Have a tick that only happens once the A/C is turned on. It gets louder as the RPM's increase. Once you turn off the compressor it stops. I am assuming the compressor has a bad vane and is in need of replacement. Any suggestions as to where I can get a new part. I know its not a Lotus part and figure it can be purchased from a local supply house for less than a Lotus dealer...Any idea of the freon type used on the 2002 cars???