Overheating problem!! Please help

[fairladyzz]

Ok, it's a 1990 twin turbo, it's been overheating since I bought it 2 months ago.
This is what I have done to try to fix it.
1. (2) coolant flushes
2. Koyo aluminum rad
3. 14" electric fan
4. New rad hoses
5. Thermostat

after all this it just takes longer to overheat, what else can it be please advise I can't drive very far with my car.

[ffrpwner]

one thing....ive heard the stock fan works better then electric fans...

ummm i dont know if this will efect anything but wat oil do you use maybe if its not thick enough its not protecting the internals enough causing more heat.....

idk im trying to help...hopefully more people will post ps i like ur front bumper same one ive got on my tt =)

[robomatic12]

You are burping the coolant system properly? You must get rid of all the air bubbles to get proper cooling. Have you verified the stock gauge accuracy? What do you mean by overheating, gauge going to hot or steam coming from under hood? Did you verify the thermostat with a thermometer and a boiling pot of water before installing? Is it OEM?

On the worse end, it could be a blown headgasket, the hot combustion gases making their way into the coolant, overheating very quickly.

[Z32TT]

Check your oil see if its milky if so then headgasket is bad, honestly though i think its your fan how many cfm does that one push? stock clutch fan is the best to stay with period.

[legion]

He bought the electric fan to try and fix the overheating problem. Therefore it was overheating before switch to the electric fan. Meaning it's not the root of the problem.

[fairladyzz]

I don't think it's a blown head gasket because it doesn't smoke from the exhaust, and the temp has been tested with an external thermomer, it's been properly burped, umm the only thing i might thunk it is the coolant temp sensor?? I just changed the oil 2 times one to lift the lifters with ATF and then reflushed..I've done almos everything.

Oh thanks for the bumper comment, but since it's broken I might get the jdm bumper.

[fairladyzz]

Oh the fan cfm is 1150

[bartZ32tt]

Oh the fan cfm is 1150

that's not nearly powerful enough, stock is 4000+ iirc.

[fairladyzz]

Can it be anything else besides the fan though

[bartZ32tt]

As someone else stated, you need to be sure to burp the coolant. There aren't too many things that can cause overheating. Is the koyo radiator brand new? If not, clean the fins out with an air compressor and brush. Same with the oil cooler and ac condensor since air has to pass through those before the radiator. If you confirm that your fan kicks on, you burped the coolant, don't have any coolant leaks, don't have a headgasket leak, and new thermostat engages (installed correctly), all that I can think of is an inefficient fan or a bad radiator cap. Do you at least have a fan shroud installed? That also makes a notable difference.

[Z32TT]

1150 is garbage to let you know, possibly the problem is fixed and that electric fan is barely keeping up at all which could be why the temp is slightly better but still not good bc you got a garbage electric fan.

[Oh Em Zee]

the fan isnt needed that much at freeway speeds..
if your problem occurs +65 mph, it is most likely not your fan.
City driving, then yes, it could be your fan.
you've replaced nearly everything but the water pump.
the comments about oil in the radiator fluid are not really that relevant to your overheating problem, but you should of course check.
we do need to know what symptoms of overheating you are having though, what speeds and what visually happens.
another thing worth mentioning because you asked if there could be other reasons for an overheat:
coolant system pressure, (making sure your radiator cap is sealing correctly)
this shouldnt apply to you because you got a new radiator.
lower radiator hose kinking (but you replaced your hose)
incorrect thermostat temperature (but you are having problems before and after replace)
making sure there isnt some ridiculous obstruction in front of the radiator
(seems stupid, but i've found an entire cardboard box stuck in front of my radiator when the previous owner hit it.)
if i think of anything else to look for i'll let you know. there really isnt that much left.

[Z32TT]

Engine speed doesn't matter..we have the ac condensor blocking the whole front of the radiator, If he's going 65plus its still going to over heat regardless and that fan doesn't help at all, 3500cfm should be the lowest you go electric either way but still electric fan tends to always be the culprit. It doesn't hurt to put your stock clutch fan back on to check one of the problems off your list

[fairladyzz]

The overheating occurs over long time city driving, it raises 1/4 mostly, but at idle when I start driving it goes down a little.

The reason I changed to electric is that the regular fan Clutch was bad

but it would be great help if someone know where I can buy a bigger electric fan besides z1, I couldn't find any on eBAy, the radiator is 20" diagonally so maybe a 18 or 19" fan will be good.

[DanDrath]

i have the ashspec fan came with the shroud its 3500 cfm after that my car never overheated again. My problems were bad thermostat and bad e fan changed them and now im fine. I also have a fmic blocking flow and i still dont over heat. My guess is its that garbage e fan as well. make sure to get a good one with a shroud around it. Also make sure that the fan is turning on at the proper times mine wasnt working properly so i just wired it to turn on once the car starts.

[jedijeff123]

mine had an overheating issue where it would be fine until about 10 mins of driving. then it would start steaming and hissing from under the hood and i could smell coolant burning from somewhere, it looked like a plenum coolant line. but it wouldn't leak until i had driven it, even after letting it idle for a good 20 mins it was fine. i just finished up replacing the water pump....i narrowed it down to that because the radiator was hot, so the thermostat was working and allowing water into the rad. the radiator wasn't leaking any coolant, so it was fine, and the hoses were fine, as the leak wasn't there at idle, only after driving. i guess i can't truly 100 percent say that was my issue because i have yet to put it all back together, but the symptoms of yours point to the same as mine...the only other thing it could possibly be is a blown headgasket. and i don't want to rebuilt my non turbo motor...

[evildky]

cheap electric fans suck, if your mechanical fan wasn't cooling you probably had a bad fan clutch of damaged fan, I highly recomend going back to a stock sutup, if you must run electric have a shroud made and run a fan that moves at least 2000 cfm

[fairladyzz]

You guys have been great help, where cani buy an elctric fan like the ashspec one you have, so far iv found a spal 16" 3300cfm for like 176, anyone know any sites?

[robomatic12]

To be honest I'd just buy a stock clutch fan and run that, they don't really fail that often. Electric fans have plenty of points to fail at

[raremotive]

+1 on shrouds, pre and post rad shrouds air flow needs to be more so controlled.

[DanDrath]

http://www.ashspecz.com/ashspec/Double- ... diator.htm thats what i have.

[tg]

water pump, when was the last time it was changed? (last timing belt change?).

It is very possible for it's blades to completely rust off if somebody used water in the coolant system at any point.

[CAzxKJ]

Hey I'm new to the z32 to family and ran into some issues with it.....I have a 90 z32 Manuel transmission. The problems I've ran into is a rough idle randomly happening when I'm at a stop which cause the car to some times shake and cut out, also causing the Cluster/head lights to dim in and out. Also my speedometer does not work at all just the RPM's. Last is the over heating that only happens when I'm stopped for a long period of time can someone please help???