Many moons ago I aquired a 76 Benz 240D for a song, it had been sitting and with a little work it ran like a top. I drove the thing to Washington from Cali, 20mpg as compared to 9 in the Cheby 4x4 to visit sister, The more I drove it it seemed to Ping or knock under full throttle as a gasser would on cheap gas. It wasent much but it became worst as the miles racked up. What would cause this?? I talked with several Benz techs and never got the same answer.

Thanks.
Apache ???

 

Over advanced timing can make that sort of noise.

 

My 95 CTD did that and the local shop that fixed it told me that the overflow valve was bad. I assume it was going very lean, cause it only would do it on the highway at speed.

 

Sounds very much like a stretched timing chain. I know this might not apply but I was trailering a few MB's and had a couple of guys driving two more and the gasser 380 SL lost the chain. Actually I think there was more then one in those engines. I overheard one of the mechanics saying you notice this by the sound of the engine running advanced. I dunno if that applies to that diesel though. If it is applicable...might be a good idea to get it changed before it breaks as it can cause more damage if it breaks or jumps a few cogs. It might have done that already but theres so much slack and the teeth could be very close together that it has not got to the point of bending valves etc.

Let us know what you find out. I like them old diesel Benz's