| How Your Car Engine Keeps Cool |
|
The function of the engine's cooling system is to remove excess heat from the engine, to keep the engine operating at the most efficient temperature, and to allow the engine to reach its ideal operation temperature in the shortest time possible. In an ideal world, the cooling system keeps the engine running at its most efficient temperature no matter what the operating conditions are.
As petrol is burned in the engine, about one-third of the energy in the fuel is converted into power. Another third goes out the exhaust pipe unused, and the 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 from the heat of the burning petrol, and the pistons would expand so much they could not move in the cylinders (called "seize"). The cooling system of a water-cooled engine consists of:
Burning of fuel in an engines produce very large amounts of heat and pressure; temperatures can reach up to 4,000 degrees F in the engine when the air/petrol mix is in certain proportions correctly. Under normal operating conditions the temperature is about 2,000 degrees F. The cooling system removes around 1/3 of all the heat that is produced in the engine combustion chamber. The exhaust system also takes away much of the heat, but parts of the engine, such as the cylinder walls, pistons, and cylinder head, absorb large amounts of the heat. If a part of the engine gets too hot, the oil film will burn away and thus fail to protect it. This lack of lubrication can quickly destroy a car engine. On the other side, if an engine runs at too low a temperature, it loses efficiency, the oil starts to get dirty (adding wear and reducing power output), deposits form, and fuel mileage is poor-- not to mention poor exhaust emissions! For these reasons, the cooling system only comes into action when the engine has heated up to its optimal temperature. Type of Car Engine Cooling SystemThere are two types of cooling systems; liquid cooling and air cooling. Most auto engines are cooled by the liquid type; air cooling is used more frequently for airplanes, motorcycles and lawnmowers. Liquid Cooled EnginesLiquid cooled engines have passages for the liquid, or coolant, through the cylinder block and head. The coolant has to have indirect contact with such engine parts as the combustion chamber, the cylinder walls, and the valve seats and guides. Running through the passages in the engine heats the coolant (it absorbs the heat from the engine parts), and going through the radiator cools it. After getting "cool" again in the radiator, the coolant comes back through the engine. This business continues as long as the engine is running, with the coolant absorbing and removing the engine's heat, and the radiator cooling the coolant.A cooling system pressure tester is used to check the pressure in the cooling system, which allows the mechanic to determine if the system has any slow leaks. The leak can then be found and fixed before it causes a major problem. Common Engine Cooling Problems:Let's look at the common problems cars have with the cooling system.
Preventive Maintenance on Engine Cooling Systems
What to discuss with your car mechanic:Let your mechanic know when your overheating problems occur. Overheating when idling points to a different problem than overheating at highway speeds.Ask your mechanic if it's worth changing the timing belt or chain while he is replacing your water pump. Many times the timing belt turns the water pump so it has to be removed anyway to access the water pump. WARNING: Never open your engine radiator when the engine is hot. The pressure in the cooling system can cause hot coolant to splash out and burn you. Tag MainSpot.NET In:          |