Hi,

 

My car has recently developed usual high pitch clicking noise from engine when accelerating. This only happens when heater/air con fan is on. 

I suspect it's related to the air con system, as i recently noticed oil leaks from air con connecting pipes.

 

Could this be sign that my compressor is failing or faulty?

 

I appreciate it's hard to diagnosis without listening to it. Thanks.

Sure it's not pinking?

Won't it be pinking all the time. i test drove for few days without using the heater/fan and sounded fine. starts as soon as fan/heater is on.

 

Have you checked there is nothing stuck in the fan? Leaves or the suchlike.

Drop the cabin filter from inside the passenger footwell and pop your hand in and feel around. Run the fan a bit with filter out so any loose debris can fall out. Keep fingers clear of spinning fan though as that will smart!