Hello,
I am a new member who joined after I purchased a 1987 300SDL with some issues. This board has been immensely helpful in sorting out some of the issues such as a hard shifting transmission and AC blowing out the defrost.
Turns out, there was zero vacuum which was a gummed up nipple at the vacuum pump. Now there is vacuum and "lucky me" it shifts great and all my climate controls work properly.
Now for the real problem, tap tap bang bang that sounds to me like the #2 and possibly #3 injectors. It is driving me insane especially since it sounds so bad and yet the car runs awesome. I think I hear two different noises. One is a more of a bang possibly hard nailing and the other is more of a light tap.
I tried to include a YouTube video, hopefully you can see and hear it. This was my first try with an Ipad and YouTube.
Mercedes 300sdl- Noise in OM603 - YouTube
Here's what I know or don't.
142,000 miles
PO didn't have good records
#14 Head
The crappy orginal Vacuum Pump
Timing chain pretty sure is original
Injector nozzles are Bosios but don't know if they were properly popped and balanced
Starts right up but loud tap tap at startup with stumbling and a good amount of blue smoke
After a little warmup, stumbling goes away smoke diminishes taps continue
RPMs over 1200, banging noise quiets but taps continue
The most bazaar thing is going downhill, with a little engine drag and before it up shifts, it's as quiet as a mouse fart.
Any help trying to diagnose this would be very appreciated.