2002 Volkswagen Passat

Air Conditioning problem
2002 Volkswagen Passat 4 cyl Front Wheel Drive Automatic 90K miles

I have a 2002 VW passat with 90K miles on it.
When I switch on the AC and drive at 30miles/hr speed within 15 to 20 mins the OIL pressure indicator appears.
After 15 to 20 seconds, it dissapears. Then again appears after 3 - 4 mins. If I drive at 50 or above without stopping I never faced this issue. I dont hear any weard noise. Car runs really great. Also when ever I drive with switched ON AC, I see 2 - 3 drop os oil spilled on the parking lot. Is my engine has Oil leak issues?

I have changed the OIL strianer, New Gasket, Water pump and Timming Belt.

Any suggestion will be great since this is driving me crazy.
April 16, 2010.

Try replacing the oil pressure switch and find the leak sooner or later that leak is gonna get bigger and you'll end up with an engine major repair.

Apr 17, 2010.