Hello folks. I'm the proud new owner of a 1983 300D Turbo Diesel. Currently, the engine continues to run for approximately 10 seconds after I turn it off and remove the key. I am troubleshooting the problem and have found alot of helpful info. My question is, will my engine be damaged in the meantime until I fix the issue? Thanks in advance for any helpl.

 

Your car does this because it most likely has a vacuum leak. To test this, after you turn off the key and it fails to stop, hit the gas. If the increased engine speed (and thus vacuum) causes it to die, the problem is certainly a vacuum leak.

Your car will no more be damaged doing this than it would be while running.

Of course, if the "dieseling" is caused by excess carbon buildup then yes, you will eventually damage the engine.

 

Vaccum leak or module. Mine I pulled the line off [ car will not shut off now]the module and put one on so I could put a vaccum on it with mouth, and it shut off immeditly. So that showed a vaccum leak, Found the leak and is working great now. The module could also be sluggish and causing it too, check for leak first. I have cleaned some of my heater vaccum modules and got them working again/ atleast for now.
87 300D 215K

 

chec the vacuum pump.if it continues to run because of thie pump not working then sometimes the diaphram will rupture and oil will pump from engine into vacuum system and air cleaner.

 

I got my 81 300D 5 weeks ago and the engine does not shut down when I turn it off and pull out the key with the driver's door unlocked. If I lock the driver's door, it gradually shuts down in 4 sec. Another situation is, as long as I lock the driver's door before turning the engine off, shutdown is normal. The former owner said that its a vacuum leak. Didn't want to believe him till I got into this forum. Can't believe someone who didn't say much until you discover them.

Good to have a diesel Benz again. My 1st was a '75 200D in 1982, passed down from my Dad. I pray that this will not give me nightmares.