Volkswagen Golf/Jetta 2 manual

General information and precautions
Cooling, heating and air conditioning systems / General information and precautions


General information
Cooling and heating systems The cooling system is of pressurised type and includes a front mounted radiator, coolant pump, expansion tank and thermostatically operated electric cooling fan (see illustrations).

1.0a Cooling system components Ц 1.05 and 1.3 litre, pre August 1985
1.0a Cooling system components Ц 1.05 and 1.3 litre, pre August 1985

1.0b Cooling system components - 1.05 and 1.3 litre, post August 1985
1.0b Cooling system components - 1.05 and 1.3 litre, post August 1985

1 Radiator
2 Fan ring
3 Expansion tank
4 Thermostat housing
5 Cover
6 O-ring
7 Thermostat
8 Hose
9 Automatic choke
10 O-ring
11 Coolant pump
12 Inner timing cover
13 Camshaft sprocket
14 Timing belt
15 Outer timing cover

1.0c Cooling system components Ц 1.6 and 1.8 litre, carburettor
1.0c Cooling system components Ц 1.6 and 1.8 litre, carburettor

1.0d Cooling system components Ц 1.8 litre, fuel injection
1.0d Cooling system components Ц 1.8 litre, fuel injection

1.0e Cooling system components - 16 valve engine
1.0e Cooling system components - 16 valve engine

Coolant circulation through the radiator is controlled by a thermostat, the location of which differs according to engine type. On 1.05 and 1.3 litre engines, it is located in a housing on the rear end of the cylinder head (left side of vehicle) below the distributor. On 1.6 and 1.8 litre engines, the thermostat is located in the base of the coolant pump housing which is mounted low down on the front of the engine (timing case end).

Fuel-injected engines incorporate an oil cooler unit which is located between the oil filter and its mounting bracket.

Cold coolant from the bottom of the radiator circulates through the bottom hose to the coolant pump, where the pump impeller forces it around the cylinder block and head passages. After cooling the cylinder bores, combustion surfaces and valve seats, the coolant reaches the cylinder head outlet and is returned to the pump via the bypass hoses when the thermostat is closed. A further cylinder head outlet allows coolant to circulate through the inlet manifold and heater matrix (with heater control on) and it is then returned to the pump.

When the coolant reaches a predetermined temperature, the thermostat opens and the coolant then circulates through the top hose to the top of the radiator. As the coolant circulates down through the radiator, it is cooled by the inrush of air when the vehicle is in forward motion, supplemented by the action of the electric cooling fan when necessary. Having reached the bottom of the radiator, the coolant is now cooled and the cycle is repeated.

The electric cooling fan is controlled by a thermo-switch located in the left-hand side of the radiator.

Air conditioning system
The air conditioning unit works on exactly the same principle as a domestic refrigerator, having a compressor, a condenser and an evaporator. The condenser is attached to the vehicle radiator system. The compressor, belt-driven from the crankshaft pulley, is installed on a bracket on the engine. The evaporator is installed in a housing under the dashboard which takes the place of the normal fresh air housing. The housing also contains a normal heat exchanger unit for warming the inlet air. The evaporator has a blower motor to circulate cold air as required.

The system is controlled by a unit on the dashboard similar to the normal heater control in appearance.

The refrigerant used is a dangerous substance in unskilled hands. As a liquid it is very cold and if allowed to touch the skin will cause cold burns. As a gas it is colourless and has no odour. Heavier than air, it displaces oxygen and can cause asphyxiation if pockets of it collect in pits or similar workplaces. It does not burn but even a lighted cigarette causes it to break down into constituent gases, some of which are poisonous to the extent of being fatal.

Precautions
Cooling system maintenance Do not remove the expansion tank filler cap or disturb any part of the cooling system whilst it is hot, as there is a very great risk of scalding. If the filler cap must be removed before the system is cool, then the pressure in the system must first be released. Cover the cap with a thick layer of cloth, to avoid scalding, and slowly unscrew the cap until a hissing sound can be heard. When the hissing has stopped, then system pressure is released. Slowly unscrew the cap until it can be removed. If more hissing sounds are heard, wait until they have stopped before unscrewing the cap completely. At all times keep well away from the filler opening.

If the engine is hot, the electric cooling fan may start rotating even if the engine is not running. Be careful to keep hands, hair and loose clothing well clear of the fan when working in the engine compartment.

Antifreeze mixture
Antifreeze mixture is poisonous. Keep it out of reach of children and pets. Never leave antifreeze lying around, it is fatal if ingested.

Do not allow antifreeze to come in contact with your skin or the painted surfaces of the vehicle. Rinse off spills immediately with plenty of water.

Air conditioning refrigerant Although the refrigerant is not itself toxic, in the presence of a naked flame (or a lighted cigarette) it forms a highly toxic gas. Liquid refrigerant spilled on the skin will cause frostbite. If refrigerant enters the eyes, rinse them with a dilute solution of boric acid and seek medical advice immediately.

In view of the above points, and of the need for specialised equipment for evacuating and recharging the system, any work which requires the disconnection of a refrigerant line must be left to a specialist.

Do not allow refrigerant lines to be exposed to temperatures above 230∞F (110∞C) - eg.

during welding or paint drying operations. Do not operate the air conditioning system if it is known to be short of refrigerant, or further damage may result.


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