I have a 1998 Jeep Grand Cherokee that over heats when the A/C is on, should I change the thermostat first?

Answer 1

your problem actually sounds like a radiator problem.
It COULD be the thermostat, however if it only over heating with the A/C on, on a hot day, Then I believe your radiator needs flushed.
Over time the radiator will develop corrosion in the tubes and reduce the cooling capacity. The coolant has corrosion inhibitor in it when new , but, they degrade over time and lose the ability to prevent build up.
1) Check that the radiator and reservoir is full of coolant.
2) If the coolant is not a clear pink or yellow, it needs replaced.
3) if you do it your self , buy a flush kit from the auto parts store and install it in one of the heater hoses. follow the directions on the kit. to flush the engine, you will need to be near a water hose.
4) use the recommended mix of anti-freeze to water...usually 50/50.
5) buy and use some "Water Wetter" it will increase your cooling capacity and mitigate this type of overheating.

You are describing a very common problem with engine overheating this time of year.

6) Check that the fan is working and your belt is in good shape.

7) look at the radiator through the grill, is it plugged with dirt and other road debris? use the high pressure washers at a car wash to clean out the fins, wash out the stuff that gets in there.



Yours: Grumpy

Answer 2

it is worth a try. what is the condition of coolant , 8yr. old truck has it been off road much?you should flush the cooling system out. and then check for debris trapped behind grill blocking condenser and between condenser and radiator these can be flushed away with garden hose or compressed air if you use air wear eye protection as small crap will be flying. almost always you find it is a combination of things that cause an over heat situation

Answer 3

Try and see if there are any part you may want to get checked. I hope it is not your head gasket though.