How common are warped plastic valve covers?

Joined
May 3, 2022
Messages
89
I cleaned up all the mating surfaces until they were pristine, bought a new OEM cover gasket, torqued everything to spec, and I'm still getting leaking through some bolt holes.

I've read about valve cover warpage with some BMW owners, but now I'm wondering how common it really is across the board.
 
Joined
Aug 30, 2004
Messages
28,230
Location
CA
Very common in Euro land, especially BMW. Not sure about the rest of the industry.
 
Joined
Oct 31, 2017
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4,657
Location
California
I've never had one warp but crack. I like aluminum valve covers. Sometimes there are aftermarket options or on some engines an older version of the same engine had aluminum valve covers and they will fit the newer version of the engine.
 
Joined
Jul 16, 2022
Messages
109
did you use RTV? Put a good bead on, hand tighten and leave overnight, then torque down.
 
Joined
Nov 20, 2006
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28,960
Location
MA, Mittelfranken.de
Put some hylomar M (thin bead) on the cover especially around the bolt holes and on the side of the gasket that meets the head. No rush it doesnt dry and no need to leave it to cure because it doesnt do that either, drive it right away.
 
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