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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......

10-30-2010, 06:12 PM	#4
Steve Tinker Registered User Join Date: Dec 2008 Location: Queensland, Australia Posts: 1,522	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...... __________________ 2001 Boxster S (triple black). Sleeping easier with LN Engineering/Flat 6 IMS upgrade, low temp thermostat & underspeed pulley. 2001 MV Agusta F4.