Squeaking Drive Belt VS V6 commodore

[Changa]

Ok so my engine belt is squeaking, now before you say replace the belt I have gone through three belts already, all doing the same thing. I thought the belt was slipping so I put some belt grip onto the pulleys, its only got worse. So I am guessing the belt is actually gripping too much because when I lubricate the belt and pulleys the noise disappears. This only fixes it short term though because as soon as the belt dries out it starts to squeak again. By the way I had a mechanic look at it and they looked at every pulley replacing the bearings in the suspisious ones. Heard someone say while I was there (another mechanic) that he had been having alot of trouble with squeaking belts like they had changed the compound used for making the belts. I am currently using the repco brand of drive belt called dayco, the first belt that started squeaking was a gates racing belt, so the squeaking isnt confined to one brand of belt. Just wondering if there is a way to keep the belt 'supple' and 'moist', by some form of lubrication that doesnt have to be applied like every day, like some kind of grease that doesnt just melt and drip off.

[tt460]

sounds like a bearing, try spraying 1 bearing at a time with wd40 and find what bearing is making the noise.

could also be be slipping on a pulley and the pulley needs roughing up with some sandpaper to help it grip.

[Changa]

As I said before the mechanics looked at all the bearings and pulleys for the problem and replaced any dodgey ones and it still squeaks. The thing is, I dont think its slipping, because I put some belt grip stuff on there and it just made it 10 times worse. But when I put on some silicon spray (lubricant) onto the belt and pulley ribs the noise disappears. Its almost like it grips too much and makes a noise and when lubed it stops it.

[tt460]

Just try what i said with spraying the bearing on the pulleys one at a time. it will take 10 mins max and you already have silcone spray so its not going to cost anything.

[Changa]

Lol yeah I have done what you said about 8 times before, it doesnt really help at all. It does stop the squeaking but only coz the lubricant drips onto the belt making it moister and more supple. Its like the belt grips too much and needs to be lubed.

[88GreenVN]

Run some candle on the belt while running the car. Worked for me on my VS.

[Changa]

Yeah the noise seems to have gone for 2 days after spraying that silicon spray on the belt and the pulleys.

[Nadroj]

Harking back to the days before German designed Holdens, there was a model (forget which) with a Red straight six motor that also had a common fault of squealing belt - the fanbelt as it was called those days.
The cause was a pulley that hadn't been machined deeply enough, so that the belt would often ride on the bottom of the Vee, rather than on the sides. That led to slip and noise. The fix was to remove the offending pulley and machine the Vee deeper on a lathe.
So, could this fix be applied to a Commodore's serpentine belt? It has many small Vees, but essentially it is still a V-belt. The belt could still feasibly ride on the bottom of the grooved Vees on a pulley, especially if it was worn. But, machining several grooves wouldn't be so easy as with the single Vee pulley. So, rather than deepen the pulley grooves, I removed a small amount of rubber from the tips of the belt itself. Method: Stapled a strip of abrasive cloth to a piece of flat timber, and with the engine idling, rubbed it in a position where it was going over an idler pulley, ribbed side out. A minute or so of this treatment, and 4 days later still no squeaks. Wunderbar!
Jordan

[hako]

Serpentine belts do not rely on "Vees" to grip as they do not have "Vees" like the old "V" belts...instead they have ribs with straight edges which increase the surface area of the belt in contact with the pulley improving grip plus they are designed to wrap around the pulley.
It's possible for squeaking to occur when the ribbed pulley is not in perfect alignment with the serpentine belt...this can be checked by placing a flat ruler/edge against the front edge of the pulley and checking that it runs in the same plane as the belt.

[Nadroj]

Where are you getting this information, hako? It's not correct.
Multi-ribbed belts have the same angled sides as single Vee belts - 40 degrees included angle. I dare say an old single Vee belt is also designed to wrap around a pulley!
See picture of some multi-vee pulleys that I made for an old bike. I used the info on the table to make them. You can also check Machinery's Handbook for detailed specs.
Jordan

[strgas]

try some graphite powder on the belt to deglaze the pulleys and belt surfaces

[stuntmanmike]

My dodgy quick fix is to hold a bar of soap to the belt while the engine runs on idle and just lightly apply the dry soap to the underside and the top side of the belt. A quick second or two is enough. Cheapo stuff from hotels works better than your happy hands stuff for perfumed soft skin.

I’m no mechnik and I thinks the squeaking is a result of the rubber behaviour as it passes over a pulley with the leading edge compressing as the angle of wrap increases and then releases. Just like a car tyre as the contact patch rolls on the road but not as pronounced. The side walls of the belt may be rubbing on the pulley walls too.

