Hello all,
New to this list but not to Benz, can someone help? I've got a '87 300TD with 215k miles and the engine has recently started to make a louder than normal rapping noise at idle upon cold start-up. If revved beyond 1800rpm, the noise goes away and it purrs smoothly. Also after driven for a while and warm, the noise is less noticeable at hot start-up.

Any ideas on wht may cause this?

I have used different fuels from different suppliers to eliminate fuel quality issues
I have also run two tank fulls with fuel conditioner/cleaner additive
There are no fuel leaks at the IP or anywhere and all seams buttoned up under the hood. No unusual oil consumption etc.

Have not checked timing chain tensioner or chain slack, but I would assume this type of problems would not go away under load-speed, or am I wrong here???

Help Please


1987 300TD 215K
1986 300SDL 363k