964 C2 Thrumming noise at 40-50 mph

[Simon JH]

Hi,
Wonder if anyone has any experience of this? Noise occurs in gear or coasting and I am wondering if it is perhaps a wheel bearing?

 

[Dekker]

If you jack the car and turn each wheel listening for a noise.
Remove the wheels and use a stethoscope or something solid like a large long screwdriver. Put the sharp end to the hub area pressing ear to the handle and again turn the wheel hub to identify the bearing.

 

[Simon JH]

Thanks - will have a go.

 

[Motorhead]

If not a wheel bearing Simon, it's quite possible that it's a tyre.

Check your tyre wear profiles, particularly if your tyres are old, even if there's plenty of tread left. Look for a sawtooth edge, but even if there's no obvious evidence it's still possible that the heterodyning is being caused by the tyre.

Try swapping wheels with your spare to identify the problematic tyre.

Jeff

 

[vitesse]

When we had our 964 C2,eventually the "thrumming " noise was traced to the offside rear wheel bearing although I have to say the rear tyres tended to be noisy until I changed to new Kumho's( is that the spelling?).
Sadly,I still have that bearing & you are hard pressed to detect wear in it,but the new one cured the problem-I half expected a well worn Thrum to drop out of it in fact -we find a lot of those around here particularly on the coast road.

Also one gets a lot of heterodynes on the beach [] but rarer still are Superaheteradynes mainly restricted to my garage wireless,so easily eliminated.[]

 

[pse_SC]

Also one gets a lot of heterodynes on the beach [] but rarer still are Superaheteradynes mainly restricted to my garage wireless,so easily eliminated.[]

Know what you mean. Can’t keep a good Superheteradyne down (or quiet for that matter)...