Does head gasket replacement solve the Subaru 2.5L issues?


#1

Among the cars that I am considering for purchase are 1998-2001 Subarus with the 2.5L engine. I am aware that this engine is well known for head gasket issues, but if there is documentation that the head gasket has been replaced, does that eliminate the issues, or is there a design flaw in the engine itself (like the Northstars and their fine threaded head bolts)?


#2

Like the Northstars…The reason the head gaskets blow is a design problem…But once a skilled mechanic replaces them, they seem to hold up okay…


#3

Thank you. The reason I’m asking is because with the Northstars, if you were to just replace the head gasket, you’d quickly be in the same situation unless you drill and tap the block and install studs or thread inserts for the head bolts.

I assume then that the design flaw is in the Subaru head gaskets themselves and not in the engine block?


#4

I’ve done lots of Subaru head gaskets but never seen one that needed them twice save for driver error, like developing a radiator leak and driving an overheated engine until it quits.


#5

You will get different opinions as to why they fail…But improved head gaskets and careful torquing of the bolts / studs seems to cure it…The engines are very sensitive to overheating…Even a minor overheating incident can stretch the studs and release the torque on the nuts leading to certain failure…Also, re-torquing the head fasteners once or twice during the cars lifespan is cheap insurance but few people take the time and trouble to do this…


#6

Thank you for the info.

@asemaster‌

How difficult is a head gasket job on that car for someone who is mechanically inclined (but not a professional mechanic)?


#7

If recent, then I’d trust it for the number of miles it went the first time. Something else will likely fail first.


#8

I guess it depends on your tooling and ability. I’ve never done one with the engine in the car. I’ve seen it done that way, but considering that in a shop setting with hoist, air tools, etc. a guy can have the engine out and on a stand in less than 2 hours I think that’s the way to do it.

For the DIY crowd, plan a weekend and you should have plenty of time.


#9

Thanks!