Car Parts and Accessories

Where Auto Part Engine heat is lost

The function of the radiator is to dissipate heat from the hot water circulating in the cooling system. It normally consists of a. header or top tank and a bottom or receiving tank, with a core, usually of metal tubes, between them.

Hot water enters the header tank through the thermostat from the water jacket, and flows through the core, where it gives up its heat. The tubes are fitted with fins to provide a greater contact area for the cooling air.

The cooled water passes into the receiving tank and is then returned to the auto part engine through the water pump.

In many radiators a space is left between the surface of the water and the top of the header tank for expansion of water. Any surplus water (or steam) escapes through the overflow to the ground.

In later designs, the overflow is taken to an extra expansion tank away from the radiator. As the water cools, it is drawn hack into the header tank.

This is known as a sealed system. Since no water is allowed to escape, the system is sometimes filled at the factory with a mixture of water and antifreeze. As long as the cooling system remains leakproof, no further attention, other than the occasional inspection, is called for.

Auto Part Engine Antifreeze

In cold weather, freezing water can cause a burst in the radiator of a car which has been left standing. It is equally possible for a radiator to freeze and burst when a car is being driven—even though the water in the auto part engine may be boiling. This is because the thermostat prevents hot water from the auto part engine circulating through the radiator until the auto part engine reaches a set temperature. If a car is driven through cold air, water in the radiator can freeze before the thermostat valve has opened.

Freezing of the radiator can be avoided by adding a chemical – usually glycol or a mixture of glycols and inhibitors.

The SABS has prepared a specification for antifreeze solutions, and motorists should ensure that the antifreeze they buy has the SABS mark, and that it is used according to the instructions on the product. The indiscriminate mixing of different solutions – even from the same manufacturer – should be avoided.

Unless otherwise specified, antifreeze may be left in the cooling system all year round as the inhibitors give protection against corrosion.

Speeding the flow

In most auto part engines, the water pump is mounted on the front of the cylinder block and is driven by the fan belt. It draws cool water from the bottom of the radiator and delivers this into the auto part engine’s water jackets. Water heated by the auto part engine then flows through the cylinder head and the thermostat back into the radiator.

A small flow to the car’s heater, and in some makes to the induction manifold, is returned to the radiator without passing through the thermostat.

The impeller of the pump is a rotating disc carrying vanes, which fling the water outwards against the pump’s casing by centrifugal force and impel it forwards into the water jacket. A seal prevents water from escaping along the impeller shaft.

When the thermostat restricts circulation of the coolant through the radiator, the impeller still revolves, circulating water round the auto part engine only, through the by-pass pipe.

Any squeak from the water-pump seal is usually only temporary. It should not be treated, as some garages advise, by mixing soluble oil (also known as cuttting oil) with the radiator water. Minerals in the soluble oil could rot the rubber hoses in the cooling system.

Air-cooled Auto Part Engines

Air-colling without proper ducting and fan-assisted circulation cannot overcome the difficulty of cooling all cylinders evenly, particularly with in-line auto part engines.

The cylinders at the rear of the auto part engine would get little cooling effect from the flow of air through the grille at the front of the car.

To overcome this, air-cooled auto part engines use a fan to force a cooling airstream over the cylinders. Thermostatic control adjusts the air flow to suit temperature conditions.

Fins on the cylinders and cylinder heads increase the surface exposed to the air. Since certain areas of the cylinders and heads, such as the exhaust ports of the combustion chambers, develop more heat that must be dissipated, the fins are usually bigger in those areas than elsewhere on the auto part engine.

Heat always flows from a large mass of material to the thinnest section exposed to a cooler medium. Fins are therefore tapered, to promote the dissipation of heat.

An air-cooled auto part engine is much noisier than a water-cooled auto part engine, in which the water jacket damps down a great deal of the auto part engine noise.

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