240D won't shut down
 

My girlfriends daughter has a 1979 240D that won't shut down after you turn the key off. It will continue to run for 10-15 minutes, then you have to run it around the block, after which, it will then shut down.

Any ideas?

That's a vacuum problem which has been covered here numerous times. Search for "240D and vacuum".

It's rather likely that the car needs a new shut-off valve, located toward the back of the injection pump.

Ron
http://germanstar.net

it could be that that the vacuum hose to the shutoff valve at the rear of the IP has deteriorated or been dislodged. did the car have a recent oil change? that is a common reason the vac line comes loose.

This is a vacuum issue and was an easy fix on my 124. I imagine it would be even easier on the 123. Also, I would imagine that their is a manual shut off switch near the IP too (anyone?). This will save you some time and diesel.

My W123 240D has one.

M.

Yup, 100% sure that it's gonna be vacuum related. Check the "T" fitting on the big hose to the vacuum reserviour. Mine broke when pulling out the oil filter, and I never noticed. It can also be a cracked vacuum hose going to the drivers front door. That hose takes alot of bending, and it's a common failure point.

If you change that vacuum switch be careful and make sure the hooked part that goes inside the IP is HOOKED. A run away engine could spoil a nice day. One easy way to check this switch is to disconnect the vacuum line and then apply vacuum to it (suck on it) and if the engine quits then the vacuum switch is doing its job and you have a vacuum leak to find.

Thanks for all the replies.

Whether or not I get a chance to work on it is a subject for debate. My girlfriends daughter is 19, knows it all, and believes that a car should run forever without maintenance. When I encouraged her to go out to car last night and we could take a peek at it, she told me, "No, I don't have time for that." Funny, she had time to go out with her friends. Oh well.

Let'em kill a car and then walk (or bus) while they pay for the repairs or buy a new one. I've found that approach to considerably shorten the teen learning curve.

Scout — 1984 Female, 19,000 miles
Seth — 1981 Male, 22,000 miles [all "highway" miles (round trips to arctic circle, Maine and New Zealand!)]

Man... I should post a poll on how many folks on this forum have bought a MB that had been given to the daughter and was ran out of oil :( and toasted. I just bought a nice "80" 240D 4 spd that had been well maintained by import shops in Seattle then given to the daughter who ran it out of oil. There was a hole in the pan big enough to throw a cat through. my first clue was not being able to get the dipstick all the way down to check the oil. Only payed $150.00 (:D add on $100.00 + for ferry fares) an the interior is pristine which now resides in my Euro car. Not to talk stink about daughters but a Toyota or Sub might be a better choise.

And most teen-age sons too :-(