have removed the walsh plug from the top rad hose so fingers crossed its all sweet.

sam q yes that is how the heater runs i think on the standard tap which one goes were, or i can trace it to the fire wall left or right goes to which tap side then to block or back of water pump??

[Sam-Q]

the heater tap is meant to go off the back of the heater to the heater core