Originally Posted by Gearboy
2008 Spec B
During a check for something completely different, my mechanic discovered that the head gaskets were beginning to leak. My completely stock engine has less than 16,000 miles of very moderate driving on it. I did a little research and found that itís not uncommon for the 2005 and later 2.5 engines to prematurely blow head gaskets. I've read that not driving the car often enough could have caused the problem because in boxer engines the oil and coolant don't drain away from the head gaskets when its sitting, but instead just sits there, soaking the gaskets, which can lead to failure. Read the article at the link below for more info on this.
Since the engine was apart anyway, I decided to rid it of the infamous ring land problem. So $4k later the engine now sports Cosworth pistons, rings and head gaskets. Iím aware of the piston slap problem with forged pistons, but Iím told that the 2.5 bottom ends often don't last much past 100,000 miles anyway, so to me it was worth not having to worry about ring lands. Quality oil like Motul should help extend the life of the cylinders.
Here's an interesting article about the head gasket issue:
the head gasket is stainless steel. and all cars always have coolant sitting against them.
i would say that this type of gasket is likely to sweat some coolant but not quite leak in a troubble some mannor.
as for the bottem ends giving out at 100 000 miles.. not much different than any other engine . what usualy happens is turbo faillure or some other stupid thing sends debris down into the oil pan witch is then later circulated past the oil filter bypass into the oil galleries right on to the bearings.
the ring land failures is related to detonation. the best piston in the world will also die eventually if there is excessive detonation.
piston slap will be noisy at -25 deg c ! sound like a diesel truck ! but thats just the way it is.