Hi everybody i posted this question a while back and have found the answer, i hope this prooves helpful to someone.
This post concerns an engine whstle at idle, my Legacy 93' EJ 22 non turbo engine was making.
The sound is a single high pitched sound more noticeable when engine under load and Air Conditioning on
The sound is noticeable from 800 rpm to 1300 rpm and when iake my foot off the gas it dissappears untill the rpm drops to 850 rpm (minimum idle).
The high pitched sound is more noticeable when the engine is warm.
The timing belt has been recently changed and the belts seem in good condition also power streering, alternator and air conditioning belts are all ok, when i remove these belts the noise is still there, if i remove the timing belt left and right side covers the noise does not change (get louder).
It dose not sound like a wwwrrr sound
The answer is the sound was coming from a clogged throttle body, running an upper cylinder clean cured the problem.