300E valve noise at start-up...
 

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

HOw is your oil consumption?
 

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

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.