Join Date: Dec 2008
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Buzzing when cold, using fuel
I seem to have all of my local fellow 7.3 owners stumped on this one. Here's the problem- When the temperature outside drops to around 32 F, there is a loud buzzing sound under the hood that I cant seem to pin down.
It makes no difference whether it is plugged in or not, and the buzzing doesnt start until I am about a mile down the road. It only happens between 1000 and 2000 RPM approx. if I shift to 5th gear at 35-40 MPH I drop to 1000 RPM and the sound stops. It will also stop if the clutch is depressed or if accelerating, but sound will resume when speed steadies. Also, once the engine is good and warm, (depending on temperature), or if the engine is shut off for a few minutes after initial warm-up, the sound will disappear
The biggest worry is that while it is buzzing, you can watch the fuel guage drop very quickly. Within a few minutes, a quarter of a tank of fuel will be gone. At 4.60 a gallon, this is a little expensive!