Strange engine noise

byroninatlanta · Post by **byroninatlanta** » Sun Mar 09, 2014 4:41 pm

Here is a video of the strange noise my engine started making today. It goes away with higher RPM's. It sounds like the wind blowing across a bottle or jug. It is worse at low RPS's. My first thought was a vacuum hose had come loose but could not find one. Then I thought maybe leaking around the carb at the air cleaner. Then I thought it was the bearing in the fan. Then it sounded like the alternator. Now I am just confused. Any thoughts would be appreciated as I sound like someone blowing one of those plastic trumpets at every stop!

Post by **davemotohead** » Sun Mar 09, 2014 5:40 pm

Sounds like a Blower or Idler pulley bearing.

flat6_musik · Post by **flat6_musik** » Sun Mar 09, 2014 6:36 pm

Agreed.

Post by **bbodie52** » Sun Mar 09, 2014 10:03 pm

Of course pulling the belt and briefly running the engine should confirm that a rotating source — probably the fan blower bearing — and the noise disappears with the belt off. The engine top cover tends to act like a megaphone because of the roughly cone-shaped aluminum housing with a noisy bearing assembly mounted

in the center. That housing acts like an amplifier — making the howling sound worse.

A stethoscope can help localize the sound source. A piece of tubing can possibly serve as a fabricated substitute to help you to determine if the howling sound is emanating from the blower bearing or the idler bearing, or the generator/alternator.