2006 Hawkeye STI coolant problem
 

Hi fellas,

I've had a bit of a look round using the search facility but nothing seems specific enough to answer my query.

I went on a "spirited" drive today for about 10 or so miles. When I stopped I allowed the car to idle for around 1 minute before turning off. I got out for a cig break and could hear it start to bubble under the bonnet. I took a look under and the coolant tank was bubbling quite heavily, to the point where it came past the rad cap and some went on the floor.

I started it back up and allowed it to tick over for another 10 or so minutes then did another 3-4 miles of spirited driving. I let the car tick over for another 5 mins before turning it off, and the bubbling came back (although not as vigorously).

I then drove the same route home but at a relaxed pace and had none of these issues. My coolant is topped up to full, my temperature gauge never budged and my heaters still work (there is no mayo on my oil cap either). It doesnt bubble when the engine is on, only once turned off.

I've owned my Subaru for just over a month now, and this is the first time this has happened. Its a standard car with 28k miles on the clock.

Any thoughts would be greatly appreciated.

Try a new rad cap ? If not it's a thermostat problem

Cheers, I've not had chance to check the rad cap, engine is still warm and don't want to take it off yet.

I was ****ting myself it was the head gasket, but I found it strange it wasn't overheating on the gauge (didnt budge).

If it were a head gasket there would be White in oil.

That depends on where the headgasket has failed, it could be the gasket has gone between the combustion chamber and the water gallery which will pressurise the water system and show symptoms like you are experiencing, headgasket issues don't always show up as oil in the water on a Subaru, it's best to get it diagnosed by a specialist before you start spending money.

Would that still happen with the engine off though? It wasn't bubbling like that until i turned it off and stopped again when i turned the engine back on

ive also got a 56 plate hawkeye sti and experiancing the same issues mate,only my temp gauge did move once,for about a mile (after some hard driving) but soon settled and its never done it since,but my expansion tank was full to brim and spilling out,when cooled down and took my resonater cap off that was very low,so was my rad,when i squeezed the top rad pipe it was doin nothing in the resonater tank,i just topped up and let it run for a bit,like you i was ****ting it that me HG had gone,but no other signs,just like you,and not losing any power,which id expect.so im assuming it was a block(for some wierd reason) yours could be same mate,hopefully anyway,and nothing major..keep us up to date:thumb:

Hi, yes if there is boost pressure getting into the water system when driven hard.

The coolant in the clear plastic tank near the battery should rise when hot then fall back down when cold, it actually gets drawn back into the rad as it cools down to top the rad back up due to pressure change/drop in the rad. If it does this and empties the tank then you must be loosing water somewhere. presuming there is no air lock, and the system is full when cold.

If it just keeps filling the plastic tank till it overflows it could be a rad or header tank cap that is not sealing properly but... then the car should overheat.... :wonder: If its only spitting water out after a fast drive it may well be the head gasket im sorry to say :( get a subaru specialist to have a look, good luck mate.

sounds like head gasket, i've know head gasket failure under load/boost..
a quick test is to extend the rubber hose from your reserve tank and place under nearside wiper blade , drive car for a while untill temp is a normal then give it some beans , if water/coolant spits out of pipe then will be head gaskets ....
ive had a couple of 2.5 do this , some with only 20k on clock

just noticed your location is manchester , i'm based in stockport, give me a bell and i'd be happy to take a look for you ..

taylor motors 0161 4741255 ask for rick

It does sound like a HG issue :( I would (my personal preference) take the car to Prosport in Stockport, 0161 432 9999, there isnt much that Pete doesnt know about Subaru's and they wont mess you about (not saying that anyone else does but hes straight to the point and wont rip you off like some main dealers).
He also has 20+ years of experience on scoobs and if you have an issue will give you some options.

Tony:)

Thanks for your opinions, and i think i've come to terms that my new car has hg issues :( how much is the going rate for an independent garage to replace them? Does the head need skimming? Is it worth doing any other mods whilst the engine is out? Is this problem likely to come back? Sam :)

Hi Sam, like Tony says you won't go wrong with prosport in Stockport I've never used them myself because I do all my own repairs, but I have heard nothing but good things about them.
Just make sure you take it to someone who knows Subaru engines inside out because a lot of so called mechanics will overcharge you and probably not do a very good job.