I have a problem with my cooling sytem. Here are the facts:

Freeway (60-100kph):
- temp at 80 degress or lower (GREAT TEMP)!

Heavy Traffic:
- temp at 100-110 degress
- I have to rev. (1500 rpm or higher) the engine during stops to prevent the temp. going up to 120 degrees
- when I rev. the engine the lowest it would go is about 100-105 degrees, but once the card start to move and maintain a constant speed of about 80kph it goes down to 80 degress or below.
- My OIL PRESSURE also drops to like 1 during idling when I hit 110 degrees.

QUESTIONS:

- Am I using the right OIL?
- Is there a relation of the cooling system when the engine is REVING high and ON THE FREEWAY? The only difference that is obvious is that when I'm on the freeway there is AIR coming through. - Is it possible that my radiator's fins or AC fins are just dirty?
- Could the CLUTCH FAN be busted?


Would appreciate the comments.


Thanks!

Francis