Tech Tip - April 2011

Carter Automotive
107 West 11th Street
Coffeyville, KS 67337
Phone: (800) 225-4813 (620) 251-4700
FAX: (620) 251-2215

Understanding and Maintaining Your Vehicle's Cooling System

The purpose of your cooling system is to provide a constant stable operating temperature for the engine under all conditions of use. A water pump pushes hot coolant from the engine block and circulates it through the heater core (to heat the passenger compartment when needed) and through the radiator to dissipate the heat to the air passing through the radiator. The coolant temperature is kept constant by an inline thermostat that regulates how much coolant the pump can circulate.

Keeping your cooling system properly maintained is vital to your vehicle's performance and fuel efficiency. A poorly maintained coolant system will eventually cause rough running and dangerous overheating which can completely ruin today's modern engines.

Cooling System Components.

Radiator: The role of the radiator is dual fold: storing coolant until it's needed and allowing air to pass through it to cool the hot coolant thus removing heat generated by the engine. Today's radiators are often a mixture of metal and plastic components. The cooling fins are often made of aluminum which is a good heat conductor and the outside housing is often made of plastic to save weight and cost. The radiator cap must fit snugly and securely to keep hot coolant steam from escaping into the air but must vent at the correct pressure to allow hot coolant to escape in an overheating scenario without damaging more expense parts such as the radiator itself or the hoses. The overflow bottle acts as a storage vessle to allow hot, expanded coolant to overflow the radiator and then be sucked backed in again once the coolant condenses as it cools.

Water Pump: The water pump sends coolant from the engine block through the coolant hoses to various parts of the cooling system.. In most vehicles on the road today, the water pump is mechanical and is usually installed in the front of the engine block near the radiator. The pump is driven by a belt on the front of the engine and is lubricated by the coolant itself which often contains lubricant and anti-corrosion additive packs specific to the engine's design.

Belts and Hoses: The drive belt for the water pump is usually either a serpentine belt that operates all the various accesories under the hood or it has a dedicated belt that operates only the water pump (mostly older designs). Either way, if the belt fails, the engine will rapidly become too hot to operate and may be damaged. Replace your belt at the first sign of cracking, wear, squeeling or carry a spare. The hoses carry coolant to various parts of the engine (intake manifold), to and from heater core, to and from radiator, etc. A failure of any hose will quickly allow all coolant to escape shutting you down. Regularly inspect (visually and by squeezing) the hoses to check for dry rot, cracking, and stiffness. A cool hose in good condition should be soft, supple and smooth. Replace if needed or carry spares.

Thermostat: This device keeps the coolant at a constant temperature. When coolant reaches designed engine operating temperature, thermostat's internal gate opens and allows coolant to flow back into the engine block cooling it. Most modern fuel injected vehicle's fuel ratio maps are calibrated to work at the thermostat's design temperature. An incorrect or faulty thermostat can cause damage to catalytic converters (car running too rich) and oxygen sensors as well as cause fuel economy to suffer.

Radiator Cap: The radiator cap has a pressure release valve that allows pressure to vent at a preset value. If overheating occurs, the pressure developed will vent through the cap saving more expensive and difficult to replace components from rupturing. However, at normal operating temperatures, the cap does not allow any coolant to escape to the atmosphere so it is not necessary to constant top off the fluid and the system remains sealed.

Coolant: Coolant is most often a mix of distilled water and ethylene or propylene glycol along with additives to improve lubrication and inhibit corrosion. For optimum engine performance and a healthy coolant system, when flusing or replacing your coolant always choose a respected brand of quality antifreeze (per owner's manual), and be sure to either select a pre-diluted product or use de-ionized or distlled water to dilute it to the correct ratio for your winter climate. The degrees of freezing protection are listed on each bottle of antifreeze for common dilution ratios. Mineral free water is essential for keeping hard water deposits from forming inside your radiator and eventually blocking small passages. It can also interfere with the anti-corrosion additives and set up small galvanic currents between dissimilar metals inside the cooling system which will eventually cause a failure.

Keeping Your Cooling System Maintained

Most manufactures specify a coolant flush interval. At this interval, the old coolant is to be drained and replaced with fresh coolant. This keeps additive packs fresh so seals and water pump bearings last as long as possible and also refreshes the anti-corrosion additives to keep the inside of the cooling system clean and smooth for efficient heat transfer.

You can do a lot to make sure your car is reliable and cooling system is clean and safe. For help, talk to a friendly Carter Automotive representative who will answer your questions and get you the quality parts you need.

Print me and take me to one of the 5 Carter Automotive locations in SE Kansas. Our friendly and knowledgeable counter staff will help you find the perfect parts for your application at the right price.