WRX Overheating
 

Hey Folks,

Hopefully someone will be able to help me as I'm getting a little exasperated with my 2003 WRX sportwagon overheating when driven over 60 mph, up a steep hill or when driven hard, its seem that the engine is not able to cool itself down when its being pushed.

A few months ago the problem was much worse and the car was overheating at idle, so I had the coolant drained and the system bleed to eliminate any possible air bubbles, and I have also had the temperature gauge replaced.

This made a lot of difference but the problem still persists!

Any thoughts appreciated.

Ally

Have you tried refilling the coolant system via the turbo coolant pipe? Seems to be the best method for filling. I've done it on mine and never had any trouble.

head gasket sniff test done ?

Hi, thanks for the replies, I put the car into Subaru and they couldn't find anything conclusive for head gasket failure, so they drained the coolant and bled the system. They also carried out pressure testing and co2 leak test, everything seemed ok.

I would guess waterpump not working properly.

Are you losing coolant? Look for small air bubbles in expansion tank when engine running. If you see that then you've definitely got a head gasket problem.

Hi, the waterpump has been checked and its ok, I'm definitely loosing coolant, but no air bubbles in expansion tank.

Must be a leak then either internally (head gasket) or pipe/radiator. If the latter case, if the leak is small then it can very difficult to locate. Try this: top up coolant so that it's full, warm up engine fully then with plastic undertray removed, park car over large bit of card board (underneath engine and rad) to see if there's any coolant drips. Might help locate source.

Thanks mate, I'll try that, might explain why the garage have spent a two hours looking but cant diagnose the problem. They mentioned possible head gasket but the usual tests are not indicating that's the problem.

Have you got tiny black particles in the overflow plastic tank ?

Hi, no everything looks clear inside the overflow tank.....

checked the thermostat?

I'm not this has been checked, I had a mate look over it and he noticed that the fans didn't seem to working correctly..

Shouldnt be overheating at 60 mph due to air flow through the radiator, even if both fans not running.

You mentioned fans not working properly, can you give more details. Both fans should be running at high speed once the preset coolant temp is reached.

If coolant level is dropping then it must be going somewhere. If it was just overheating due to defective thermostat or fan then the coolant would be pushed into the overflow bottle so you would see that the plastic bottle is over the full line (maybe full to the top) at the end of a run. The coolant then should return to the radiator once engine cooled. I still think there's a leak.

Hi, again thanks for all the advice, the fans were checked when the overheating was at idle, and it was here the problem was diagnosed.

DJB3, there's definitely a leak as I have had to top up the coolant several times now,
I had the radiator replaced recently by a non specialist, do you think this could contribute to the fault say if the radiator was not fitted properly?

After coolant drained, eg due to radiator replacement, coolant should be poured in, very very slow to avoid air lock in the cooling system. Do a search on coolant change and all the advice is to pour in the coolant very very slow. I believe you will be able to pour in about 5-6 litres of coolant if you do it slowly.