New Serpentine Belt
Super Member
Joined: Apr 2013
Posts: 1,029
From: South Carolina midlands
One tip on preventing serpentine belt squeal is to always replace the belt so it rotates in the same direction as previously installed. IOW before you remove a serp. belt, mark it with a Sharpie to indicate the direction of rotation. If it is easier, just mark 'top' on the belt if you don't know the direction of belt rotation. Also note the squeal you are hearing may be a pulley squeal , not a belt squeal. With the belt off, spin each pulley by hand.including the idler pulley and the belt tensioner to hear if there is a squeal.. Of course, this won't help in the case of a newly installed serpentine belt squeal. That means you have possibly a new belt problem, a pulley alignment problem or a squealing pulley problem.
Moderator
Joined: Nov 2007
Posts: 2,185
From: Zurich
Have fixed a lot of cars and trucks with squeals or squeaks or both. Neither of them came down to the belt.
Most of the fixes involved removing the belt and use brake cleaner to get rid of oil contamination. Then replaced the belt. Running ever since without so much of a noise.
The two others including my own Blazer was pulley bearings going bad.
A friend had a bad squeal and turns out one of the pulleys had been mounted the wrong way and was out of line with the crank pulley by just about 1 mm (hmmm - 1/25th of an inch). This has been found on several more such problems. Either the Alternator had been replaced and the bracket put on the wrong way, Tensioner pulleys where the bolt had been put in at an angle resulting in a Helicoil fix.
Very hard and old belts may do the same. Another friends car had about 30 percent of the ribs already broken off. They fall off in segments When we had the old belt off and warped it a bit and bent it a bit tighter than the pulleys would the ribs were just coming off. Rock hard rubber.
Then the belt itself. Even coming out of a store it can be already old. Had brand stuff being unusable while no name stuff that had been shelved for a decade was perfectly fine. Depends all on the storage.
AC Delco has been fine for at least 3 replacements on my Blazer.
Most of the fixes involved removing the belt and use brake cleaner to get rid of oil contamination. Then replaced the belt. Running ever since without so much of a noise.
The two others including my own Blazer was pulley bearings going bad.
A friend had a bad squeal and turns out one of the pulleys had been mounted the wrong way and was out of line with the crank pulley by just about 1 mm (hmmm - 1/25th of an inch). This has been found on several more such problems. Either the Alternator had been replaced and the bracket put on the wrong way, Tensioner pulleys where the bolt had been put in at an angle resulting in a Helicoil fix.
Very hard and old belts may do the same. Another friends car had about 30 percent of the ribs already broken off. They fall off in segments When we had the old belt off and warped it a bit and bent it a bit tighter than the pulleys would the ribs were just coming off. Rock hard rubber.
Then the belt itself. Even coming out of a store it can be already old. Had brand stuff being unusable while no name stuff that had been shelved for a decade was perfectly fine. Depends all on the storage.
AC Delco has been fine for at least 3 replacements on my Blazer.
BF Veteran
Joined: Jan 2007
Posts: 4,625
From: Florida
Have fixed a lot of cars and trucks with squeals or squeaks or both. Neither of them came down to the belt.
Most of the fixes involved removing the belt and use brake cleaner to get rid of oil contamination. Then replaced the belt. Running ever since without so much of a noise.
The two others including my own Blazer was pulley bearings going bad.
A friend had a bad squeal and turns out one of the pulleys had been mounted the wrong way and was out of line with the crank pulley by just about 1 mm (hmmm - 1/25th of an inch). This has been found on several more such problems. Either the Alternator had been replaced and the bracket put on the wrong way, Tensioner pulleys where the bolt had been put in at an angle resulting in a Helicoil fix.
Very hard and old belts may do the same. Another friends car had about 30 percent of the ribs already broken off. They fall off in segments When we had the old belt off and warped it a bit and bent it a bit tighter than the pulleys would the ribs were just coming off. Rock hard rubber.
Then the belt itself. Even coming out of a store it can be already old. Had brand stuff being unusable while no name stuff that had been shelved for a decade was perfectly fine. Depends all on the storage.
AC Delco has been fine for at least 3 replacements on my Blazer.
Most of the fixes involved removing the belt and use brake cleaner to get rid of oil contamination. Then replaced the belt. Running ever since without so much of a noise.
The two others including my own Blazer was pulley bearings going bad.
A friend had a bad squeal and turns out one of the pulleys had been mounted the wrong way and was out of line with the crank pulley by just about 1 mm (hmmm - 1/25th of an inch). This has been found on several more such problems. Either the Alternator had been replaced and the bracket put on the wrong way, Tensioner pulleys where the bolt had been put in at an angle resulting in a Helicoil fix.
Very hard and old belts may do the same. Another friends car had about 30 percent of the ribs already broken off. They fall off in segments When we had the old belt off and warped it a bit and bent it a bit tighter than the pulleys would the ribs were just coming off. Rock hard rubber.
Then the belt itself. Even coming out of a store it can be already old. Had brand stuff being unusable while no name stuff that had been shelved for a decade was perfectly fine. Depends all on the storage.
AC Delco has been fine for at least 3 replacements on my Blazer.
ive had good luck with Gates and Dayco. I just changed out a Dayco on my Toyota while I was doing a water pump that looked good after 110,000 miles. In this case the noise was the water pump bearing.
George
New Member
Joined: Oct 2019
Posts: 85
@error-401 - Nice set of tips - I had forgotten about the contaminated pulley one. The old belt shredded on the "new to me" used vehicle. Actually driving it home from the BMV for titling - LOL...
The belt did not squeal on test drive or the 5 miles to the BMV. But dirty/slipping pulleys is definitely a possibility. For now it's gotten about 400 miles on the new belts and they've stopped squealing so I will keep them on the "watch" list.
The belt did not squeal on test drive or the 5 miles to the BMV. But dirty/slipping pulleys is definitely a possibility. For now it's gotten about 400 miles on the new belts and they've stopped squealing so I will keep them on the "watch" list.
Thread
Thread Starter
Forum
Replies
Last Post
racsan
2nd Generation S-series (1995-2005) Tech
1
Apr 24, 2011 07:38 AM
