Help to isolate noise - 986 Forum - The Community for Porsche Boxster & Cayman Owners

hookoo3 · 07-09-2011, 03:38 PM

I need help to identify a noise which is getting louder. At first I thought the noise might be tire wear however my fronts are new and the rears were replaced about 5000 km ago. One tire dealer thought it may be cupping noise however the noise is now getting louder with a more metal grinding type of noise. I've had the car up on jack stands and do not hear the noise when engaged in 1st. I do not think it is the bearings as I don't hear any noise when on the jack stands or when driving and holding out my head out the window. I've also now replaced the front motor mount which was worn out and the metal grinding low pitched noise is still there. The noise can be heard in all gears and with the clutch pushed in or out. It does appear to be on a constant rotational basis. The noise seems to come more from the center of the car and is now a metal type of grinding noise on every rotation. Any suggestions on what next to check out is appreciated. Thanks.

2001 Boxster S 6sp 93000km

Jager · 07-09-2011, 07:11 PM

Wheel bearings do wear-out on these cars... Both front and back.

hookoo3 · 07-09-2011, 07:42 PM

Is there a definitive test to figure out which wheel bearings may be going out? Spinning the wheels and listening to each one has not given me any idea if something is wrong. Another thing I have noticed is that it makes the noise only in forward gears, there was no rubbing grinding noise in reverse. And the noise happens on every rotation that is going on. The clutch and shifting seem normal to me. The brake pads are in good condition and on hard stops the car stops fast and smooth with no vibration or pulling. The rear CV boots and bearings were replaced less than 2000km ago. There are no oil leaks on the car. Is there an easy diagnosis for the transmission or differential? Ideas are welcome. Thanks

thstone · 07-09-2011, 10:52 PM

I'd suggest checking the CV joints (check both inner and outer joints).

There is no differential (per se) on a Boxster since the car has a transaxle.

hookoo3 · 07-10-2011, 11:35 AM

thstone, I think you may right. I checked my receipts and I see that all 4 cv boots were replaced and none of the cv joints. The outer boots were quite torn at the time so I now suspect the cv joints are done. Looks like I'll be replacing the complete axle shaft assembly now.

Has anyone actually used the cheap First Equipment Quality parts from China that are almost a tenth of the price of OEM? I know most will not recommend cheap knock-offs but has anyone had any results or reviews using them?

Dale_K · 07-11-2011, 05:04 AM

Auto parts stores sell a special grease for repacking CV joints. It would probably be worth the trouble to peel back one of the boots and see what it looks like inside. If it's really dry you could clean it up and re-grease it. Kind of a low probability repair effort but since it's so cheap (only cost is the grease) it's worth a shot.