You Guys are great,

A rocker arm would definitely explain the noise that I´m having. I will open it up this weekend to have a looksee. I´m not sure though if I understand how a faulty hydraulic compensator would explain this noise. The noise is always there except when the car is really cold (like around 0 F or -15 C) at startup. After some 10 - 20 seconds and all through warm-up and at warm conditions and independet of Rpm i have the tapping noise.

But I`m curious How to diagnose a bad hydraulic compensator?

Do You also have any ideas on what could be causing the right cylinder bank to be running lean and the left to be rich?

Please give me more feedback, I really really appreciate it.

Once again You guys are great.

Mikael Westerberg
1984 500 SEL
Vanersborg, Sweden