I have a 2000 Jeep Grand Cherokee. I had a coolant leak which was determined to be the water pump. I drove the car for a couple months just making sure to add coolant every few days not a bad leak and I had the water pump and thermostat replaced. However the car is now suddenly overheating.
Mostly when stopped, low speeds or any time you turn on the AC. When I tried to check the fan I noticed that the fan comes on as soon as I crank it up. What can cause the car to be overheating and why is the fan staying on? Please help
I would first make sure the radiator is completely full of coolant, which can be a little difficult to see on these vehicles. If you have to add more than a pint of coolant to the system, you probably have a leak somewhere that needs to be repaired. Also make sure there are no air pockets in the system that needs to be bled out.
When the engine is warm, you should not easily be able to squeeze the upper radiator hose together with your bare hands, if you can you have a leak or air in the system. Also the upper and lower radiator hoses should be about the same temperature when the engine is warm. If not, you have a restriction in the radiator, and a new radiator is in order….or you still have air in the system that needs to be bled out.
The fans should cycle on and off at idle speed, although if you have 2 electric fans one is for the a/c and will come on and stay on as the a/c compressor is on. The other fan will be for the radiator and should also cycle on and off as the engine heats up.
Here is a video I made about overheating that might help you narrow things down more.