I bought a 1985 300d turbo with about 222,000 miles! The car is really clean. The original owner started getting service maintenance at the MB dealership early on, but at some point started to go to an independent shop from the oil change stickers I have found on the B-post. Various oil weights like 10w30 and 10w40 were used instead of the diesel rated 15w-40. I did find some issues with the car.
1) No air coming from the upper central vents.
2) A burning smell from the front of the engine area when running
3) Hard shift from the transmission from 1st-2nd
4) Various vacuum hoses that are cracked and some that have broken off
5) Hand primer is leaking, a new one has been ordered
6) An oil leak that is directly center of engine dripping on the driveway?
7) Weird chiming sound that when door is open, but when closed will turn off, but while driving and coming to a stop, the chiming starts again???

Any help with these issues?
Thanks

Hi! I just got an '85 300D also. Mine will likely roll 300,000 miles tomorrow depending on where I need to go for work. Unfortunately I don't have any explanation of your problems, but wanted to say hello.

Unlike yours, mine has no door buzzer sound. I also noticed the buzzer that signals the lights are left on is inop as well.

Do you think your oil leak could be coming from the front of the engine? I have a small leak there, wondering if maybe it's a common issue.

1) No air coming from the upper central vents.
Only fresh cool air or A\C comes through the center vents. The vacuum pod that opens them is a common failure item

2) A burning smell from the front of the engine area when running
Probably an oil leak, the oil leaks onto the hot engine and smokes\causes a smell. Start with the biggest\easiest ones and keep going. There's likely to be a few

3) Hard shift from the transmission from 1st-2nd
Pretty sure the harsh 1-2 shift is part of normal operation for 300D transmissions

4) Various vacuum hoses that are cracked and some that have broken off
Simple enough, buy some vacuum line by the foot at the autoparts store and have at it.

5) Hand primer is leaking, a new one has been ordered
Excellent, these can cause lots of issues when they start leaking

6) An oil leak that is directly center of engine dripping on the driveway?
Hmmm, If its dead center and dripping my first thought is the front crank seal. If possible give the engine a scrub with some degreaser and then look for where the leaks emanate from. While your under there inspect your oil cooler lines for leaks, and make sure your engine mounts aren't collapsing and allowing the power steering belt to begin eating through the oil cooler line.

7) Weird chiming sound that when door is open, but when closed will turn off, but while driving and coming to a stop, the chiming starts again???
This is very odd as these cars have an awful buzzer as the stock warning device. Could you maybe take a sound clip of a video of the sound?

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold