The Cooling System

Written by Kevin Schappell

The purpose ofrepparttar engine's cooling system is to remove excess heat fromrepparttar 102747 engine, to keeprepparttar 102748 engine operating at its most efficient temperature, and to getrepparttar 102749 engine up torepparttar 102750 correct temperature as soon as possible after starting. Ideally,repparttar 102751 cooling system keepsrepparttar 102752 engine running at its most efficient temperature no matter whatrepparttar 102753 operating conditions are. As fuel is burned inrepparttar 102754 engine, about one-third ofrepparttar 102755 energy inrepparttar 102756 fuel is converted into power. Another third goes outrepparttar 102757 exhaust pipe unused, andrepparttar 102758 remaining third becomes heat energy. A cooling system of some kind is necessary in any internal combustion engine. If no cooling system were provided, parts would melt fromrepparttar 102759 heat ofrepparttar 102760 burning fuel, andrepparttar 102761 pistons would expand so much they could not move inrepparttar 102762 cylinders (called "seize"). The cooling system of a water-cooled engine consists of:repparttar 102763 engine's water jacket, a thermostat, a water pump, a radiator and radiator cap, a cooling fan (electric or belt-driven), hoses,repparttar 102764 heater core, and usually an expansion (overflow) tank. Fuel burning engines produce enormous amounts of heat; temperatures can reach up to 4,000 degrees F whenrepparttar 102765 air-fuel mixture burns. However, normal operating temperature is about 2,000 degrees F. The cooling system removes about one-third ofrepparttar 102766 heat produced inrepparttar 102767 combustion chamber. The exhaust system takes away much ofrepparttar 102768 heat, but parts ofrepparttar 102769 engine, such asrepparttar 102770 cylinder walls, pistons, and cylinder head, absorb large amounts ofrepparttar 102771 heat. If a part ofrepparttar 102772 engine gets too hot,repparttar 102773 oil film fails to protect it. This lack of lubrication can ruinrepparttar 102774 engine. Onrepparttar 102775 other hand, if an engine runs at too low a temperature, it is inefficient,repparttar 102776 oil gets dirty (adding wear and subtracting horsepower), deposits form, and fuel mileage is poor-- not to mention exhaust emissions! For these reasons,repparttar 102777 cooling system is designed to stay out ofrepparttar 102778 action untilrepparttar 102779 engine is warmed up. There are two types of cooling systems; liquid cooling and air cooling. Most auto engines are cooled byrepparttar 102780 liquid type; air cooling is used more frequently for airplanes, motorcycles and lawnmowers. Liquid cooled engines have passages forrepparttar 102781 liquid, or coolant, throughrepparttar 102782 cylinder block and head. The coolant has to have indirect contact with such engine parts asrepparttar 102783 combustion chamber,repparttar 102784 cylinder walls, andrepparttar 102785 valve seats and guides. Running throughrepparttar 102786 passages inrepparttar 102787 engine heatsrepparttar 102788 coolant (it absorbsrepparttar 102789 heat fromrepparttar 102790 engine parts), and going throughrepparttar 102791 radiator cools it. After getting "cool" again inrepparttar 102792 radiator,repparttar 102793 coolant comes back throughrepparttar 102794 engine. This business continues as long asrepparttar 102795 engine is running, withrepparttar 102796 coolant absorbing and removingrepparttar 102797 engine's heat, andrepparttar 102798 radiator coolingrepparttar 102799 coolant. A cooling system pressure tester is used to checkrepparttar 102800 pressure inrepparttar 102801 cooling system, which allowsrepparttar 102802 mechanic to determine ifrepparttar 102803 system has any slow leaks. The leak can then be found and fixed before it causes a major problem.

Oil / Lubricants

Written by Kevin Schappell

I receive a lot of questions regarding oil andrepparttar least understood part isrepparttar 102746 number system used to rate oils. Oil weight, or viscosity, refers to how thick or thinrepparttar 102747 oil is. The temperature requirements set for oil, byrepparttar 102748 Society of Automotive Engineers (SAE) is 0 degrees F (low) and 210 degrees F (high). Oils meetingrepparttar 102749 SAE's low temperature requirements have a "W" afterrepparttar 102750 viscosity rating (example: 10W), and oils that meetrepparttar 102751 high ratings have no letter (example SAE 30). Oil is rated for viscosity by heating it to a specified temperature, and then allowing it to flow out of a specifically sized hole. Its viscosity rating is determined byrepparttar 102752 length of time it takes to flow out ofrepparttar 102753 hole. If it flows quickly, it gets a low rating. If it flows slowly, it gets a high rating.

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