350 chevy belt squealing

**blueline15** · #1 (**permalink**) 08-09-2010, 03:57 PM

okay, lets here your opinions.

bought a 1987 Chevy 1500 pick-up truck with 5.7 FI and 3 speed manual. for the first few months the belts never squealed.

a few weeks ago, some work was done on it in perperation of my 1900 mile drive from washington to michigan. part of that work included changing the main belt (435 belt) that comes off the crank pulley and drives the water pump, altenator, and fan. the belt that drives the power steering pump was also replaced, but i know thats not the belt that squeals. the belt that drove the a/c compressor was removed as the a/c system doesnt hold vacuum, so no need to be running the compressor.

work also done was was a new thermostat and radiator hoses, and a new water pump, as the old one was leaking.

at first after the work, the truck never squealed. it was about 800 miles into our trip the truck would squeal when first started, every time, and as the engine RPMS came down, the squeal went away, then would squeal again at the top of first gear, until shifted into second gear. it seems it squeals longer and longer after first started.

tried a new belt from napa today and didnt change anything. the guy at napa suggested taking some 280 or 300 grit sandpaper to the pullies to roughen them up, as the heat from driving so long may have glazed the pullies. sounds like a legit solution?

also, is there an adjustment when installing the water pump, or is just straigt thru bolt holes? because im thinking maybe the water pump pulley isnt lined up anymore causing it squeal?

any ideas or solutions? anybody have experience with this? thanks in advance.

tt425 · #2 (**permalink**) 08-09-2010, 06:04 PM

Quote:

Originally Posted by blueline15

okay, lets here your opinions.

bought a 1987 Chevy 1500 pick-up truck with 5.7 FI and 3 speed manual. for the first few months the belts never squealed.

a few weeks ago, some work was done on it in perperation of my 1900 mile drive from washington to michigan. part of that work included changing the main belt (435 belt) that comes off the crank pulley and drives the water pump, altenator, and fan. the belt that drives the power steering pump was also replaced, but i know thats not the belt that squeals. the belt that drove the a/c compressor was removed as the a/c system doesnt hold vacuum, so no need to be running the compressor.

work also done was was a new thermostat and radiator hoses, and a new water pump, as the old one was leaking.

at first after the work, the truck never squealed. it was about 800 miles into our trip the truck would squeal when first started, every time, and as the engine RPMS came down, the squeal went away, then would squeal again at the top of first gear, until shifted into second gear. it seems it squeals longer and longer after first started.

tried a new belt from napa today and didnt change anything. the guy at napa suggested taking some 280 or 300 grit sandpaper to the pullies to roughen them up, as the heat from driving so long may have glazed the pullies. sounds like a legit solution?

also, is there an adjustment when installing the water pump, or is just straigt thru bolt holes? because im thinking maybe the water pump pulley isnt lined up anymore causing it squeal?

any ideas or solutions? anybody have experience with this? thanks in advance.

The first thing you need to check out is to see if you have the right water pump. A micro groove belt should never squeak. Make sure the nuts that hold the fan clutch and pulley to the water pump are tight. The water pump just bolts straight up. Check for a loose belt and also check and make sure all adjustment bolts are tight. I work at a CARQUEST AUTO PARTS and have been in auto parts for over 21 yrs. I am not that old just got into auto parts before I got out of high school. I will be glad to assist you if I can. Thanks

tt425 · #3 (**permalink**) 08-09-2010, 06:24 PM

Also check and make sure the belts are straight. The v-groove pulleys may be worn out see if you have any wear on those pulleys. Its about like a clutch pulley an a atv if it wears down it will cause the belt to squeak. Also I think somebody poured something in that NAPA guys coffee this morning if he thinks sandpaper will cure the problem.LOL. Also antoher myth in auto parts "My belt stretched". WRONG the sides on the belt wore out causing the belt to ride deeper into the pulley. Giving the appearance that the belt stretched. One more thing if a belt is too tight it will also squeak. Thanks. Tell us what you find out.

bukaty · #4 (**permalink**) 08-10-2010, 02:39 PM

Did the 87' 350 have the serpentine belt? I had an 89 3/4 ton van that absolutely drove me nuts with a squeaking serpentine belt. I could put a new one on it and it would stop for about 30 to 90 days then it would start all over again.

I don't recommend this, but out of sheer anger one day I took my sandblaster out to the truck, removed the belt and blasted the crap out of the pulley's. Yes they were glazed and polished. I put a new belt on it shot it with a rattle can flat black. It never squeaked again. Sandpaper idea sounds like it might work. I'd hit it with some 120 grit and see what happens

**blueline15** · #5 (**permalink**) 08-10-2010, 02:46 PM

any idea how tight or how loose that belt should be. using only a screwdriver for leverage i still have between 1/4 and 1/2 of play up and down on the belt between the fan and altenator pullies, im thinking it might be too loose. i was going to try to get that tighter to see if that helps, without jacking all the pullies up.

ill check the pullies while im at it

....no serpentine belt, its the old style, three different belts, no idle tension pully

tt425 · #6 (**permalink**) 08-10-2010, 03:05 PM

on a 1987 oem 350 had a serpentine belt on the alternator belt. So someone has changed some things on this truck.I would say about 1/4" of play in the belt is right. Look real good and make sure they are running straight. Thanks

tt425 · #7 (**permalink**) 08-10-2010, 03:08 PM

Quote:

Originally Posted by bukaty

Did the 87' 350 have the serpentine belt? I had an 89 3/4 ton van that absolutely drove me nuts with a squeaking serpentine belt. I could put a new one on it and it would stop for about 30 to 90 days then it would start all over again.

I don't recommend this, but out of sheer anger one day I took my sandblaster out to the truck, removed the belt and blasted the crap out of the pulley's. Yes they were glazed and polished. I put a new belt on it shot it with a rattle can flat black. It never squeaked again. Sandpaper idea sounds like it might work. I'd hit it with some 120 grit and see what happens

1986 and 1987 Chevy 350 truck engine had a serpentine belt on the alternator and the other belts were v-groove. Thanks

**blueline15** · #8 (**permalink**) 08-10-2010, 07:39 PM

tt, im not sure i have my terminology right.

the other two belts are v-belts, but this belt is a #435, its fairly flat and has 4 or 5 ribs on the back side, and runs from the crank pulley around the water pump, fan, and altenator. i need to mesure it but i bet the play is closer to 1/2 inch or so

tt425 · #9 (**permalink**) 08-11-2010, 04:24 AM

Quote:

Originally Posted by blueline15

tt, im not sure i have my terminology right.

the other two belts are v-belts, but this belt is a #435, its fairly flat and has 4 or 5 ribs on the back side, and runs from the crank pulley around the water pump, fan, and altenator. i need to mesure it but i bet the play is closer to 1/2 inch or so

That flat belt is a serpentine belt. I think a 1/2" of play may be to much. You may want to tighten it some. Thanks

Wolfman · #10 (**permalink**) 09-27-2010, 11:51 AM

If the belt is a surpentine belt check the tensioner. The bearing goes bad and they will squeal, really easy fix. To check it, take the tension off the belt and see if there is any play in the tensioner pully or if it feels rough when you turn it.

The spring loaded tensioner sets the play on the belt by spring tension there is no other adjustment on it.