Peace of mind? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

BillyG · 10-30-2010, 10:13 AM

Hi, recently bought a 2002 2.7 and noticed a couple of noises particularly noticeable at idle when warm. First is a low-ish intermittent rumble, more pronouncable when air con is switched on. Second is a slight buzz a bit like exhaust noise (but don't think it is). Can hear particularly well through the right side air intake. Both noises disappear when revs are slightly increased at which point the engine sounds perfect.
Been told by the specialist who sold me it that Boxters often make make a bit of noise and it's nothing to worry about. Also got it checked by my independent mechanic who also seems to think it's fine. Would really appreciate some feedback from you expert owners though. Cheers!

Highlow · 10-30-2010, 10:15 AM

I can't think of the exact noises my car makes when it's idling but I do know that it is much smother, quieter, and happier when the revs are above 2k.

Sounds normal to me, enjoy.

kpm · 10-30-2010, 10:24 AM

The low rumble with the AC on is the compressor, a normal noise. The other sound, I can't say what it might be.

Steve Tinker · 10-30-2010, 06:12 PM

BillyG,
If you are concerned and you're handy with 10mm & 24mm sockets, try removing the polyrib belt that drives the water pump, A/C unit, alternator and power steering and run the engine @ idle.
Only run the engine for a minute max without the belt (no coolant flow) and see if the noise(s) stop. Also give the tensioner/idler pulleys a good wriggle to see if the bearings are OK. My alternator clutch siezed on my car a couple of months ago and the rumbling sound could only be heard at idle.
The Bentlys Boxster service manual is invaluable - I recommend you buy it, even if its just info for regular servicing - it will pay for itself ten fold......

BillyG · 11-01-2010, 11:21 AM

Thanks chaps, very reassuring. Will see if noises get worse before warranty runs out.

BillyG · 11-08-2010, 04:28 AM

Since continuing to drive the car, the sound is becoming moire obvious as a vibration - bit like exhaust noise which appears between idle and about 1K revs. Any further thoughts?

Bruce Wayne · 11-08-2010, 04:35 AM

heat shields ?

how firm is the vibration ?

BillyG · 11-08-2010, 06:04 AM

A kind of buzz is probably the best discription. Wondered whether it may be related to the low rumbly sound which is more noticeable when air con is on.
Don't know if it helps but the only time the noise disappeared recently was after giving the car a bit of a harder drive than I usually would...

Bruce Wayne · 11-08-2010, 06:14 AM

if its more of a tinny buzz it could be a heat shield or baffle, the rumble could well be the extra load on the pulley / belt.

bear in mind jake raby's continual comments to us all about keeping tabs on on the boxster water pump..... if you dont know when it was done, you may well want to consider getting it changed and have the belt pully bearings checked over at the same time.