The air/smog pump in my 91 300SE makes noise when it's engaged. A rattle similar to that of an old AC compressor, not bone tingling timing chain or valvetrain clatter. Does this mean it's on its way out, already failed, just old? Is it likely to sieze and throw the belt or just get noisier?

Thanks,
Sixto
91 300SE
81 300SD

It could destruct and cause belt and tensioner problems. I have seen many unplugged.....

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

The air pump on my 103 engine 300CE is noisy too. What does this pump do and what are the effects of electrically disconnecting it ?

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1993 190E 2.0L (Euro.) sold
1991. 500 SEL (Euro.)
1991. 300 CE (Euro.) sold
1993. 500 E (U.S. spec.)

sorry all, I forgot the basics of this site, use the search ! Sixto, if you punch in airpump in the search section, there are several interesting write ups that certainly helped me. It seem that this is a rather expensive piece of kit and I plan on trying to replace the 2 bearings befroe I buy a new pump. Good Luck !

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1993 190E 2.0L (Euro.) sold
1991. 500 SEL (Euro.)
1991. 300 CE (Euro.) sold
1993. 500 E (U.S. spec.)