[Dank Dogg]

94 caprice 4.3
faint humming sound coming from under the hood
happens when idling or driving.

alternator was replaced about 3 or 4 weeks ago.

any ideas?

 

[Gene Beaird]

Does it happen all the time, or periodically, especially just after starting the car? If all the time, you might want to start replacing vacuum lines and the PCV valve if it hasn't been done in a while. If mostly after starting the engine, could be the AIR pump starting to make noise.

 

[Rocko350]

I've had an opti vacuum harness be noisey before. Same conditions.

Chris

 

[Interceptor9C1]

the electric air pump operating

 

[Rocko350]

midget under the hood with a kazoo....

Your turn


Chris

 

[Dank Dogg]

i checked again and no midget.

actually the alternator was making the noise...
replaced with higher quality alternator now issue is resolved.