M4RKG

iTrader: (22)

My Impreza WRX (MY97) has started to over heat when at both idle and when driving (except for motorway driving which its fine)

If i just let it idle and have the heater blasting hot air into the car then it sometimes is ok.

Thing is, it did it before it went into Subaru for a FULL service, then was fine, and about 2-3weeks after the service its started doing it again??

Any ideas, i'm thinking i've either got a leak or the cylinder heads gone... could anyone shed any light on how i would go about identifying which??

Fan kicks in etc. when it starts to get hot, but doesnt help the matter

Cheers, Mark

dj219957

check the simple things first.........like has it got enough water in it!? are there any leaks you can see? any water coming out by the battery on boost?

M4RKG

iTrader: (22)

No leaks that I can see, where are common or weak points? There's a coolant tube next to battery which is empty, is that right?? Is it just an overflow? Where's best place to check water/coolant levels? Sorry I'm not the best when comes to Subaru's

bighead

iTrader: (1)

check water level in header tank on the inlets maniflow and you might have a leak on the radiator hose (top one are very common to leak )

M4RKG

iTrader: (22)

Cheers. And best way to check if the cylinder heads gone?

bighead

iTrader: (1)

you will know if the heads have gone as the coolant will bursting out of yr header tank cap and over flowing from the plastic filler bottle with the yellow cap by the battery ...this is from experience !!
if there is coolant spray around the radiator area and inside of bonnet , its will be a fine crack on the top rad hose .
if you are not losing coolant , it might be a faulty thermostate or the coolant system needs bleeing,

oh best way to check heads are a compression test /gas analyze....but that does no always show up as the heads have gone (again from experience ).....good luck m8 , hope its not the heads as it will be a nightmare .

my car has been off the road since last aug because of blown heads !!

M4RKG

iTrader: (22)

What does the F and L mean on the plastic filler bottle?

bighead

iTrader: (1)

lol... I'm guessing F is full and L is low :wink:

M4RKG

iTrader: (22)

Hahahaha, ah yea. So seeing as there's no coolant at all in that filler bottle probs means that I've got no coolant. Reckon that probably is the problem like as it fixed itself after service. Just guna be finding the leak that's the problem

M4RKG

iTrader: (22)

Right, filled the plastic filler bottle (next to battery) up this morning, just above the 'F' switched the engine on and it stayed put, didnt drop or anything. Went for a drive, came back and was gone, nothing at all in the filler bottle. Does this mean i've got a leak?? The coolant itself was only changed 2-3weeks ago at service.


Ta

M4RKG

iTrader: (22)

... continued.

Just had the car out again, not losing coolant (noticeable anyways) under the bonnet when on boost. Nowt dodgy in the oil. Really dont think its the cylinder head thats gone.

Anyone??

dj219957

if the bottle you have filled is now empty then its either been sucked into the header tank (which its supposed to do) or been kicked out under boost.
the whole purpose of the bottle by the battery is to allow water to move in and out of the header tank depending if the car is hot or cold. the level will be high when hot and low when cold.
you need to remove the cap on the header tank on the left (when car is cold) brim it with water. then fill the coolant expansion bottle by the battery to between the l and f line.

check the level in the header tank on the left

M4RKG

iTrader: (22)

Will do mate cheers

martiboy

When my heads went I noticed there was alot of pressure in the cooling system.This was shown by the top hose to the rad being under alot of pressure.With the engine running and filled with water and the rad cap on you should be able to squeeze the top hose fairly easily.If you cant it could be compressed gasses entering the cooling system via a crack in the head/heads.Just for info I showed the same symptoms as you but it gradually got worse over a period of a few weeks.Eventually I blew a hole in the rad.I replaced it with a new one and the same happened again !
Good luck !

martiboy

When I said "engine filled with water" I do mean just the cooling system !!

dj219957

pressure in the system is normal, i get a firm top and bottom hose after a good run.
over pressurization, bulding of the hoses is something else.

M4RKG

iTrader: (22)

Just a quick update on this one, cars into subaru on monday to have the radiator replaced as there was a hole in the back of the current one... after reading some of the replies again on this thread, does this mean that pressure is building up too much in system. Subaru mechanics all said its defo not the cylinder heads as they wouldve picked it up when they did the £575 service 3 weeks ago and very much doubt its too much pressure and it only leaks out of the hole sometimes, and is most likely due to the fact its the original radiator so being 12 years old.

Opinions??

Ta

TonyBurns

iTrader: (3)

The cooling system needs to be pressurised to stop the water boiling, if when the car is running (for a few mins) and the hoses are soft, then you have air in the system, they should be pretty hard tbh.

Tony

M4RKG

iTrader: (22)

Ok cheers, pretty sure they were okay as thats one of the things I did check as did subaru on friday, but obviously a couple of the above posts were conflicting. Is the normal running temp. approx 88oC??

joz8968

iTrader: (13)

I happen to have a 71deg C opening sports stat and my urban driving (i.e. keeping below 40mph or so) ave. temp. is 83deg.

The OEM stat opens 7deg later at 78deg... so, yes, I'd say your 88deg operating temp. seems in about the right area.