squealing noise

[smp009]

hi all in my 99 Vt commodore. all the rubbers have been replaced on the front.
but now there is a strange squealing noise coming from it when driving, not sure if it is wheel bearings? any help or information would be helpful please

thanks in advance

 

[dirty hands]

is the squealing noise in the engine bay
there are a lot of things running off the drive belt

 

[graham7773]

Last time I had this, my water pump seized solid after ignoring the noise for too long. Failing that, as dirty hands says, lots of things that rotate under the bonnet. Mechanics stethoscope, screwdriver and try to isolate the noise. Please don't place either instrument on anything that is turning. Just near each item.

 

[smp009]

Well the water pump I only 3 months old as the whole cooling system is new(water pump,radiator,thermostat). It sounds as if it is coming from the wheels

 

[s_ikari2015]

If you're handy with a spanner you can take the front wheels off and spin the hubs listening for noise. I'd suggest taking out the brake pads to rule out brake noise as you spin the hub. Wheel bearings make more of a scraping sound when they're old.

It could be a belt idler pulley. Easy enough to remove or loosen the belt and spin all the pulleys by hand. If any of them squeal, grind or rattle replace them otherwise they will eventually fail and shred the belt, causing problems like no power steering or alternator.

These are all cheap, as in free, things you can check. Wheel bearings come as a complete hub assembly, cheap and easy to fit. Pulleys are also cheap and easy to fit.

 

[Calaber]

The noise might sound as though it's coming from the front wheels but I'd check the drive belt idler pulley first. They are a common part that fails and the result is a high pitched squealing sound. Easy to determine if it's wheels or engine. You said the noise happens when driving. Does that mean it only occurs when the car is rolling or when it is stationary with the engine at idle as well?

If the noise occurs when the engine is idling but the car is stationary, remove the drive belt and start the engine. If the noise has disappeared, chances are it will be the idler pulley. You can spin them by hand and it will immediately be obvious which pulley is at fault - it will feel rough and "dry", because the grease has escaped past the seal and the bearing is stuffed. (I have removed the seal from the pulley on my VY and repacked the bearing, replaced the seal and the pulley has worked fine - it's the luck of the draw.)

If the noise only exists when the car is moving, remove the pads and see if a small stone or some other object is trapped between one of the pads and the disc. Check the condition of both sides of each disc to see if there is any obvious scoring which a stone etc would cause. While the pads are out and if there is no stone, spin each front hub slowly to see if it spins smoothly. Generally, a clapped out bearing will rumble, not squeal, and you can feel the roughness as you spin it.

Cheap pads will also squeal, but this is more noticeable when applying the brakes. Cheap pads are usually made of an extremely hard material that never seems to wear out, it just glazes over and the hard glazing squeals as it rubs against the disc. You can try to eliminate this problem by rubbing the pads on a smooth concrete surface to remove any glazing, then see if the noise is still there during a road test after the pads are reinstalled. If the noise has disappeared, you probably have cheap rubbish pads fitted which look best inside a dust bin. Hoik them and fit reputable pads. The rubbish ones will only glaze over again quickly and the noise will reappear.

 

[smp009]

Calaber
it is only whenthe car is rolling, and it only does it at 80 or above. iam thinking it could be the breaks, and alsothe brak pads are not expensive, but they where also notthe bottom of the barrel either. i am looking to get new rotors for it soon, and when that happens i will be putting Bendix performance pads on it.

thank you for your advice. very much appreciated

 

[Calaber]

Calaber
it is only whenthe car is rolling, and it only does it at 80 or above. iam thinking it could be the breaks, and alsothe brak pads are not expensive, but they where also notthe bottom of the barrel either. i am looking to get new rotors for it soon, and when that happens i will be putting Bendix performance pads on it.

thank you for your advice. very much appreciated

OK, I reckon it could be cheap, hard pads that have glazed over. Even though you say they are not bottom of the barrel jobs, some pads that are not the cheapest still suffer from glazing. It can also happen when you buy "High performance" pads, thinking they will give you better braking. Those pads are more fade resistant, but rely on being continually driven at higher speeds, such as motor sport, where the brakes get really hot and stay that way, and the glazing doesn't occur. They are generally not suited to road use.

Let us know how things go once you change the pads and discs. Make sure the replacement pads are suited to road use.