Hello,
I've been trying to isolate a belt/pump/motor growl for a couple of weeks now on my 2.6 190e. Changed the mono belt today and retensioned, but now I notice that the growl in the belt/pump/motor group is almost constant now. It was somewhat intermittant which led me to think that it was belt/alternator related and would worsen when the alternator had a larger load.

Changing the belt removed the belt possiblity. The worst noise seems to be coming from the side opposite the alternator however and more specifically, like it could be the refrigeration compressor. The clutch assembly is not oily, but is a somewhat discolored brown, perhaps indicating heat. The clue that I do have is that I am not hearing any perceptable changes when I engage the heating system and the interior of the car is not defrosting as it normally does. Also, when the engine is running, the outer pulley of the clutch is spinning, but the internal portion that would drive the compressor is moving sporadically. Would the noise I'm hearing be from a failed compressor?

How can I isolate the compressor as the culprit and if it does turn out to be the problem, what's the best replacement option?

Thanks for any help!!

Denny Rofkar

I had the same problem, it turned out to be the belt tensioner pulley. This was on a 190E with 115K. When the belt was not on the pulley, it ran smooth, but with the belt on and the engine runnung, it growled quite a bit.

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