K16 1.4litre: Crankshaft oil seal keeps popping out

In message , Adam writes

Sounds strange, are you using genuine bits? Is it tight to fit? It should need to be tapped into place. If it is a tight fit when you fit it then I would suspect excessive crankcase oil pressure. Make sure none of the rubber breather hoses from your cam-cover are kinked or blocked. If they seem OK then I recommend you remove the cam-cover and check that the steel gauze (flame trap) inside isn't blocked with carbon & old oil. If the crankcase breather system is OK then you may have a worn bore or rings allowing excessive combustion pressure to pressurise the crankcase. How old is it? How many miles?

Al

I agree with Al's suspicion of a breathing problem. Sounds like there's a air/oil pressure build-up which is bursting your seal. It nothing too sinister.

personally i've never come across one that just pops out on its own accord, and not really had any problems with excessive crankcase pressure either and i've seen plenty of k-series engines so for my money i would ensure the seal is pushed fully home, and square, and of course is a genuine part. once its all back together with a good seal in place you could check the pressure build up by removing the oil filler cap and manually testing while the engine is running. of course it may well be excessive pressure but i would expect excessive oil consumption and blue smoke at the exhaust all caused by worn rings if this was the case.