W110 W111 W112 Sedan, BENZ AID - COMMON QUESTIONS AND ANSWERS

82 300SD Engine Knocking

This beautiful 1982 300 SD has been making a knocking/banging sound that I think is coming from under the valve cover. The noise is not audible at low RPM or before the engine warms up completely. At higer RPM 1700+ the noise becomes increasingly loud and is directly rythmic with the speed of the engine. After probing the noise with a stick I think it may be from what I think is the oil pump (under the oil filter, or the transmission. The trans was probed at the bell housing also close to the oil pump (I think.) Is there anything that could make a loud noise such as this in these areas?

Chassis Model Number

W126

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Diesel Engine Specific Aid

Water in fuel will not start

I have a '76 300d and i got fuel with water in it out of an old container that was supposed to be sealed. I made it about 200 yards before it died. I have changed both fuel filters taken all fuel lines off and blew them out and turned the engine over until clean fuel was squirting out of the injector pump and i even took the injector nozzles apart and cleaned them to make sure there was no water stopping them up. I have also put new glow plugs in it. It will still not start it will try to hit a time or two when u first try to start it and then no more it just turns over.

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Diesel Engine Specific Aid

4-matic question

recently purchased a 91 300te 4-matic, and need info on status of 4-matic operation. at start up, lights for 4-matic do not come on, nor do they when car is operating. other dash check lights do come on, though not all. the manual "4-matic funktion" switch in the engine compartment is on the "1" position, so i assume it is engaged. How do i know if it is working? how do i know if the dash light for the 4-matic function is burned out, or non-operational?

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Body and Interior Specific Aid

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Chassis Model Number

W124

A/C Comes on and off periodically

I have an 81 240D and when I turn on the A/C the compressor will kick in and it will blow really cold for a while only when the the analog dial is in the max-a/c position. However periodically it will kick on and off with no real reason behind it. I don't think it's the switch b/c moving it up and down does not fix the problem. It seems as though some part of the system decides its had enough and stops for a while. Anyone have a problem like this? Thanks.

Chassis Model Number

W123

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Body and Interior Specific Aid

Diesel ign. switch problems

I have never really understood, on our 123's, why I have to return the key all the way counter-clockwise if the engine fails to start. Strange voodoo with the vacuum shut-off? A peculiarly odd tuetonic accomodation for the hearing-impaired? What prevents it from functioning. Every now and then I have trouble with the switch stopping before the crank position, no matter what I do. Is this something that popping the cylinder and spraying WD40 would help? It is so intermittent that I could go for weeks without it happening again, or I could get stuck at the drive-up tomorrow. Thoughts?

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Diesel Engine Specific Aid

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Chassis Model Number

W123

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