Have a '90 300E Base SOHC 6 3.0 engine. Engine has 200k on it and head was redone by a good shop at 150k. Engine has always tapped for 5 or 10 seconds when you start it cold, then quiets and that's it. Oil is changed religiously every 5k with Syntec 5W-40. It runs like a charm. Daily driver.

Two days ago it started tapping on and off when driving it. Taps the same whether driving or idling. Pressure gauge shows plenty of oil pressure. Oil level is full and oil condition is clean and fresh looking. Noise comes and goes. Sometimes it is persistent, sometimes lasts only a few secs. TONE of noise changes as well, sometimes is a solid sounding "clack" sometimes has more of a ringy tone to it. Always emanates from under the valve cover. Even though the pressure appears to be fine, a peek inside the filler cal lead me to believe that the valve train, while not dry, appears that it may be drier than it should be. Again, pressure indicator is showing 3 bars running and 2 at idle.

I am thinking that I have a lifter(or maybe 2 ?) collapsing But this is actually quite a sudden development. I am also wondering if I have a sudden oiling problem to the top of the engine.

Anyone ever experience this before with a 3.0 SOHC ? Any one have any input or ideas? All input is welcomed.

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Andy_M
'98 W140 S320 Black/Black
'06 W164 ML500 AMG White/Grey
'03 Porsche 986 Midnight Blue/Grey