97 Taurus ~120,000 miles, 3.0 vulcan engine.

At idle in gear, the car makes a "buzzing" noise from the front of the car,
sounds like a heat shield slapping around, but I can't see anything
obviously loose. If you take it out of gear or touch the gas pedal, it goes
away. Also, if I put the AC on, the noise changes to a random metallic
clang/tap along with the buzzing, like hitting a wrench against a piece of
metal. Again, only at idle in gear, and it goes away as soon as I hit the
gas a touch. The AC functions fine, IE blows very cold air.


I haven't ruled out the heat shield issue, but the totally different (and
much louder) noise when the AC compressor engages makes me wonder.

Any guesses?

Turns out the noise is the serpentine belt slapping around at idle, it's not
under enough tension. Would this be due to belt stretching generally, or am
I likely to need to replace the tensioner? (ie, is the tensioner failing a
common problem). The belt looks fairly old (maybe even original, I haven't
had this car that long).


"Teknical" <teknical (AT) gmail (DOT) com> wrote

"Teknical" wrote

Spring-loaded tensioner? Should be indicator marks on it showing when the
belt has stretched enough to be replaced.