Matt Chute

Hey folks! Just purchased my first Mercedes (and actually first car really). It's a 1982 300d turbo diesel in very good cosmetic condition with about 250k miles on her. Took it to an independent Mercedes auto shop for a pre purchase inspection and the mechanic said it was a great deal and in good shape (zero rust, straight body, no dents or accidents), baring a few repairs and some necessary maintenance.




However the reason I'm posting is because I'm having trouble with the fumes of the car. When driving her around I notice after about 30 min of driving, my eyes, throat, and chest are irritated, also slight ache behind my eyes and a tight chest for a while after. It's not a coincidence because it's only after I drive and it started happening after I bought the car. Also living in LA and walking everywhere for the last 6 and a half years I've been used to smog so it's not that. I know diesel cars have a strong smell and she's old, but this seems out of the ordinary.

Some points of interest

1. I notice it the most when the windows/ sunroof are open and I'm at a stop light.
2. I still notice it when the windows are rolled up but it's greatly reduced.
3. I took it to a mechanic recently for new brakes, tires, an oil changed and another inspection and he said he didn't notice the fumes really, but he only drove it for a few mins.
4. It doesn't have a specific smell (such as a maple syrup sweet / coolant smell) more just like fumes of a diesel/ gas
5. If I lift up the hood and check it out, it's that same smell and even stronger.

The car hasn't had maintenance done in a while except for what I've done, but the mechanics say it needs the following:

• new motor mounts
• New transmission mounts
• General maintenance (valve adjustments, oil filter changes, etc.)
• New AC compressor

I known very little about cars but I love trouble shooting and repairing things (I work for Apple and repair/rebuild computers) and I'd love to learn. Been combing forums and such but thought here would be a great place to post.




I went under the hood and took some photos of questionable things. If you guys see anything looks wrong please let me know. Also if anyone has recommended trouble shooting steps to try and isolate that would be awesome.

https://m.imgur.com/gallery/c5X2V

Lastly, any advice for having a diesel car and a w123 in general, or resources you can point me to (checked out the ifixit page for w123s) that would be awesome!




Thanks again, I appreciate the help and time!

• Matt

rocky raccoon

Congratulations on your old Benz Diesel Matt. I have had three of that vintage and currently daily drive an '83.

Barring something obvious like a massive fuel or exhaust leak, the most common odor source in these cars is caused by a simple oil leak. The valve cover is held down by only four nuts and unless a good gasket is used and the nuts are carefully torqued to spec (10 ft/lb) the oil seeps from under the gasket down to the exhaust manifold where it vaporizes and smells terrible.

Look around the perimeter of that gasket for evidence of oil seepage. If you see it, first try to torque the cover down. Be careful to not overtorque, 10 ft/lb is not very much. If you do it can distort the cast aluminum cover then it will never seal. Worst case you may need a new gasket and you may as well learn to adjust your valves while you are in there.

There are many other sources of oil leaks on our cars but the VC gasket is the most common and the one that produces an odor.

Could not open your photos.

Matt Chute

Thank you so much for the reply!

I just picked her from taking her in for a valve adjustmemt, as well as to replace the valve cover gasket, motor mounts, and to the air filter, and both oil filters. Also had them run a can of diesel purge. Some new things were discovered (metal shavings in the fuel but that's a seperate post) and one of those was that the down pipe coming from the turbo Is leaking fumes They were not sure what the part called is as they don't specialize in Mercedes or diesels so I'm not sure one what to order. Ive attached a photo in hopes that someone might be able to tell me what part I need to order.




If you happen to know that would be awesome!
Also in terms of adjusting the torque of those bolts, I don't have a tool set to do that. I'm pretty new to all this so if you have a recommendation for a set that would be awesome. Thanks!

rocky raccoon

Can't offer a part number for the pipe but it should be easily identified on the illustrated parts diagram at a dealer.

A torque wrench is needed for the nuts. I recommend a 1/4" drive beam-type wrench since the values are quite low and may be out of range for a 3/8" drive. Your mech should understand.

Matt Chute

Word! Thanks Rocky!

Matt Chute

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