Think of the shape of an eraser when you push it on a hard surface and then release the pressure and then pull it to stretch it. Marvel at how it changes shape.

It could be a bit more complicated than that depending on a few things like… if this is a harmonic result from two pulleys being close together with surging rpm on idle... or whether the combined factors lead to belt pulsations at various engine speeds.

Friction! That frictional behaviour maintains grip between the contact surfaces of the belt and pulley. That also explains why the pulleys become warm/hot after a good blat down the road. Especially if there is any bearing resistance in any pulley or rapid changes in the angular acceleration of the crankshaft pulley (like with a lumpy cam or a missing/surging idle).

Anyway I hope that helps and shines some light on what the problem could be. Rubber compounds change with heat and time so a fresh belt could be more flexible and prone to vibrations than an aged, heated and stretched one. Just remember that oil chews rubber in no time and lubricates surfaces. Not a good thing for long life.

Enough ranting from me and good luck with finding a solution that works for you.

[Nadroj]

Quick fixes like soap or whatever that temporarily change the coefficient of friction (grippiness) will stop being a fix as soon as it wears off. Reportedly, around 3 days.
However, if the idea of adding stuff to improve grip appeals, there is some product that is designed for the job, like:
<http://www.crcind.com.au/catalogue.nsf/web_brands/Belt+Grip?openDocument>
It's a kludge, but quick and effective for a while. Used car dealers take note
I'm sticking to my guns, and suggest the cause of the belt squeal is that it is bottoming in the pulley grooves, producing slip and noise. My fix is to remove a bit of the rubber at the tips of the vees, by abrasion as mentioned before. It's real quick!
Jordan

[95 vs stato]

Vegetable cooking oil in a spray can has worked on all types of belts for me so far.

[RX25SE]

Reading hako's post (#9) I tend to agree with the alignment issue.
VS and VT seem to have issues with the tensioner assembly wearing out. Not the pulley, but the pivot of the spring loaded arm.
When the pivot wears, it causes the tensioner pulley to go out of alignment.
Mine is worn (no squeaking) but it produces a knocking sound not unlike a crook harmonic balancer. From inside the car it sounds like a dodgey main engine bearing!

If all else fails, and it sounds like it has, replace the tensioner assembly. You will need to drain the coolant as the heater hose pipe must be removed (fit a new 'O' ring).
Use a genuine GM item as I have seen the aftermarket units fail with little use.

I'd be interested to hear what the fix is.

Good luck!

[Nadroj]

RX...
To be clear, are you saying that misalignment of a pulley causes squeaking, but not in your case?

Jordan

[IBLOWN]

Forget all this bs, go to holden and buy a VT steel idler pulley. The one under the DFI module. The plastic pulleys have a crappy bearing.

Spray some WD40 in the little opening on top of the idler tensioner and work it up and down about 20 times.

The bearing in that idler pulley starts to wear. The tensioners spring starts to wear or needs lube and doesnt have enough tension to pull the belt firmly enough to take up the looseness of the bearing in the idler pulley.

Before you do anything start the car, put a 15mm socket on the idler tensioner and put a bit more tension on it with the ratchet. If the noise goes away then do what i said.

[RX25SE]

RX...
To be clear, are you saying that misalignment of a pulley causes squeaking, but not in your case?

Jordan

It may cause it. The arms do seem to wear out.

The above post may be worth a shot to diagnose a dud tensioner.

I've lubed my tensioner arm with a viscotene type spray but the knocking is back after about 2 months.

[IBLOWN]

Yeah thats right. I meant to say try that with the lube, if it works then replace the tensioner. Its just another way to diagnose the tensioner.

[Nadroj]

Forget all this bs, go to holden and buy a VT steel idler pulley.

Before you do anything start the car, put a 15mm socket on the idler tensioner and put a bit more tension on it with the ratchet.

Good suggestion about putting extra tension with a spanner - wish I'd thought of that, just to give more evidence the noise comes from belt slip.
Note that I'm not doing armchair diagnostics with my "sandpaper" treatment. I did it, and it fixed the squealing - no bullshit!
A new tensioner spring may well have also stopped the squeals.

Jordan

[ubayIT]

I have just run into the same problem after a belt change. Wearing down the tops of the V's on the belt using sandpaper on a stick did the trick. My mechanic confirmed that only belts from BOSH have the same width ribs as the original belts. The rest of the aftermarket ones have thinner ribs which leads to vibration of the belt causing that horrible squealing. I also sprayed some belt grip on to counteract the WD40 I'd put on when checking the pulleys. I did find a bad bearing in one of them but it wasn't the cause of the noise.