MY car overheats every summer when I use the A/C. I have took it in for various services and no one can figure out what's wrong. This started happening after I got some flushes done a couple years ago. Ever since then when its over 90 degrees the engine gets really loud and I have to turn off the A/C and suffer.
Overheating on 2003 Ford Expedition
by Alexandra in Fontana, CA on July 20, 2009
ANSWER by patrick mannion , July 20, 2009
Air conditioning does put an extra load on the engine. I wonder if the radiator itself is a little restricted internally or if you should put a slightly cooler thermostat in the engine. I will send you an article I wrote about testing the cooling system. The radiator efficiency and "block check" paragraphs may be relevant to your running hot issue.