How to Troubleshoot the Cooling System in a Nissan Pathfinder

Deal with cooling system problems by knowing how the system works. In simple terms, coolant picks up heat when it goes through the engine and releases heat in the radiator. Cooling devices work by circulating antifreeze, containing it or controlling its temperature. Troubleshoot the cooling system in a Nissan Pathfinder by regularly inspecting cooling system devices. The following steps apply for most model years.

Instructions

1. Find out if your water pump is leaking. The water pump pushes coolant through the engine, radiator and heater core. A slight smell of antifreeze or spots of it under your Pathfinder when parked for a short time mean your water pump is faulty.

2. See if your hoses contain cracks, collapses, leaks or dryness. This goes for upper and lower radiator hoses, heater and bypass hoses and manifold coolant hoses. Your upper hoses measure about 2 inches wide and transport coolant between the radiator and engine. Damaged hoses lead to cooling system problems.

3. Look over the antifreeze level. Overheating can result from low coolant amounts, so add antifreeze to the coolant tank reservoir. Put a 50/50 mixture of an ethylene glycol coolant and soft water in your reservoir. This goes for the VG33E engine.

4. Drain and flush the cooling system when troubleshooting problems. Use caution with the brightly colored sweet-smelling antifreeze. It attracts animals and small children, so dispose of antifreeze properly. Ingesting coolant can be fatal.

5. Inspect the radiator cap for signs of wear and tear. For example, a damaged cap can erode. Consider getting a mechanic to use a pressure tester or an adapter to inspect the cap's pressure rating and operation. Replace a defective cap right away.

6. Wash and softly scrub the front of your radiator. Dirt, rocks, leaves and other debris suck into the vents of your radiator when you drive. This causes overheating. Clean the radiator front with soapy water and a soft nylon brush. Use a garden hose to rinse it.

7. Test the thermostat for sticking. A couple of ways to pinpoint a stuck thermostat are constant low temperature readings or peaks between high and normal temperatures. Your thermostat usually resides in the housing on the engine side of the upper radiator hose.