Head Gasket Failure?
 

Just bought a 2.5 STi PPP and fear I may have been catastrophically stupid. There seems to have been a coolant leak in the past as there is dried up coolant around the engine bay and also around the cylinder head gasket. There is also bubbling in the coolant reservoir.

However, there is no coolant in the oil, there is no oil in the coolant, there is no coolant leaking, there is no smoke from the exhaust, no smell from the AC and the car doesn't overheat at all.


Thoughts would be appreciated.

is the coolant bubbling in the expansion tank beside the battery? what about the heaters, do they blow on hot constantly on and off boost?

I had similar problems, just bought a sti ppp with bubbling noises and a coolant leak but it was only a radiator thankfully! They don't generally throw water into the oil though if the head gasket is gone, so for peace of mind get a sniff test done asap.

No, in the coolant reservoir near the bottom left of the intercooler. Doesn't appear to be any bubbling near the battery. The heaters are fine - always produce hot air whether on or off boost.

It also doesn't appear to be leaking any coolant as the level hasn't gone down at all. Only owned it a week though.

Where can I get a sniff test done? Any local garage?

you can buy one on ebay, cost me about £35 I think.

sounds like the header tank cap maybe leaking? that might explain the coolant over the engine. I thought mine may have had head gasket issues so did a lot of reading, I think the tell tale signs are mainly overheating, blowers not blowing hot air and bubbles in the expansion tank beside the battery after driving, or the expansion tank overflowing.

Local garage should be able to carry out a sniff test, probably cheaper than buying your own on ebay too. Doesn't sound like HG issues but I am no expert.

It just seems to have got everywhere which has worried me. Really hope it's OK!

I went through it all last week, I know how you feel! Try not to worry although it is easier said than done.

I got mine checked out by a specialist, full health check, and it was worth it to put my mind at rest. The head gasket was fine, but I was lucky as the rear hub locking nut had worked loose and was on the last thread!

Hopefully can book it in for a service asap. Glad they caught that.

Am in same boat with headgasket, but mines pushing coolant out of the overflow bottle but yet no smoke from exhaust,only does it on hard boost run had compression test done checked out fine

get sniffer test done to check

check your 1 or maybe 2 expansion and or radiator caps are ok , i was getting a smell of coolant but no other issues and the radiator pressurised cap was starting to fail , if it’s failing it looses pressure so no return of coolant to the system , just air filing up the system , i take it your coolant is not returning to the system and just staying in the non pressured expansion tank , the pressured expansion tank looks full till you start the engine then the level drops ? for me it turned into hg failure , i did a full rebuild including bottom end as bottom end failure is very common after hg failure as i found out twice ££

Wonder if op fixed this or still driving sweet 6 YEARS on :lol1:

I hope so , i need to check dates on posts , some reason came up as a fresh email as if it was a new post 😁🤣

Haha easy done mate,probably got that cr@p feature on that links similar posts.
I switched it off as it's a PITA

can it be turned off on an iphone please it’s all i use ?

Think so,I only use android but can't remember how I turned it off :wonder:

user cp / edit options / turn off related threads.

Love an accidental thread revival :thumb: would be interesting if the OP replies.

If your pushing coolant out of the overflow tank then it is likely the HG. This would could explain your dried coolant over the engine bay (I hope not).

Bubbling can be normal in the overflow tank see this link:
https://oppositelock.kinja.com/rando...ling-514111544

The vapour from the cooling affect can be seen as bubbles in overflow tank but they will stop once the turbo is cooled enough. This info is also described in the Official Subaru workshop Manual.

Bubbling in the heater matrix could just be a bit of trapped air and not HG. These things are very hard to refill without getting some air in it. Even after bleeding as per the manual you may not get all out.

If large enough the trapped air will just make it over heat and the fans will not stop it. I would check that first and the only real way of doing is to drain and refill from the filler tank rear hose very slowly. Usually the bottom rad hose does not get warm and heater does not blow hot air.

I sometimes hear bubbling in my 2.5 and it has done it for many years, talking to other WRX owners that have had their engine forged also sometimes get bubbling in heater matrix. If only minor then I would not worry about it unless your losing coolant or overheating.

A sniff test in not always conclusive either, I have seen many threads where sniff test was ok but after inspection the HG was leaking. Also do not rely on the car temp gauge as they are very slow use a OBD dongle so you get proper readings in real time. If you overheat it too much then you will blow HG or worse warp the block and heads. On my 2.5 fans come on at 97 degrees and cool to 87-86, fans turn off. This cycle is repeated, car never goes over 97. From cold on tickover this takes a good 20mins+ to get to 97.

Good Luck.

PS. Damn thread revival, I would love to know what it actually was.

@mistermexican not logged on for 3 years but now I'm curious to know.....dam you Mexican we need closure :lol1:

​​​​​​This is a blast from the past!
Unfortunately I sold the car a couple of years ago. But when I did she was still going strong. I went all over Europe in that thing too. As has been said it was the cooling for the turbo that's the cause - really glad I found those technical documents! It does make me wonder how many have been "fixed" when they didn't need to be.
Hopefully this provides closure haha!

Haha :lol:
nice one!