Join Date: Nov 2010
Location: United Kingdom
just do a few logical system elimination tests:
1. is it movement related - noise related to speed, various gears related may point to gearbox/transmission
2. is it engine rotational speed related - in neutral is the sound apparent at varying engine speed = engine side of transmission > compressor? anything engine related
3: is it ancillary system dependent : aircon off/on eliminates compressor; air con off and power steering loaded/not loaded may indicate power steering pump issues. Waterpump and drive belt main pulley can be considered as possible culprits but not eliminated by test without removing belt!
Noises are a pig to home in on as there are so many noise paths through the structures, best to look for other clues too.