Hello,

I have a 1978 W116 300SD. I've had it now for a couple of months and have noticed that it has a "ticking" sound coming from the engine compartment.

I've cleaned the banjo bolt, adjusted the ALDA and made sure all links move to full stop and are unencumbered. I've changed the fuel filters as well as a Diesel Purge. The car sounds like a diesel should except for this &$^% ticking sound which is annoying me.

The car gets great mileage, does not burn oil, and moves far faster than I would have expected. I've taken a long screwdriver and "listened" to the injectors, IP, PS pump and anything else I can get to without getting caught up in the fan with "normal" sounds coming from them all. I tend to hear the sound more at idle than speed, but it does go up with the throttle and then "disappears" until I'm under 2K.

I did notice today after the purge it seemed to come and go, which is new for this issue. So long story short....anyone have any ideas? Is it a injector, or vacuum pump? I want to say it sounds like it's coming from "behind" the engine. If my ears don't deceive me, I'd say it's stronger on the drivers side of the engine compartment vs the passenger side.

Could this be a exhaust issue? Your help would be greatly appreciated...as it is driving me nuts.

Best Regards,
Duke1