If you have an older w126 class car, like a 1986-1991 420 or 560 SEL, I highly recommend you have a look inside your oil plan.

I opened mine up, and found the lower portion of the oil pump, which is made of rubber, broken into 2 pieces. The rubber was rock hard. I also found the remenants of a broken chain rail. If you have never replaced the lower portion of your oil pump, at least look at it, because it maybe well overdue for a replacement.

While the pan is off, you may as well replace the 'O' rings on the oil level indicator guage terminal, protruding through the block on the passenger side. The 2 'O' rings become hard and brittle and the inner one begins to pass oil. The rings are cheap, less than $1 each.

It was very easy to replace the lower portion of the oil pump. Just watch out for the 2 nuts, on the AC compressor bracket, which are connected to the pan screws. Remove the nuts first!

Joe

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1989 420 SEL