Q: crankcase gasket leak and viscosity of oil used in Impreza i might buy

car was in pennsylvania - and i crawled under the rear also- no sign of trailering.

interestingly, dealer said they'd replace the seal.

question is whether to pass on the car or not

Dealer says they looked and it was the crank seal, so they are replacing it (pre-sale!)

anyway, again, is a crank seal failure normal at 5 years or 32,000 miles? or, just a function of the gaskets they used then?

or, as i wondered, because of the 3 years of 15w-40 oil in Pennsylvania???

I think yor reasoning may be incorrect.

Likely, there is nothing wrong _because of_ the 15w-40 oil.

Although it is a tiny bit heavier than the 10w-30, this engine can handle it very well, even in Pensylvania. The Subaru boxer type engine, is not known to be an ultra tight engine like some of the Toyota's, Acura's, and others. Pensylvania is not a very cold location either. So using this oil grade 'in of itself' did not compromise the engine, or seals, I believe.

The point of contention for me is why would someone use 15-40? Was there a problem that 15-40 oil was supposed to help fix? Was it the seal seepage that someone hoped to stop or slow down by using thicker oil? If that was the case I would buy the car and have new seals put on.

But perhaps there was some engine knock, or valve noise, or other mechanical problem that a different viscosity oil was to improve.

My first bet would be that thicker oil was used to ameliorate the seal seepage, and the car is probably in good shape. But why would an owner of a new car decide not to have the seeping seals replaced under warranty???

Maybe it was a different problem, indeed?

Tough choice.

If you could only talk to the previous owner.

MN

well actually- to be sure- read the original post again.

one, i checked the records and 15w40 was used from the get-go for 3 years. then, i called THAT subaru dealer and the service dept told me they used that in everything back then.

so, i doubt it had leak or knock back then that the cust would have complained about. i see no complaints on the service shhets, other than a glovebox door or brake squeak that was fixed.

so, im back to wondering why seals would leak at 5years/32,000 mi.

the dealer IS replacing the crank seal. i just want to have an idea of that means anything in itself, or are there other factors.

so, the 15w40 wasnt switched to BECAUSE of a leak.

MN wrote:

I suppose if the PCV valve/system weren't functioning properly it could stress a seal. Or just bad luck getting a car with poor assembly/bad part during engine build.

Carl

Bad seal material and PVC type problem, or sloppy assembly were suggested.

Maybe driven very hard? Abused?

This could ruin seals I guess, that is high rpm's, redlining the engine, I don't know, maybe inspect the tires carefully for any signs of premature/excessive wear. If new I'd be suspicious but than 32k and 5years, sounds like somewhere near time for new tires anyway. Maybe inspecting the wear on brake pads is the way to go?

MN