did the search...didn't find much...'90 300E, 147,500 mi., very well maintained since new...recently changed to Castrol 20W-50 (I know, not recommended oil) and have noticed valve noise (tapping) at start-up....it goes away w/in 3-5 seconds (after oil pressure comes up?)...I think I may know the answer before asking, but I've also read that a 3.0L may need valve work around 150K miles...opinions? experience? as always, thanks in advance for your help, Bill

Any other problems with the engine? You may only need seals, whihc is a lot less money than a valve job...

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J.H.
'86 300E

You live in a warm climate; Castrol 20W-50 is indeed recommended for a car of this vintage. You "might" get it to run a little quieter with 10W-40.

I'm sure there will be more opinions to follow. Some may suggest worn hydraulic lifters.