The rear main seal is trashed on the CRX, could positive crankcase pressure have caused it? My garage is a ------- mess now.

 

DING DING DING we have a winner.

 

positive crankcase pressure can do it, and some other ideas are old seals, high revs like into the 8000s, and a damage crankshaft damper.
it would cause extra vibes that will ware out parts.

 

I'll go with positive crankcase pressure and old seals.

The car is just freshly boosted (about 5 months) after sitting for almost 3 years.

 

Definately dried out after 3 years of sitting. If i remember right, those are usually viton seals, which dry out very quickly and will rot if not kept properly lubed. Have fun changing that one buddy

 

Not my car, I didn't let it sit for 3 years. If I would have started the project it would have sat for 2 weeks.

 

Might not be rear main - look very closely. I had crankcase pressure blow out the oil pan seal just below the rear main - I ended up dropping the transmission for absolutely no reason whatsoever.

Tip: Using rubber hose, even the oil-resistant OEM breather hose or fuel line, is highly prone to blockage. Just run the little $15 riceboy PCV filter sold at Autozone in the riceboy isle and be happy. All my excess crankcase pressures have been caused by the stupid little valvecover vent + me not wanting to 1) install a proper catchcan or 2) put a goofy riceboy PCV filter on the engine.

 

Rear main is replaced. I might do the oil pan gasket tomorrow just for good measure before I put oil in it. I've already got a breather on the valve cover, but now I'm going for the catch can soon.