Cooling System Components - Removal & Installation Volkswagen Fox G1

INTRODUCTION

Volkswagen Fox, Golf, GTI, and Jetta engines are liquid cooled, and rely on a closed system of circulating coolant to maintain an even engine temperature and help transfer heat away from the engine. To provide adequate cooling system performance over a range of temperature conditions, to supply lubrication to the system's moving parts and to prevent the buildup of mineral deposits and other contaminants, the coolant recommended for use year-round is a mixture of phosphate-free anti-freeze and clean water. The closed system becomes pressurized as its temperature increases. The pressure in turn raises the boiling point of the coolant and allows engine temperature to exceed the coolant's normal boiling point.

The coolant pump is mechanically driven by the engine, and operates whenever the engine is running. Coolant circulates through the engine to the radiator, the heat exchanger or heater core in the passenger compartment heating system, and back to the pump. On some models, coolant is also circulated through a heat exchanger in the engine's lubrication system to help moderate engine oil temperature. Before the engine is up to normal operating temperature, the flow of coolant is controlled by a thermostat. The thermostat forces coolant flow to bypass the radiator, returning directly tot he coolant pump, until the engine is warm.

A radiator cooling fan provides auxiliary air flow through the radiator. For compatibility with the transverse engine design, and to minimize power consumption, the fan is electronically operated and thermostatically controlled so that it runs only when the extra air flow is required to maintain proper coolant temperature.

COOLANT PUMP

A centrifugal-type coolant pump and its housing are mounted to the cylinder block. the pump is crankshaft driven by a V-belt, and circulates coolant through the system whenever the engine is running.

THERMOSTAT

A thermostat located in the coolant pump housing and controls coolant flow into the pump. When the is engine is cold, the thermostat is closed and coolant bypasses the radiator, recirculating from the engine directly back to the pump inlet. When the engine reaches normal operating temperature, the thermostat opens and coolant circulates through the whole system, including the radiator.

RADIATOR

The radiator is a cross-flow type constructed of an aluminum core and plastic side tanks. A translucent expansion tank, or overflow reservoir, provides for the expansion of the coolant at higher temperatures and easy monitoring of coolant level.

RADIATOR COOLING FAN

An electric radiator cooling fan, operating independently of the engine, is controlled by a thermoswitch located in the bottom of the radiator. At high coolant temperatures, the switch closes to the start the cooling fan. The cooling fan is wired directly to the battery. Any time the coolant temperature is excessive, the fan will start and continue to run until coolant temperature is in the correct range. On models with air conditioning, high refrigerant pressure can also activate the cooling fan.

On some models with gasoline engines, a cooling fan after-run system, separated by a control unit on the fuse/relay panel, runs the cooling fan for as long as 15 minutes after the engine is shut off, as a guard against starting problems which may be caused by high engine compartment temperatures.

Fluid

Use 50% phosphate-free Ethylene Glycol "G11" antifreeze (VW-ZVW 237 104) and 50% distilled water.

Quantity

7.0 qts. (6.6 L)

Checking Coolant Level

Because the expansion tank is translucent, the coolant level can be checked visually without opening the system. With the engine cold, the coolant level should be between the MIN and MAX marks on the expansion tank. (Scheme 1) If it is necessary to add coolant, remove the cap and add it to the expansion tank only.

Scheme 1

Draining & Filling Coolant

To drain the coolant, disconnect the coolant hoses. (Scheme 2) To refill the system, first install the lower radiator hoses and their clamps. Then fill the system with the coolant and water mixture until the level reaches the MAX mark on the coolant reservoir. (Scheme 3) Start the engine and let it idle, rechecking the coolant level after it has had a chance to circulate. After the engine has cooled, check the coolant level and add coolant as necessary.

Scheme 2

Scheme 3

Inspecting

Note. For drive belt adjustments see DRIVE BELTS in ADJUSTMENTS.

