Thrumming Noise When Driving - What Is It?

[Guest philjw]

Hi,

My C5 has developed a thrumming noise which sounds like it's running on square wheels. The noise appears to come from the N/S front. It becomes noticeable at around 35 mph and gets worse with speed. It's worse when cornering. The car has now done 103 K. I've changed the front discs and pads and recently cleaned the corrosion from the rear.

I can't find any play in either drop link or front wheel bearings.

Front tyres are on the way out with about 3mm tread but no obvious faults. Tried the spare on the N/S front with no change in the noise.

What do you all think may be causing the noise? Wheel bearings? I'm getting fed up with it!

 

Phil

05 C5 Estate 2.0 16v + 05 C4 Hatchback 2.0 16V

[Randombloke]

Jack up the car and look for a blister starting to form on the tread of your front tyres.

[Guest philjw]

Thanks for the response but there's nothing obviously wrong with the tyres.

Phil

[Johndouglas]

It becomes noticeable at around 35 mph and gets worse with speed. It's worse when cornering.

 

My guess would be a wheel bearing rumbling. It might not be apparent when spinning the wheel. At least not yet.

[coastline taxis]

Check your inner drivshaft joint and the gearbox oil level

[Randombloke]

Thanks for the response but there's nothing obviously wrong with the tyres.

Phil

 

No balance weights gone missing?

 

Otherwise, I'm afraid that Coastline's suggestion looks very likely.

[Guest C5buff]

Hi

Did the noise start after the brakes were done, or was it there before?

[Guest philjw]

The noise started before doing the brakes. The discs were on the limit of thickness so I changed them partly in case they were out of true and causing the noise.

Coastline says check the drive shaft joint. What's the best way of doing this? I've tried grabbing the shaft and trying to move it up & down - nothing noticeable and turning the hub back & forth - some movement before the slack is taken up.

As for balance weights the car has alloys (exclusive model)and still has some stuck on balance weights on the suspect wheel so I reckon they are all still there. Also swapping the wheel for the spare made no difference

I'll try the oil level. Do you think the oil should be changed anyway? The car has always had main dealer servicing but I don't think changing the gear oil is in the service schedule as Citroen say it's good for the life of the vehicle so it may not have been done.

Phil

[Guest C5buff]

Hi

To try and get a better fix on the problem. (Not sure if this will work) jack up the car on axel stands at the front and firmly chock rear wheels.

Get somebody else to start the engine and engage gears and drive it, with you on the outside looking and listening for the noises. Turning the wheels from left to right and at the same time applying the hand brake or footbrake so as to load the drive train. This may provoke the trouble in a way that will give you a clue to what it is.

Needless to say, be careful and dont get yourself in contact with the spinning wheels.

[Guest philjw]

Hi

To try and get a better fix on the problem. (Not sure if this will work) jack up the car on axel stands at the front and firmly chock rear wheels.

Get somebody else to start the engine and engage gears and drive it, with you on the outside looking and listening for the noises. Turning the wheels from left to right and at the same time applying the hand brake or footbrake so as to load the drive train. This may provoke the trouble in a way that will give you a clue to what it is.

Needless to say, be careful and dont get yourself in contact with the spinning wheels.

 

I tried this on my own and with the car in gear but with no load there was no noise apparrent. Well apart from my silent scream when I realised that the doors had locked themselves as the car thought it was going more than the 6 mph it takes for the auto locking feature to kick in! Thank goodness for the spare key. I'm a bit wary of trying again.

Phil

[coastline taxis]

sealed for life is yours a automatic

[Guest philjw]

sealed for life is yours a automatic

No it's got the 6 speed manual box

[Guest C5buff]

Well its a rotational noise so that means drive joints, wheel bearings, gearbox. OR maybe brake pads that have a missing or missaligned or damaged anti chatter spring.

The rotational test with the brakes on loading the drive train as my previous post suggested should perhaps be tried again. It must show up with that I would think.

[paul.h]

When I have had worn wheel bearings the noise has sounded similar to an aeroplane and got louder as the speed was increased and louder when turning. Deciding which wheel is not easy, it may seem to be from one wheel but has not always been that one and could also be from a rear. With the car jacked up, if you can detect play by waggling the wheel, repeat with the brakes applied and if a wheel bearing then the play should be gone but if play in the suspension then it will remain (got this from Car Mechanics). Rotating/spinning the wheel by hand may show some roughness but with brake pads installed/driven wheels this may mask anything. After a run the wheel may feel warmer than the others. I have also had noises from badly worn tyres where the tread blocks have feathered which could be felt by running a hand over the treads and seen.

 

I can imagine C5buff's test is exciting, but in use there may be about ½ tonne load on each wheel which would be difficult to achieve when on axle stands. Brake test rollers at an MOT station may work.

[Guest C5buff]

Hi

Paul is correct about the weight on the wheel bearings, but drive joints and gearbox don't feel weight they feel rotational drag due to wieght which is simulated in this case by putting on the brakes as per my suggestion. If there is a problem in the drive train it may then show up. If nothing shows then it would indicate that the wheel bearing is now suspect, since the drive train has been eliminated. Its my best guess on how to diagnose the problem, avoiding having to pay a garage to do it.