Its a 1991 MB 350sd turbo diesel. Has around 160K miles. Ever since the car was bought, there has been a loud ticking noise, and the spring/tensioner spring always jumped.


Recently on a highway cruise, problems slowly progressed. First it started making louder than usual ticking noise. The brakes seemed like there wasnt much vacuum on them. It was also surging. This was a week ago.

Now sitting in the driveway, usually when you turn the key on, the glow plug light will shine a few moments later go off then you know its ready to start, well now the glow plug light wont shine and I believe they dont heat up either. Once you start its louder than expected. Loud ticking or clanking sound from the injection pump area. When idling, it surges. To kinda describe it, its like mmmmmmm *clack(motor jumps)* mmmmmmm *clack(motor jumps) etc etc... happens when you try to rev it also... To scared to let it run long enough to entirely warm up. The brakes were weird feeling also.

Any suggestions?

Loud knock? Hmmm, what's your oil consumption rate?

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

it sounds like your serpentine belt tensioner bearing is going bad. i just replaced the one on my 90 350sdl. i also had to replace the tensioner shock prematurely because it was going bad and i didnt realize it.

i dont see any reason for the brakes to be affected though.

nor the glow plugs.

good luck

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Already replaced the tensioner and shock spring thing pulley and all. Less than 2000 miles ago. Oil consumption is pretty high. The stop lever leaks, but much thanks to the write up, it will be fixed once its running correctly.

The brakes dont change when the car is on or off. Like there is no vacuum to the booster.

When you turn the ignition switch off, it still "diesels". It still runs.

The motor has one cylinder that seems to ping real hard every 4 rotations, im assuming.

Any help?

Thanks, Drew.

I don't know your vehicle really, but, the VP can do what you describe, and FWIU, it can take down a motor.
anybody wanna chime in with me?
John

The early style vac pumps (no rivets on the cover) like to fall apart and toss bearings into the motor. I caught mine just before it happened, it was knocking badly! My car sat for around three months until I scored an updated pump.

That 350SD has the lovely 3.5L that usually takes a poop, it's about at the mileage too when they fall apart.

Not sure when the updated vac pump came out, hopefully this isn't the issue with your motor. I've seen plenty of high mile 603s with the original vac pump... 300K or more.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]