Asked by Jul 22, 2016 at 05:03 PM about the 2003 Mercury Grand Marquis GS

Question type: Maintenance & Repair

My car overheats when the a/c is on but when i
turn off the a/c is cools back to normal temp

2 Answers


check the cooling fans for proper operation, they should turn on when the A/C is on, also check for dirt and debris in the cooling fins of both the radiator and heat exchanger out front. If the cooling fans work and you can see through the fins then the most likely culprit is the radiator, it is internally plugged and cannot handle more demand made by the A/C.

Bob Beaman

Some of the cooling fans in that era were bad about breaking the ring that holds the blades together. If the cooling fans are making a ticking noise it is time for a new one.

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