hello

after searching the forums, seems there's a general consensus that if your fuel pump starts making a loud humming noise, that it's on its way to failure and should be replaced.

my 1987 560SL makes this humming noise specially on really warm days, and though I thought I'd tracked the noise to the left side of the gas tank I guess it could be coming from the fuel pump which is in the right rear near the wheel. Will check that area specifically next time I hear the humming.

my question is this though, if the humming is the pump going bad, why does it not stop when the engine is stopped? On my car, it keeps up the humming, sometimes quite loud, until I go to the gas cap and open it, releasing all the built up pressure. The noise then disappears immediately.

any thoughts or explanations as to the above behavior?

thanks in advance

__________________
D. Chang
Network Integration Engineer
MCSE, CLP, CCNA