Select a part to view solution for common problems associated with the item.

Operation: Engine coolant is a 50/50 mixture of antifreeze and water. Besides protecting against freezing, antifreeze also has lubricant and anticorrosive additives that help to prolong the life of the cooling system components. Advice: Any muddiness or brown coloration is an indication of dirt or rust in the system. As antifreeze ages the lubricants and anticorrosive properties wear out, leaving the system susceptible to corrosion. Modern antifreezes have varying life span expectancies. If you are unsure how long your antifreeze is good for, a general rule of thumb is to flush the system and refill with fresh coolant every two years. Some manufacturers recommend a specific type of antifreeze, such as GM's Dex-cool. Check the repair guides for the vehicle that you are working on. Recommendations: Repair guides Antifreeze

Operation: Gasket sealant is used to fill in the small imperfections in the gasket material and the sealing surfaces to be joined. Advice: Before deciding on which type gasket sealant that you need, take a good look at the gaskets that you are replacing. Many gaskets now come with a bead of sealant already applied. If the engine you are working on is computer controlled, make sure that any sealant you buy is safe for oxygen sensors. For paper and fibrous gaskets, a thin coat of sealant on both sides of the gasket is sufficient. Unless otherwise noted, there is no need to use gasket sealant on rubber gaskets. Recommendations: Gasket sealant

Operation: The water pump circulates engine coolant throughout the cooling system. Advice: The main wear point on a water pump is the bearings that support the rotational shaft and the seal that keeps engine coolant from escaping from around the rotational shaft. Most water pumps have a weep hole in the body of the pump directly under the rotational shaft. Check this weep hole for signs of engine coolant seepage. If it is wet or has a dirty white calcium looking buildup coming from around the weep hole, it has been leaking and the water pump should be replaced.

Operation: The thermostat maintains engine operating temperature and regulates the flow of coolant in the engine by opening and closing at predetermined temperatures. Advice: Today's computer controlled engines require specific operating temperature parameters. If the wrong temperature thermostat is installed in a computer controlled engine, the open loop/closed loop parameters can be altered drastically, causing drive-ability problems and poor gas mileage due to prolonged open loop operation. For computer controlled engines always use the same temperature thermostat that originally came with the engine. Some engine designs require that the thermostat be installed with the vent or bypass hole in a certain position. Failure to position the thermostat properly can cause engine overheating. Check the repair guides for the vehicle you are working on. Over time the temperature extremes will effect the integrity of the regulated spring pressure. Whenever the cooling system is opened, it's a good idea to replace the thermostat. Recommendations: Repair guides OEM temperature thermostat Thermostat gasket Gasket sealant Antifreeze

Operation: Air pockets trapped in the cooling system can cause the engine to overheat. Some cooling systems have air bleed valves built into the system to aid in the removal of air pockets. Advice: For many cooling systems, the method of removing air pockets is to start the engine and allow it to run with the radiator cap off or loose until all the air escapes from the neck of the radiator. For some systems this method is not sufficient, and the manufacturer has installed air bleed valves usually near or on the thermostat housing. Consult the repair guides for the vehicle you are working on. Recommendations: Repair guides

Operation: The Radiator routes the hot engine coolant through a network of thin tubes. These tubes are positioned so that the air passing over them cools down the hot engine coolant inside. Engine coolant is stored in the radiator as it cools, then when the thermostat opens hot engine coolant is forced into the radiator and the cooled engine coolant is pushed into the engine. This cycle continues as long as the engine is in operation. Advice: The two main reasons for radiator failure are coolant leakage and internal sludge buildup. Both of these situations can be avoided by changing the engine coolant on a regular basis. Over time the lubricants and other additives in the antifreeze that protect the cooling system from corrosion will wear out. Continuing to use this worn out antifreeze subjects the cooling system to corrosion and scale buildup in the system. The corrosion will cause radiator leaks as well as leaks elsewhere in the system and the scale buildup will cause blockages and will inhibit the radiators ability to disperse the heat efficiently. Recommendations: Change engine coolant at the proper intervals

