hi, from reading about symptoms here in the forums, i think the smog pump on my 1995 E420 (116,000 miles) is in the beginning stages of failure. Every morning when I start the car, I got a slight squeaking/chirping sound that goes away after a minute or two. Last weekend, I got the squeak, and also a new noise that sounds like intermittent bearing/light grinding noises. These noises also went away after warm-up.

People here advise to just run it until it fails. My mechanic told me the same thing. What I'm wondering is: will I be stranded when the pump does fail one of these days? Also, will anything else be damaged as a result? The serpentine belt was recently replaced as part of routine maintenance.

If we determine that the noises are indeed coming from the smog/air pump, should we replace it as a preventive measure?

Thanks,

Warren

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2011 C300

Gone but not forgotten:

1995 E420
1990 500SL