Guys,


*EDIT* I have updated the description with more details.

On the '85 there is a rhythmic sort of chugging sound at around 1200-1800 rpm under load. almost sounds like an exhaust leak, but I don't think it is.

The noise has been there for the past 700 miles, and was there when purchased. decided to let it go at first and run a few tanks of new fuel (car had sat for two years) through before coming to any conclusions.

the noise:
- is not present at idle (normal diesel clatter)
- appears at 1200-1800 rpm, especially under load
- also appears at same RPM's while pressing down brake and accelerator simultaneously to load down without moving, or when just when revving in neutral
- seems about 1/5 of RPM speed
- is not loud enough to hear over the blower on high
- sound goes away above 2000rpm, runs great on highway

the noise is coming from under the mercedes symbol on the valve cover. what could it be?

what can i check when i take the valve cover off? what could be loose?

Thanks,
dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car