Operation: The radiator cap is designed to maintain cooling system pressure up to the specification stamped on the top of the cap. For every pound of pressure applied to the coolant, the boiling point is raised about 3.25 degrees F. or 1.8 degrees C. Advice: Check the cap for any signs of corrosion. Check to ensure the physical integrity of the rubber seals. Use a pressure tester to ensure that the pressure relief valve opens at the specified pressure. Recommendations: Radiator cap pressure tester

Operation: Engine coolant expands as it heats up and contracts as it cools down. The radiator cap is designed to allow the hot coolant to expand and build up to a predetermined pressure, then bleed off any pressure beyond that point. This pressure bleed expels a certain amount of engine coolant. The expelled coolant is carried via a tube connected to the neck of the radiator, to the radiator overflow tank. After the engine has been shut down the contraction of the cooling engine coolant creates a vacuum that draws coolant out of the radiator overflow tank back into the engine maintaining a full cooling system with very little maintenance involved. On older vehicles without coolant recovery tanks, the expelled coolant was dumped to the ground. Engine coolant had to be checked and added frequently. Advice: The operation of the coolant recovery system is dependant upon a working radiator cap and a cooling system that is free of leaks. If there is a leak anywhere in the cooling system, it won't be able to create the vacuum necessary to draw coolant out of the coolant recovery tank. You can pressurize the system to check for leaks as well as test the radiator cap with a cooling system pressure tester. Recommendations: Cooling system pressure tester

Operation: Some overflow tanks are incorporated into a sealed and pressurized system. Advice: On these systems, the overflow tank is pressurized when the engine is hot. These systems often will not have a cap on the radiator. Follow the directions on the cap of the overflow tank, serious burns can result from opening the system carelessly.

Operation: The low coolant warning switch is often found built into the radiator overflow tank. It uses a float that closes the contacts on an electrical switch when allowed to drop below a predetermined coolant level. Advice: Use care when disconnecting the wiring harness connector. Over time the under hood temperature extremes can cause the plastic connectors to become brittle and easy to break. A broken connector can lose it's ability to seal out the damaging moisture and dirt. Replace any broken connectors before corrosion sets in.

Operation: The radiator fan motor is responsible for driving the radiator fan whenever necessary. Advice: There could be several reasons for the radiator fan not to be coming on. Before replacing the fan motor try hotwiring it to see if the motor will run. Disconnect the two wire connector at the fan motor and run two jumper wires from the battery. If you get the polarity backwards the fan will still run, just backwards but it will answer the question of whether or not the motor is bad. If the motor runs on the hotwire setup, it's good and the problem lies somewhere else.

Operation: The cooling fan is designed to draw air over the cooling fins of the radiator. Advice: A faulty fan blade can be very dangerous! While the fan is off is a good time to closely inspect it for stress cracks, or bent or loose blades.

Advice: Belts and hoses are usually not thought about until they break or start leaking. Periodic inspection and replacement of the belts and hoses can help to avoid one of those side of the road experiences.

Operation: Hose clamps apply a squeezing force to the end of the hose in an effort to seal the hose to the pipe or junction that it is attached to. Advice: If the clamps are the screw type, check to make sure that the threads are in good shape and not distorted or stripped from prior over tightening. If the clamps are the spring tension type, you may want to consider replacing them with the screw type. Over time and countless hot/cold cycles the tension on a spring type clamp can change. Recommendations: Hose clamps

Operation: Idler pulleys are used for belt routing and help to maintain belt alignment. Advice: Idler pulley bearings are of the sealed type and can not be serviced. Check to make sure that there is no wobble or play in the bearing and that it turns smoothly. If any play or roughness is found, the Idler pulley should be replaced. If spring tension is being used, ensure the integrity of the spring. Recommendations: Idler pulley

Operation: A tensioner pulley is used to maintain proper belt tension. Some belt tensioners are locked in place with a bolt or nut after correct adjustment has been made. Other designs use spring tension to automatically tension the belt. Advice: Too much tension will cause a strain on any bearings involved. Not enough tension can lead to slippage or belts jumping off. Tensioner pulley bearings are of the sealed type and can not be serviced. Check to make sure that there is no wobble or play in the bearing and that it turns smoothly. If any play or roughness is found, the tensioner pulley should be replaced. If spring tension is being used, ensure the integrity of the spring. Recommendations: Belt tensioner Tensioner pulley