Intermittent whistling noise when driving. Goes when car steers left

[Med_tech3]

You may have read my other posts on my whistling noise. Firstly blaming the wheel bearing and then the gearbox. Anyway I now have more information. I have a 2008 C3 with auto gearbox. There is a whistling noise (sounds like someone blowing through reeds) that happens intermittently once the car has warmed up and when going above 60mph. It doesn't always occur but the new information is once it does occur, if I turn the steering wheel to the left, it disappears until I straighten the wheel. Also if it isn't happening, if I turn the steering wheel to the right, it makes the noise briefly. Could it be power steering? I think my C3 has electric power steering with a fluid reservoir. I have looked under the bonnet but can not see a power steering reservoir. Any help would be appreciated. Thank you

[xantia_v6]

My guess is that the noise is coming from a brake pad which is resonating due to light contact with the disk.

It could be due to a worn or sticky calliper, or a missing or damaged anti squeal shim or spring.

[Med_tech3]

Could be. I did take the car to a garage when the noise first started and they changed the discs and pads but I don't know the state of the calipers.

[Rp0thejester]

Okay, time for my stupid questions... Have you fitted anti brake dust guards on the wheels, any aftermarket thing fitted eg roof rack, good window seals all round? All body panels lining up correctly?

[GiveMeABreak]

1) Did you have the rear wheel bearings done in the end? This can sound like a low level humming at a certain speed.

2) As for Power Steering there is no fluid reservoir - the system is entirely electric and I've never known these to make any noise, especially a whistling.

[Med_tech3]

Thanks for your reply guys. I have not fitted any after market parts to the car and all body panels and undertray are fitted tightly. Marc - I didn't get the rear wheel bearings changed as I checked them again and they were ok.

I took the car for a drive and noted the noise disappeared when I turned the steering wheel to the left and also crucially when I pressed on the brake. It sounded like it was coming from the back near side wheel. When I got home I found the disc on that rear wheel was really hot whereas the one on the other back wheel was ok. I took off the hand brake, jacked up the wheel and turned it. It was very stiff to move and would stop almost instantly if you stopped spinning it. I checked the off side rear wheel to compare and that spun for a longer time.
I took the wheel off and investigated the brakes. I under the pad frame and found one of the slider bolts was stiff. I managed to pull it out and clean it up and grease it. i did the same with the other one. I tried to push back the caliper but I am not sure if it is stuck. I reassembled the brakes and put the hand brake on then off. The first time I took the handbrake off when the wheel was up (and I hadn't cleaned the brakes) the wheel was very hard to move. Now it moves a bit more but not as freely as the other side.
Is it worth changing the slider pins? Is it easy to remove the part that is stuck inside the brake pad frame? Is it worth replacing the caliper too? Is it easy to remove the brake fluid pipe and bleed the brakes after?

[ozvtr]

I took the car for a drive and noted the noise disappeared .............. when I pressed on the brake.

Ah, now if you had mentioned that earlier....

I took the wheel off and investigated the brakes. I under the pad frame and found one of the slider bolts was stiff. I managed to pull it out and clean it up and grease it. i did the same with the other one. I tried to push back the caliper but I am not sure if it is stuck. I reassembled the brakes and put the hand brake on then off. The first time I took the handbrake off when the wheel was up (and I hadn't cleaned the brakes) the wheel was very hard to move. Now it moves a bit more but not as freely as the other side.
Is it worth changing the slider pins? Is it easy to remove the part that is stuck inside the brake pad frame? Is it worth replacing the caliper too? Is it easy to remove the brake fluid pipe and bleed the brakes after?

You need to find out what the actual failure was.
The slider pins run in rubber and the grease can dry up and stop the caliper from "floating".
Moisture can get into the cylinder bore that the piston travels in. The piston can rust into the bore and stop moving.
However your rear hub is stiff and the above does not stop the wheel from rotating. It just stops the brakes from working.
Is the brake jammed? Are the friction pads constantly rubbing on the disc. Or as Marc said is it the wheel bearing?
If you can remove the brake caliper but the hub still does not spin freely, it's probably the wheel bearing.
If the hub is free with the caliper off it might have something to do with the wind out mechanism of the parking brake.

[Doo]

Thanks for your reply guys. I have not fitted any after market parts to the car and all body panels and undertray are fitted tightly. Marc - I didn't get the rear wheel bearings changed as I checked them again and they were ok.

I took the car for a drive and noted the noise disappeared when I turned the steering wheel to the left and also crucially when I pressed on the brake. It sounded like it was coming from the back near side wheel. When I got home I found the disc on that rear wheel was really hot whereas the one on the other back wheel was ok. I took off the hand brake, jacked up the wheel and turned it. It was very stiff to move and would stop almost instantly if you stopped spinning it. I checked the off side rear wheel to compare and that spun for a longer time.
I took the wheel off and investigated the brakes. I under the pad frame and found one of the slider bolts was stiff. I managed to pull it out and clean it up and grease it. i did the same with the other one. I tried to push back the caliper but I am not sure if it is stuck. I reassembled the brakes and put the hand brake on then off. The first time I took the handbrake off when the wheel was up (and I hadn't cleaned the brakes) the wheel was very hard to move. Now it moves a bit more but not as freely as the other side.
Is it worth changing the slider pins? Is it easy to remove the part that is stuck inside the brake pad frame? Is it worth replacing the caliper too? Is it easy to remove the brake fluid pipe and bleed the brakes after?

As per ozvtr, the brakes sticking is highly likely the cause of your noise. Going left, slows down the nearside rear wheel as does lightly pushing the brake pedal, so the tone changes.

With the pads dragging against the disc, the note produced can be heard as a low frequency hum. Sticking brakes can create all manner of annoyance including dust which burns into the lacquer leaving a lovely brown alloy wheel. Interestingly, it's the dust from the disc as opposed to the dust from the pads that does this! Extreme heat "can" warp the disc and even damage the bearings, but this is a case for glowing red discs.

Ensure you have good clean carriers as the build up of rust can also jam the pads in their beds and every time you push the pedal, they inch towards the disc, but don't return. I tend to use a grinder with a wire brush attachment (welding gloves and a decent set of wrap around protective eyewear is a must, along with a face mask to prevent inhaling dust and stop stray wires flying off the brush and impaling your skin Not the 1st time I've had a painful stabbing in the face and pulled out an inch of steel wire )

If you're handy with the spanners, you should invest in a good quality brake grease such as CeraTec or Brembo brake grease. A small brush (artists brush around 8mm is ideal) and dab a smear on the mating face of the carrier where the pad sits on. I do this every service and it slows down the build up of rust.

If you're at all unsure of the slider, probably best to replace them as it'll work out cheaper in the end.

Good luck