I bought an 87 560 SL recently and enjoy it very much. It rides nicely and has enough power to have fun.

Question?--Are the fuel pumps on this model supposed to be noisy? It isn't erratic but just surprised me that it is so noticable at idle. Generally, I turn on the radio an ignore it but my wife asks everytime I turn it on if it is as it should be. The engine and all other parts of the car run beautifully.

 

yes, it is audible.

if you hear the regular business hum noise which is low in pitch, then it is quite normal.

but if you hear it as an irregular pitch and louder than before, it is an early sign of breaking down.

the reason why they put two fuel pumps on it is to "reduce that noise", and not to give more fuel/pressure. some even got damper for the noise, but they really cannot omit it. see if both of the pumps are still working (if you got two).

lately, they simply use the rotary or screw type fuel pump which doesn't make any noise at all. it was far smaller, can deliver good quantity, and only one is needed.