Sorry if this is not specific enough for valid advice, but in the past 3 days my 2004 996 C4 has been making a whining noise from the rear.
It seems engine speed related but is not so audible at idle. Peaks at around 1000-1500 RPM then gets higher pitched until road noise suppresses it.
At its peak it sounds a bit like a circular saw! Tends to subside when the engine gets hot, but today it only quietened after about 18 miles.
It's not the A/C pump- happens regardless of A/C being on/off, and it has been recently regassed.
Happens whether in gear or coasting in neutral.
Could this be from the alternator, or water pump?
It seems engine speed related but is not so audible at idle. Peaks at around 1000-1500 RPM then gets higher pitched until road noise suppresses it.
At its peak it sounds a bit like a circular saw! Tends to subside when the engine gets hot, but today it only quietened after about 18 miles.
It's not the A/C pump- happens regardless of A/C being on/off, and it has been recently regassed.
Happens whether in gear or coasting in neutral.
Could this be from the alternator, or water pump?