2008-2010 2.5ltr Engine Failures
#2042
Scooby Regular
#2043
Scooby Senior
My 2008 STI hatch had hg failure at ~92,000 miles. I replaced the gaskets and fitted studs. That was about 3 months ago. I should have read this thread first. Now think my pistons need replacing.
It's difficult to say how things will fail but in my case it's very undramatic. Apart from high oil consumption, my car's running well, touch wood.
It's difficult to say how things will fail but in my case it's very undramatic. Apart from high oil consumption, my car's running well, touch wood.
What ppl seemed to forget to ask is... Why did I get HG failure?
With not asking they just go the route of having the HG replaced.
Then in a short space of time something else rears its ugly head.
Which was the problem in the first place.
#2044
Scooby Regular
my hg went on one car a year later the bottom end , so paid twice in effect , second car hg went bottom end sounded fine but i said do the whole thing , a crank bearing was on its way out so lucky i did , crank was saved , he said failure rates in a 2 litre after hg done about 25 per cent , failure rates on a 2.5 about 75 per cent fail within a year , the bores tend to become oval after around 80k miles so need a rebore but a minimal rebore , the valves normally need adjusting too , nothing to say it will go but in my books not worth taking the risk so just get it done in one hit , the first car went around 90k miles it’s now scrapped but hit 193k miles and engine is still running fine , don’t forget to get arp bolts done , if it has a sensible tune with not too much boost that helps too , real shame there are issues on the 2.5 as it’s a great engine , forging just gives that extra piece of mind , but it’s not cheap at around 5k£ to get it forged , i just look at it long term if i’m keeping a car for 193 k miles it’s worth doing , that’s three rebuilds i’ve paid for now , just wondering when my latest fsti 2.5 engine will go , it’s running like a train now , money now saved for a possible failure
#2045
Scooby Regular
#2046
Scooby Regular
My 2008 STI hatch had hg failure at ~92,000 miles. I replaced the gaskets and fitted studs. That was about 3 months ago. I should have read this thread first. Now think my pistons need replacing.
It's difficult to say how things will fail but in my case it's very undramatic. Apart from high oil consumption, my car's running well, touch wood.
It's difficult to say how things will fail but in my case it's very undramatic. Apart from high oil consumption, my car's running well, touch wood.
#2047
Scooby Regular
In reality when the pistons were carefully cleaned up there was one microscopic flaw on one crown edge which may well have been corrosion the biggest killer of engines due to short run condensate and standing. She is still running well 10k on from the head gaskets and head skim rebuild.
#2048
Scooby Regular
#2050
Scooby Regular
My bad description, the raise ridge round the upper face of the piston. But pot Mark's in the metal are clearly visible
#2051
Scooby Regular
No cracks in the heads either.
#2052
Scooby Regular
iTrader: (1)
my hg went on one car a year later the bottom end , so paid twice in effect , second car hg went bottom end sounded fine but i said do the whole thing , a crank bearing was on its way out so lucky i did , crank was saved , he said failure rates in a 2 litre after hg done about 25 per cent , failure rates on a 2.5 about 75 per cent fail within a year , the bores tend to become oval after around 80k miles so need a rebore but a minimal rebore , the valves normally need adjusting too , nothing to say it will go but in my books not worth taking the risk so just get it done in one hit , the first car went around 90k miles it’s now scrapped but hit 193k miles and engine is still running fine , don’t forget to get arp bolts done , if it has a sensible tune with not too much boost that helps too , real shame there are issues on the 2.5 as it’s a great engine , forging just gives that extra piece of mind , but it’s not cheap at around 5k£ to get it forged , i just look at it long term if i’m keeping a car for 193 k miles it’s worth doing , that’s three rebuilds i’ve paid for now , just wondering when my latest fsti 2.5 engine will go , it’s running like a train now , money now saved for a possible failure
#2055
Scooby Regular
#2056
Scooby Regular
iTrader: (2)
The bits you have highlighted are carbon,the pistons have far too much carbon to be any det going on, first sign of any high cylinder pressure / heat incidents would burn off all residue carbon, only leaving a fairly clean piston, the above all have high oil consumption symptoms.
The single indent you also highlight is piston position mark.
The single indent you also highlight is piston position mark.
Last edited by MOTORS S GT; 26 September 2019 at 01:45 PM.
