Technical Strange sound while driving

[MegaVat30]

[USER][/USER]Hi fellows Seicento drivers.
During a regular trips my car began to make a strange high pitched sound that comes from under the hood. The sound is not constant, it appears at any time and disappear just as suddenly. Most often it is heard at a speed higher than 100 km. During the appearance of the sound I can completely remove my foot from a gas pedal and also when I press the clutch pedal sound will not disappears. Sound stops when I brake. The rest of the time I drive without it.
Maybe it's a rock? What could it be?

Audio recording is attached. (Remove spaces)
h t t p s://clyp.it/lvdmxn0b

 

[purf]

It sounds like you have a jet engine!

I have never heard anything like that. Seems very high pitched.

Brake splash shields touching the brake disk? Or brake related?

 

[MegaVat30]

Visually, the brakes look normal (like everything else, the brakes work fine, too). I also stopped by at a service station and I was told that there were no problems with my car.
Unfortunately the sound appears only at high speeds and disappears when I brake, so I can not get out of the car and listen where the sound comes from.

We'll have to take my car to a complete diagnosis. I will post if I find out something new.

 

[Metalguru3]

Water pump/timing belt tensioner bearings?

 

[purf]

Good point - could be water pump or timing belt idler - when the pump went on my previous cinq it made a high pitched whining but it was not very loud over the engine. I saw an old punto in the scrap yard with a failed cam belt idler bearing last week so it does happen.

Could also be the alternator bearings? My Sei has had quite a noisy alternator if its left for a couple of weeks without being driven. Try some WD40/GT85 on the alternator? (be careful not to get any on the alternator belt)

You say the sound continues when the engine idles as you are traveling over 100km/h. I guess that means that it must be either a wheel bearing, drive shaft/gearbox or the brakes? Usually wheel bearings make a rumbling noise, and driveshaft CVs make a cracking banging noise. So this perhaps indicates the brakes?

Free brake checks usually only work for the garage - when they find you need new parts...

How many miles has it done?

You could try putting it in 5th gear with the wheels safely off the ground? Then you can tell if its the coming from the front or back wheels? Although I cant remember if both wheels will turn in this situation - maybe you'd need a rolling road?

 

[Metalguru3]

Where are you?
im sure you could pop over to someone who could have a look for you
for what its worth im in Tamworth and would be happy to look at your car

 

[MegaVat30]

Thanks for the tips!
On last weekend I have carefully examined the engine during idling and tried to give gas to the limit, but there was no any sounds that indicate that the engine have any problems. I also smeared alternators bearings and other moving parts with WD40.

Water pump etc also it seems normal. I did not hear any unusual sounds.

Unfortunately, I have not driven on more than 80 kilometers per hour last week, so I did not have the possibility to check whether if its helped.

A great idea to try to raise the front of the car! I need to buy a pair of jack stand and try to do it.

Metalguru3, thanks for the offer, but I live in Slovenia. Unless of course you accidentally find yourself in this part of the world, then you are welcome to look at my car.

 

[Ralf S.]

Another tip.. if you are driving downhill, put the clutch in and see if the noise remains.

If you still hear the noise then it's probably not related to the alternator, drive belts, water pump etc. since they will be moving at "idle" speed. It has to be something that is still moving at "road speed" (e.g. brakes or drive shafts).

If the sound disappears when you have the clutch in, then the cause is one of these ^^ things, not the brakes or drive shafts.


Ralf S.

 

[MegaVat30]

Hi all.
I think this problem has been fixed.

On the last week the sound began to appear after 10-15 minutes of driving, and already at speed of 50 kilometers per hour it was clearly heard.

As mechanic told me the all 4 front brake pads was shifted and rubbed against the brake disc.

So if you have a similar problem, try to check the brake pads.

Thank you all for your help.