When I go in reverse (i.e. backing out of the garage), I hear a sound like tat-tat-tat that in synchronous with the speed in which I am going in reverse. I always hear it when the engine is cold. It is not always audible when the car has been driven a while. Any speculations on what the issue could be? It is a '92 124 body.

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Mark Herzig
1992 500E (82,000 miles)
1987 300SDL (105,000)

Hello Mark,
Thanks for bringing this up. I have a 92 500SEL and I get the same wierd tat-tat-tat sound when I back up. I also would like to find out what causes it.

Fred Berry

Sounds like you are describing are the most difficult problem to find & dignose. Suggest you have your technician look at the car in his garage under the same circumstances as described. Try parking the car in the garage backwards & see if the same sound happens in drive. Being in an enclosed area will amplify any noise & might be a normal noise.

Funny that several people have posted this ... I have the same thing with my 90 300e - noise when backing in synchronous with speed.
And it's not "in" the garage only. Everything else seems normal, except the engine a bit loud on idle (~550rpm). I also think that my transmission a bit loud sometimes.

Could this noise be a 1st sign of something bad?

Do you notice the sound when the car is warmed up?