I have an '87 420SEL which had a barely noticable noise while driving last week which has turned into a very noticable noise now. It started out at certain speeds on certain types of pavement. Now it will do it loudly at most any speed on all pavement. It sounds like someone blowing into a bottle neck- kind of reverberating through the car. I thought at first that it was a speaker problem, maybe some feedback from the amplifier. Then I thought it was a tire problem, but I have looked at all the tires for signs of uneven wear, blisters, etc. and can't find any. The only thing that will make the noise stop (momentarily) is to tap the brakes. Have I got a caliper or rotor problem?

John, I'll give this a try,... do you possibly have a wheel bearing going south? Does the noise change with road speed or engine speed? Does the noise change if you are turning right or left, or following a tight curve (eg.... an access ramp)?

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Mithra

93 sl600
93 600sel

A mercedes is an inanimate object and therefore must respond to logic and reason.

It does not change with engine speed, as I have actually put the car in neutral and shut the engine off. It may be a little quieter at lower speeds, but not much. Turning seems to make no difference. I thought of bearings too, I know this certainly doesn't rule them out, but I have checked each wheel (on the ground) for any play in them and found none.

What about checking the driveshaft support bearing? It would still rotate if you are rolling along with the engine shut off.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

Where is the support bearing located? Trans or rear? That might just be it....

Right in between the two.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)