Chuck,


Sure, the higher temperature air coming from the AC condenser causes the engine to run hotter if the tubes of the radiator are coated on the inside with crud. This crud decreases the heat transfer from the water to the tubes thus the water remains hotter than it would in a radiator with clean tubes.

If the buildup in the tubes gets thick enough, it restricts the waterflow in the radiator. That's why radiators are flow tested.

P E H