My 1992 300D has squeak too. Especially when it is humid, for example, on rainy day.

A dealer inspected this and suggested replacing airbag unit at $1400.
I did not do that.

I think there is a way to replace only contact area without replacing the whole airbag unit.

My squeak is intermittant now. If I repair the squeak now instead of waiting until it always squeaks, do I save money?





By the way, I have a feeling that the service advisor did not communicate well with the mechanic.

I asked him about airbag sticker on B pillar, which suggested airbag replacedment in 1991. I asked him whether the previous owner already replaced the airbag unit in 1991. When I went to dealer to picked up my car, the service advisor said, "we cannot remove the airbag sticker." Ooops, I did not request removal of the sticker! I asked my question again. Then he answered "there is no way to tell whether someone replaced the airbag previously. If you want, we can put new airbag. New airbag does not squeak."

I called FOR-MERC, and the tech's answer was different. The mechanic can tell when the airbag is replaced. He remove the steering wheel, see the airbag unit and find numbers written. He can figure out, when it was replaced.
Hmm, the dealer's mechanic removed the steering, but lost the opportunity to see the numbers due to poor communication skill of the service advisor.

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1992 300D 2.5 turbo diesel. 319 k miles.
124.128 chassis, 602.962 engine, 722.418 tranny.