1998 Chevrolet Blazer squeaking under hood

DKENT74

MEMBER
1998 CHEVROLET BLAZER
4.3L
6 CYL
4WD
AUTOMATIC
171,000 MILES

I HAVE HAD A SQUEAKING NOISE UNDER MY HOOD THAT IS DRIVING ME NUTS. I HAVE REPLACED THE BELT, ALTERNATOR, AND TENSIONER. EACH REPLACEMENT WAS FOLLOWED BY ONE DAY OF SQUEAK FREE DRIVING ONLY TO HAVE IT RETURN.

I HAVE TAKEN THE BELT OFF AGAIN AND TURNED PULLEYS USING MY HAND. I HAVENT BEEN ABLE TO DETECT THE SOURCE.

COULDN'T IT BE THE WATER PUMP BEARINGS?

1 Reply

CARADIODOC

MECHANIC
33,738 POSTS

Squealing is caused by a tipped or turned pulley, most commonly an idler pulley. If it's caused by bad bearings in the generator or water pump, you'll feel that right away when the belt is off.

Sight down along the upper pulleys to the lower ones, and look for one where the side of the belt is peeking out as little as 1/16". If you see that, the belt has to walk across that pulley as it goes around it, and that's what sets up the squeal. Either that pulley or the one right before it is turned or tipped.

If there was any kind of belt dressing used on the previous belt, remove the new belt to save it for an emergency repair, scrub all the pulleys with engine degreaser and a brush, then install a new belt. No belt dressing must ever be used on a serpentine belt. Dirt and road dust will stick to it and become embedded in the smooth back side of the belt, and you'll never solve the squealing.