Humming Noise

[caister]

This is a weird one.

My cars developed a very quiet humming noise over the last few days. It seems to be most noticable at 80mph and around 40.

If I depress the clutch so the engine is idling whilst travelling at these speeds the noise persists so I know its not engine related. However it doesn't get louder whilst cornering or with an increase in speed like I would expect from a wheel bearing.

Any idea what would be causing it? Its not very loud at all but i'm just trying to work out what it is incase its something that needs addressing.

 

[richy22]

Clutch bearing??

 

[Dave..]

CV Boot? Mines leaked all it's grease, and I'm convinced that's what's been making a quiet droning noise.

 

[caister]

CV Boot? Mines leaked all it's grease, and I'm convinced that's what's been making a quiet droning noise.

My CV boot did come off a few months ago but it still had most of its grease in there and its been repacked. Its definately one of my options though I can't hear it making any noise's when doing sharp turns.

Whats the best way of checking the CV joint?

I'm starting to think its possibly the rear bearings again. Though i only did them 25,000 miles ago. Ive had the car up on stands this evening and there doesn't seem to be any play in them but they can't be ruled out.

 

[Rossy197]

Most prob the wheel bearings.. Though they would normally wine at all speeds..

Thrust bearing on the clutch is a possiblitly

 

[Mike@Rentech]

Front wheel bearing or gearbox bearings IMO.

 

[caister]

gearbox one sounds expensive!!!

Would the gearbox still whine at speed if the clutch was disengaged and I was running in neutral?

 

[caister]

anyone? I want to try and get this diagnosed so I can go buy the neccessary parts! A list of things to try would be ideal.

Cheers

 

[Mike@Rentech]

gearbox one sounds expensive!!!

Would the gearbox still whine at speed if the clutch was disengaged and I was running in neutral?

yes

 

[caister]

Could be that then.

I noticed last night that one of my rear disk bearings has leaked all of its grease out of the ruber seal so i'm inclined to think its that thats knackered. The whining has become more noticable at other speeds as well now and increases on left hand turns which to me is pointing towards a bearing. I'm 80% sure its coming from the rear and it just tallys up with the grease coming out of the bearing.

Sound like a good diagnosis?

 

[Greeny.]

Is this gearbox bearing the trust release bearing? Mine makes a noise when the clutch isnt engauged but there isnt a point in changing it until the clutch goes, I belive its part of the kit.

Edit: sounds like a wheel bearing now lol

 

[caister]

A damaged thrust bearing as far as i'm aware will makes a noise in neutral with the clutch engaged but the noise will stop when the clutch is depressed.

 

[LeCar]

Clutch bearing??

think a clutch bearing noise disappears when you depress it?!

 

[caister]

Thanks for the help everybody.

Just to confirm it was the rear bearings. They were totally knackered. Probably my fault for doing them up FT instead of using a torque wrench.

 

[bearne1]

Owned a 172 and now a Trophy and now think I have same problem as I had before - rear bearing whine / hum. Are these made of paper or just have an incredibly small life?!

 

[The_Pirate]

imo itll be a rear wheel bearing

 

[bearne1]

Any idea on the life of a set of OEM rear bearings?

 

[Dave..]

CV Boot? Mines leaked all it's grease, and I'm convinced that's what's been making a quiet droning noise.

Wrong! It'll be the rear wheel bearing. Makes much more noise with the rear seats out.

 

[DannoTheGreat]

as said, rear bearing.

 

[caister]

Any idea on the life of a set of OEM rear bearings?

Depends how you drive and on track use etc so its hard to put a figure on it.