Learn how your cooling system works to find problems in a faulty system. Briefly speaking, coolant picks up heat when going through the engine and releases it when passing in the radiator. Your cooling system‘s role includes circulating coolant, containing it or controlling its temperature. Troubleshoot the cooling system in a Jeep Grand Cherokee by checking cooling system devices. Use these steps with most model years.
1. Inspect the water pump for leakage. Your water pump circulates coolant through the radiator, heater core and engine. A slight antifreeze smell or spots of coolant under your Grand Cherokee when parked for a short duration are signs of a damaged water pump.
2. Check hoses for cracks, collapses, leaks or dry appearance. When checking, look at upper and lower radiator hoses, heater and bypass hoses and manifold coolant hoses. The upper hoses measure some 2 inches wide and transport coolant between the radiator and engine. Cooling system problems could stem from damaged hoses.
3. Examine your coolant level. Low antifreeze can cause overheating. With low levels, add antifreeze to the coolant tank reservoir. Use Mopar Antifreeze/Coolant 5 year, 100,000 Mile Formula HOAT (Hybrid Organic Additive Technology) and low mineral content water. This applies to the V6 and V8 engines.
4. Drain the coolant and flush the system when diagnosing problems.
5. Look at your radiator cap for signs of damage. For example, a worn out cap could contain corrosion. Find a mechanic with a pressure tester or an adapter to test the cap’s pressure rating and operation. Quickly replace a defective cap.
6. Wash and rinse the front of your radiator. Dirt, rocks, leaves and other debris pull into the radiator fins when you drive which results in overheating. Get a soft nylon brush, soapy water and a yard hose to clean your radiator front.
7. See if the thermostat is stuck. One way to identify a sticking thermostat is constant low temperature readings or peaks between high and normal temperatures. Usually, the thermostat, the spring-loaded valve that reacts to coolant temperatures, sits inside the housing on the engine side of the upper radiator hose.