My car has developed a whiney noise that becomes higher pitched the faster I go. I first thought that it might be notorious M32 gearbox (see my previous thread) but as it doesn't seem to be gear related, I'm beginning to doubt that. Namely, it starts at just over 2K RPM and becomes more high pitched the faster I go. The sound remains the same no matter what gear I'm in (or out, I've tried it with clutch depressed). No whiney noise when revving when stationary. I had the cam belt and tensioners, water pump and aux belt changed last year - could it be related? Or could it be alternator? Any ideas welcome. The garage that changed cambelt thinks it needs a new gearbox, but it sounds a bit excessive (and expensive) as a first problem resolve.

Melanabb said:

No whiney noise when revving when stationary.

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Hi Mel

That effectively rules out alternator, water pump, cambelt, auxiliary belt; ie all the stuff you had changed last year.

If it's the same in all gears, that probably rules out the layshaft bearings in the gearbox (the most common M32 problem, from what I've read).

I'm thinking wheel bearing, driveshafts, differential, maybe the output side of the gearbox. I'm hoping wheel bearing, as that's the easiest & least expensive out of that lot.

Interestingly this happened to me about 20 years ago - several very experienced mechanics had bet their shirt on it being the diff (& that was my first thought too), but when I stripped it down it turned out to be a noisy nearside front wheel bearing. Interestingly there wasn't the slightest bit of play anywhere in the offending wheel.

A couple of things you can try:

1) What happens to the noise if you're going downhill & drop the car into neutral?

2) At cruising speed in 5th & 6th, try lightly holding the gearstick & alternately lifting off and accelerating. If it's a gearbox bearing, you'll likely feel the gearstick move in your hand when you lift off.

Next step for me would be to jack up the front & thoroughly check the wheel bearings & driveshafts for excessive free play. A friendly indie might be prepared to do that for free or beer money.

Be careful not to assume it must be the gearbox just because it's a well known weakness with that car.

Prior to getting my daughter her punto she had a Citreon C3. One day I get a call to say the cars developed a noise. Being 17 miles away I advised her to take to a local inie placed who eventualy diagnosed the gearbox to be gone.Hmmmmm...


A few days later when she was at mine I took it out and thought the car was terminal!..no play in the bearing using the usual 'hold the wheel in the 9+3 position or the 12+6 position. Definate whine/grumble tho when in gear.


A local specialist breakers yard jacked the car in the air,on one side and then in gear...wheel bearing collapsed!!!

jrkitching said:

Hi Mel


1) What happens to the noise if you're going downhill & drop the car into neutral?

2) At cruising speed in 5th & 6th, try lightly holding the gearstick & alternately lifting off and accelerating. If it's a gearbox bearing, you'll likely feel the gearstick move in your hand when you lift off.
.

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1) Noise still the same, no change in whine frequency going downhill or neutral. Getting higher pitched the quicker I go though (tried higher gear, lower gear, no gear - all the same whine)

2)Tried that, no movement in the gearstick either accelerating or lifting off. No movement in the gearstick while changing up or down into any gears.


Trip to Fiat specialist tomorrow I think...

Melanabb said:

1) Noise still the same, no change in whine frequency going downhill or neutral. Getting higher pitched the quicker I go though (tried higher gear, lower gear, no gear - all the same whine)

2)Tried that, no movement in the gearstick either accelerating or lifting off. No movement in the gearstick while changing up or down into any gears.


Trip to Fiat specialist tomorrow I think...

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Usually with the classic M32 bearing failure issue you can feel it quite clearly through the gearstick. I'd agree with you that suspicion is moving away from the gearbox.

I'm still thinking wheel bearings or driveshaft - as they're all connected, it can be surprisingly difficult to pin down exactly where the noise is coming from. It might be possible to reproduce it by jacking up both front wheels and spinning it up by hand with the car in neutral; much easier both to do and to listen for if the brake pads are removed.

This next one is a bit obvious, but has anyone checked the gearbox oil level?

Mel, does the noise intensity change when you corner? as usually if it is a wheel bearing the more load you place on it affects the sound. i.e. if you turn to the left the weight transfers to the offside and vice versa.

Thanks guys, really appreciate your help.

Jrkitching, I haven't checked the oil in the gearbox, thats on my list for the mechanic tomorrow. I'll get them to jack the car up and test for wheel play too.

Tony, I've heard the wheel bearings fail on youtube, doesn't sound the same. Also, there is no extra noise while swerving left or right. Hopefully jacking up will reveal more...

The mystery continues...

Btw, I have to say that the noise was audible for hmmm... let me think, more than 9 months but I thought I was imagining things as I usually listen to the motor rather than music in the car, but when my 8 year old daughter said the other day "mummy what is that whiney noise in your car?" I realised that I'm not completely mad Saying that, its not deafening - you might miss it if you are not trying to hear it (if you know what I mean...)

garage should pin-point it,

we did ours by the wheels running free method,
made worse to identify by diesel clatter,

unfortunately garage tasked with changing offending bearing... messed up ABS ..!!:bang:

Charlie

Mystery deepens... Trawled through Youtube yesterday trying to find the same sound and after many, many hours of funny car noises I've found this



My car sounds exactly the same! I'll try to record it and post it today so we can compare. It doesn't bode well for my gearbox at the mo...

In my experience, if it were a wheel bearing, you would have noticed the noise getting worse over a 9 month period.
However, having said that, if you can pinpoint the noise to any one side, then changing the wheel bearing would be my first line of attack, as it's the cheapest option.

Cupped tires, (sawtooth tread), very common, and often the wheelbearings got the blame, sounds almost alike.
See a tire specialist, and have your tires checked for cupping....

Peter Pick-Up said:

Cupped tires, (sawtooth tread), very common, and often the wheelbearings got the blame, sounds almost alike.
See a tire specialist, and have your tires checked for cupping....

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As in tyres that have been run under inflated for a long time?

nikrox said:

As in tyres that have been run under inflated for a long time?

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No, it happens with tires that are inflated by the book....

Or when a shock absorber isnt doing its job properly

Tire cupping can happen with perfect shockabsorbers, it's kind of modern mystery why some cars and some tires have it, while others don't....

Yeah thats why i said or, i didnt say it was the main cause for it

When last year was your cambelt changed?

I had virtually the same issue which was caused by the cambelt being overtightened, which wore out the bearings in the waterpump and tensioner.

Cambelt (inc. aux belt and water pump) was changed last March. As I understood the noise can't be from the cambelt as its not present when the car is stationary?

Update: the garage found the worn wheel bearing (plus a coolant leak as a separate issue) but are still adamant that the noise is coming from the gearbox. I'm picking up on Friday so we'll see if its still present after the wheel bearing repair.

Many thanks for all your help. Will keep you posted...

It was present in mine when stationary, just harder to hear.

Where is the coolant leak?

Tbh id be surprised if it was cambelt related as the noise would have started quite soon after it was changed

Melanabb said:

Cambelt (inc. aux belt and water pump) was changed last March. As I understood the noise can't be from the cambelt as its not present when the car is stationary?

Update: the garage found the worn wheel bearing (plus a coolant leak as a separate issue) but are still adamant that the noise is coming from the gearbox. I'm picking up on Friday so we'll see if its still present after the wheel bearing repair.

Many thanks for all your help. Will keep you posted...

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Thanks for the update Mel.

I'll keep fingers & toes crossed for you that replacing the wheel bearing fixes the whine.

I think the cambelt is a red herring.