Hi all, I have a 455 in my cutlass that was originally a 350. I have the pulleys lined up perfectly but the alternator belt still squeals. I know it is this belt because back when I couldn’t get the car to charge I just pulled the alternator and belt out and ran the car off the battery, with no squeal during revs. Is there any fix for this belt squeal? It’s horrendous.

 

I'd try a new belt, make sure the tension is OK, and then if all else fails, spray some belt dressing on it (assuming they still make that stuff).

 

What brand of belts are you using?

 

Is there possibly something wrong with the alternator that is putting too much drag on the belt and causing it to slip ?

 

Did you tighten the alternator belt correctly?

https://classicoldsmobile.com/forums...pulley-139553/

https://classicoldsmobile.com/forums...t-loose-51844/

 

Belt size, condition and quality really matter. The belt must be the correct width and length. The width is often overlooked. If the belt is down in the pulley it is probably too narrow. Look at the sides of the belt for glazing.

Good luck!!!

 

What accessory brackets did you use for the swap? What pulleys? Did you get both spacers correctly installed between the PS pump bracket and the block?

 

I'm having the same issue on my 350 - Initially had start-up squeal that would last for a couple of early park-idle throttle blips before going away. Adjustments to the existing belts didn't cure so I replaced all 3 with new Gates XL and readjusted each applicable component tension (A/C compressor, p/s pump, alternator). Compressor is a Sanden for the Vintage Air system, alternator is a Powermaster 100 amp (si series internal regulator).

All pulleys properly aligned and clean

No free-spinning pulley problems or voltage issues with the alternator day or night.

Now I seem to have eliminated the start-up squeal but it's occurring at higher RPM ranges somewhere approaching 3k.. Frustrating...

 

I too am running Gates XL belts on my '72 U code Supreme with the EXACT same issue. I've tried everything listed above and Ive given up on the Gates and am gping to switch to AC Delco. Will keep everyone posted.

 

I installed new Gates altenator and power steering belts on my 66 Cutlass. No problem with the the altenator belt however the power steering belt really squeked. I finally was able to put enough tension on the power steering belt and the squeal is gone. It takes a lot of leverage on the power steering belt set up to get the least amount of belt deflection of 1/2 inch. Runs fine now with no squeaks for the last month.

It wasn't the belts.

Wayne

 

That may be true in your case, but I can tell you that I didn't have an issue until after I installed the Gates belts. After having enough of enough, I removed the belts, cleaned the pulleys, bought new Gates belts, and followed the tightening sequence of the ps belt to the letter, after of just about a month of driving, the squeal was back. I tried re-tightening the alternator belt just to make sure, and it didn't help. So, as I said, I'm done with the Gates belts.

 

It’s been my experiences every time a belt squeals it’s because it’s too loose - every single time. When a belt which has never squealed on piece of equipment begins to squeal it’s because the belt has stretched and has lost tension and it’s time for a new belt. I’ve bought replacement belts which were unsatisfactory and started squealing - a couple disintegrated in very short order. On those occasions I carefully reviewed the characteristics of the belts. They did not seat low into the pulley grooves - they were riding far too high and literally continuously slipping. Wrong belts for the application for whatever reason - mislabeled, bad manufacturing or whatever. My point is they were not tight enough. Be sure your belts sit deep into the pulley grooves and are very tight - they should not ride high in the grooves, if they do they will continually slip and squeal like an old stretched out belt.

 

Did you try tightening the belt that was squealing? Tightening the alternator belt doesn’t do anything to address the power steering belt tension.

 

I would tend to agree in principle that tighter is better but in practice, not always the case. I've tightened my brand new belts to the most minimal deflections possible and all it's done for me is shift the squeal threshold from occurring at start-up to occurring at speed during moderate accelerations approaching 50-60mph.

and at this point I don't want to attempt further tightening for risk of stressing component bearings - so I'll give it some time and maybe swap out to different belts again if no change in status.

 

A squealing belt is slipping because it’s too loose. There’s reasons it can be slipping (not enough tension), but it’s never because it’s too tight. And, when it’s slipping it’s definitely heating up.

 

Accessories--they seem to always be problematic....

 

in my case, it's the alternator belt, and yes, it is properly adjusted.

 

Update: I installed the AC Delco belts and after three runs all is well...not a peep from the belts👍

 

Thanks all,

I ended up solving the issue, I just needed to include the crank pulley in the belt routing. Went with all gates and a 7535 alternator belt. No more squeal

 

I have a variation on this but the belt will only squeal when the engine is good & hot at speeds above 3,000 RPM. 69 Cutlass S convertible with the Rocket 350. Factory A/C car but AC compressor has been removed. I haven't tried the screwdriver behind the P/S pump pulley yet. How tight should it be? It seems my belts are pretty tight but, obviously something is amiss.

 

Firstly ensure you have the correct belt - a belt which rides into the "V"alley of the pulleys - not a belt which rides too high above the "V"alley. An improper belt (esp. one which rides too high) will often tend to produce a squeal as it does not "fit" into each pulley "V"alley.
Secondly, addressing how tight it should be, you can tighten these belts "a lot". Use the screwdriver method. You should have no more the 1/2" deflection (up & down & laterally). With your hand/fingers at the mid-point of the length of the belt, you should not be able to turn (twist) the belt greater than 1/2 turn.

 

I've checked the deflection but not the twisting. The free span between water pump & power steering is quite short. I'll get a suitable screwdriver & give it a try.