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2002 E320
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107 Posts
Discussion Starter #1
Hi;

My 1994 E320 recently started making a growling noise from under the hood. A stethescope tracked it down to the rear of the smog pump which was then rebuilt (at a cost of $520). No change. Someone suggested it was the innards of the catalytic converter but it really sounds closer to the block or the accessories. It sounds like either a bad bearing, a loose heat shield or a out of balance fan if you can imagine all of those sounds together. It is definitely engine rpm related and increases slightly in pitch and volume as the rpm increases.

All other parameters are normal.
Suggestions?
 

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E320 wagon
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953 Posts
The air pump ( smog pump ) has a timed run cycle . One minute or less on start up , with a clutch similar to an A/C compressor .
 

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2002 E320
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107 Posts
Discussion Starter #3
Thanks Uboater. That was one of the clues that we missed. The noise is constant whether the clutch is engaged or not. Of course, we picked this clue up after spending $$ to rebuild the pump! D'OH!

I just picked up another 1994 E320 for parts so maybe the next attempt won't be so expensive!

Scott
 
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