We have a 2000 SLK-230. Just recently the car has developed a very soft, high-pitched "whining" noise that occurs intermittently. It appears to be coming from the passenger side of the vehicle and will occur when the engine is running, regardless of whether the car is moving or not. Car has 53,000 miles on it and runs perfectly. This noise just started happening a few days ago and occurs every day (car is driven about 10 miles per day to commute to work).

Any suggestions?

Assuming it is not coming from a complaining passenger, is it from the dash area or under the hood?

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Prost!

In this case the complaining passenger is the very discriminating owner of said car! It is really difficult to pinpoint the source of the noise, but once you've heard it, it becomes quite noticable and therefore annoying.

My first suggestion for a remedy would be turn up the radio, but that will not cut it.....

Two items come to mind when a "high pitched whine " sound is a complaint , #1 alternator and on your model #2--- kompressor , get a piece of 4 ft heater hose or garden hose & listen down by each unit when the car is making the noise. ------ be careful near the belt with the hose .------ Ray

Or even the prop shaft if ur driving that is.

Pull the serpentine belt or drop the tension on it, start up a COLD engine, run it for 30 secs MAX, and see if the sound is still present.

If it is it is from the engine. If not, it is an accessory belt driven device.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Thanks for the suggestions. If it turns out to be an alternator or kompressor related noise, can these items be serviced without replacing them? As I mentioned, the car runs fine and all electrical items function properly.