#2057
Scooby Regular
The bits you have highlighted are carbon,the pistons have far too much carbon to be any det going on, first sign of any high cylinder pressure / heat incidents would burn off all residue carbon, only leaving a fairly clean piston, the above all have high oil consumption symptoms.
The single indent you also highlight is piston position mark.
The single indent you also highlight is piston position mark.
#2059
Scooby Regular
carbon bits arnt important so rather irrelevant. its those pesky nibbly bits
#2060
Scooby Regular
Time you invested in a decent screen. Those are all carbon/ash deposits and stand proud of the crown I wish now I had taken a picture of the clean pistons!
#2062
Scooby Regular
The states had all the class libel issues , where subaru was paying out a lot and where basically told to accept liability for the engine failure issues , shame the uk issues have not been accepted as subaru’s fault
#2063
Scooby Regular
My MY11 has just suffered headgasket failure at 64K, will have to see what else needs fixing when the engine is out and may as well get the clutch done at the same time.
Only spotted it because of a slight performance drop when overtaking on a dual carriageway, noticed the temp gauge up at hot. But really don't know how far I'd driven it in this state.
Looks like it might only a water gallery to cylinder leak, oil still looks good, am in touch with a couple of local Subaru specialist, who get good reviews on here, so will get it sorted and have some real gaskets fitted.
Doesn't matter how you treat them, and mines had a cushy life, but if you have naff parts installed from day 1 it's just down to luck, thank you Subaru.
Only spotted it because of a slight performance drop when overtaking on a dual carriageway, noticed the temp gauge up at hot. But really don't know how far I'd driven it in this state.
Looks like it might only a water gallery to cylinder leak, oil still looks good, am in touch with a couple of local Subaru specialist, who get good reviews on here, so will get it sorted and have some real gaskets fitted.
Doesn't matter how you treat them, and mines had a cushy life, but if you have naff parts installed from day 1 it's just down to luck, thank you Subaru.
#2064
Scooby Regular
get the bottom end done too , it’s a false economy to not get it done , it will sound and appear fine but only stripping it will reveal the wear and tear , forged pistons plus arp head bolts and cosi hg , the bottom end failure rate is around 75 per cent on a 2.5 v about 25 per cent in a 2 litre , ive been there before twice where bottom end appeared fine and it was not , first time it went within a year , second hg fail i said do the whole lot , one bearing crank shell was on the way out but crank was ok
#2065
Scooby Regular
iTrader: (4)
Only thing that could give that illusion is if the lighter part is actually lint from a rag or something and it gives the effect of it being holes.
Last edited by jameswrx; 21 January 2020 at 12:09 PM.
#2066
Scooby Regular
abre , what area do you live in , down south there is subaru4u , fb tuning , paul finch motorsport , just to name a few good ones , i’m sure they are many others out there , it’s worth using a trusted builder as there a rebuilders 😁and rebuilders 😕😢 out there
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#2067
Scooby Regular
I can see what he means, so wouldn’t say the new screen comment is totally fair. Even looks like there’s holes nibbled out and the shadow drops in to said holes.
Only thing that could give that illusion is if the lighter part is actually lint from a rag or something and it gives the effect of it being holes.
Only thing that could give that illusion is if the lighter part is actually lint from a rag or something and it gives the effect of it being holes.
#2068
Scooby Regular
iTrader: (4)
Take it from me those are white ash deposits that sit proud of the crown and have black carbon surrounding them. When the pistons were cleaned there weren't any flaws in the machined surface. The engine is still running on skimmed heads for those that are interested and still has only ever seen V-power in its 10years of life.
Thats great and all but I was just making a point it looks like damage & I could see where he was coming from. “Time you invested in a decent screen” just seemed a bit aggressive of a reply that’s all.
#2069
Scooby Regular
I live up in Saddleworth which is between Leeds & Manchester & there are a few recommended builders to choose from, like Richard Henry, HDC & CAMS all with a good Subaru reputation.
It will be getting either Cosworth or RCM head gaskets & will have studs fitted as well.
I've discussed the bottom end with all of them & depending on who I choose, the plan is to first see what the compression's like, then see what the bores & pistons look like before taking their advice on whether to split or not.
I have no plans to take the power over it's current 320, but I do want to have a good reliable engine as it's my daily drive. So if there's any doubt it will be having the bottom end done.
Also going to assume at 64K it'll be needing a new clutch, so could be quite expensive!
Andrew
#2070
Scooby Regular