It's the middle of summer, your perspiration drips like a river and your car's interior is like the furnaces of hell. Your car overheats, stalling in the middle of the road.
You have a problem with your cooling system, mate.
Your car's cooling system should remove the excess heat from your car's engines, keeping the engine operating on the most efficient temperature settings, and allowing the engine to reach its ideal operating temperature at the shortest time possible.
In its ideal sense, the cooling system should keep the engine running at its most efficient temperature even at the most punishing operating conditions thrown at it.
As fuel is burned, energy is released. If there is no cooling system, the heat from the fuel would melt the parts, and the pistons would expand so much that they would not move inside the cylinders.
The cooling system of a water-cooled engine consists of:
the engine's water jacket
thermostat
water pump
radiator and radiator cap
cooling fan (electric or belt-driven)
hoses
heater core
expansion (overflow) tank
Burning the fuel produces a large amount of heat; temperatures can reach up to 4,000 degrees Fahrenheit if the right fuel/air ratio is reached. The cooling system removes as much as 1/3 of the heat generated by the fuel combustion.
You car's engines are cooled by liquid circulating inside tubes lined inside the engine compartment. Liquid 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 cooling system problems:
1. Broken tubing. Hoses and tubing wear out and leak coolant fluid. Once the coolant has left the system it can no longer cool the engine and therefore the engine will over heat.
2. Broken fan belt. The water pump is driven by the engine through a fan belt. If this belt breaks the water pump can not turn and coolant will not be pushed through the car engine. This will also lead to the engine overheating.
3. Damaged radiator cap. The radiator cap is designed to hold a certain pressure in the coolant system. Most caps hold 8 - 12 PSI. This pressure raises the point in which the coolant will boil and maintains a good, stable system. If your cap does not hold enough pressure, then the car engine could overheat on hot days since the system never becomes pressurized.
4. Water pumps failure. Most commonly you will hear a horrible screeching noise and will be able to see engine coolant leaking from the front of the pump or underneath the car. Often there are early signs of trouble with small spots of coolant under the car after being parked overnight and a strong coolant odor whilst you are driving.
5. Head gasket... Do you have large amounts of white smoke flowing out of your exhaust? Then you could have a problem with your head gasket. The head gasket seals the cylinder head to the engine block and also seals the coolant passages. When this gasket fails coolant can enter the cylinder and it will be turned to vapor as the engine fires. Head gaskets most often fail after the engine has overheated in the past. When very hot, the cylinder head can warp and prevent the engine head gasket from sealing properly.
Preventive Maintenance on Engine Cooling Systems
1. Check all belts and hoses regularly. (At oil change is a good time)
2. Look out for coolant leaks underneath the car; they could be signs of trouble to come.
3. Change your coolant every 2 - 3 years depending on the manufacturer's recommendations.
4. Inspect your radiator cap for deterioration of the rubber seal. Replace if you think it is worn. $5 - $10 is cheap insurance.
5. Have your coolant system flushed every 5 years. It gets all the corrosion which has built up out of the system.
