Valve cover gaskets

[Tonyls430]

Does anyone else have trouble with their valve cover gaskets always leaking after a year of getting new ones ? Ls430

[Bykfixer]

Moved to a spot where LS430 owners would probably see this. 

As a rule valve cover gaskets tend to flatten so the need to squeeze them a little tighter by tightening bolts down is not unusual. Oil is under fairly strong pressure throughout the engine and in the case of a valve cover gasket it can find it's way out. Bolts can stretch over time too. Thereby reducing the tension applied to the items being clamped together. 

During assembly at the factory bolts are tightened to a given torgue spec but it's not unusual to have to re-tighten them later. If the gasket was replaced at any point it stands to reason after a "break in" period the bolts should be re-torqued. 

[JoeP7]

It’s wise to use OE valve cover gaskets. Rt side gasket leaks will torpedo your Alternator if you let a leak go too long.

[RX400h]

Ours were replaced at an independent repair shop after the gaskets started seeping after 14-15 years. That was a few years ago and they gaskets are still sealing very well.