Twist belt to inspect sides and bottom. Belt structural damage, glazed or shiny sides caused by a loose belt, or separation caused by oil contamination are all reasons to replace a belt. (Scheme 4)

Scheme 4

Replacing

To reduce the chance of V-belt failure while driving, replacement of the belts every four years is recommended. Loosen the mounting bolts and adjust until the belt tension is very loose, the remove the belt by slipping it over the pulleys. In some cases it may be necessary to remove one V-belt to replace another. Cross section and length determine belt size. Use the old belt for comparison, or make sure that the new belt fits into the pulley groove. (Scheme 5)

With the belt off, clean the pulleys using a suitable solvent. Inspect the pulleys for wear or damage which may cause early failure of the new belt. This is also a good opportunity to inspect the belt-driven accessory, checking for bearing wear and excess play, for example. When installing the new belt, gently pry it over the pulleys. Too much force may damage the belt. Tension the belt(s), run the engine for a few minutes (at least 1500 RPM), then recheck the belt tension. See V-BELT DRIVE BELT DEFLECTION SPECIFICATIONS table in ADJUSTMENTS .

Scheme 5

COOLANT HOSES

Connections should be tight and dry. Coolant seepage indicates wither that the hose clamp is loose, that the hose is damaged, or that the connection is dirty or corroded. Hoses should be firm and springy. Replace any hose that is cracked, that has become soft and limp, or has been contaminated by oil. (Scheme 6)

Scheme 6

DRIVE BELTS

Check V-belt tension by checking the amount of deflection when the belt is pressed mid-way between two pulleys. For V-belt deflections specifications, see V-BELT DRIVE BELT DEFLECTION SPECIFICATIONS table.

V-BELT DRIVE BELT DEFLECTION SPECIFICATIONS

DRIVE BELT ROUTING

Note. See appropriate DRIVE BELT ROUTING article in ENGINE COOLING.

Scheme 7

SYSTEM PRESSURE TEST

Pressurize the system to approximately 18 psi (1.25 bar). Loss of pressure indicates leaks which should be apparent by the seepage of coolant. If the pressure drops rapidly and there is no sign of coolant leaks, the cylinder head gasket may be faulty. See appropriate ENGINE article.

CAP

To test the cap, install it on the pressure tester. Increase pressure until you hear the cap's pressure relief valve open. On all engines except the 2.0L 16-Valve engine, the valve should open at 17-19 psi (1.20-1.35 bar). On 2.0L 16-Valve engine, the relief valve should open at 19-22 psi (1.3-1.5 bar). If the cap's pressure relief valve opens above or below this range, replace the cap.

TEMPERATURE GAUGE

With the ignition on and the engine not running, disconnect the gauge wire (Yellow with Red stripe) from the sending unit in the coolant outlet on the cylinder outlet. On 16-valve engines, the sending unit is on the driver's-side end of the cylinder head. Ground the wire. This stimulates a high engine temperature signal to the gauge. If the gauge needle moves upward, the sending unit is faulty and should be replaced. If the needle still does not move, either the wire to the gauge is broken (open circuit) or the gauge is faulty.

SENDING UNIT

If the gauge reads high when the engine is cold and the ignition is switched on, disconnect the temperature sending unit wire from the sending unit. If the needle drops to a lower reading, the sending unit is faulty. If the needle does not drop, the wire or the gauge is shorted to ground.

Measure the thermostat the change in length between cold and hot conditions. (Scheme 8) Heat the thermostat in a pan of water while monitoring temperature with a thermometer. (Scheme 9)The thermostat should begin to open at approximately 185°F (85°C). At boiling temperature, approximately 212°F (100°C) the length should be at least 9/32" (7 mm) greater than the cold length measured before the use of the heated water. A thermostat which does not open the full amount should not be installed.

Scheme 8

Scheme 9

To inspect the coolant pump, first remove the V-belt. See DRIVE BELTS . Firmly grasp the coolant pump pulley and check for play in all directions. Rotate the pulley and check for play in all directions. Rotate the pulley and check that the shaft moves smoothly. Is should rotate smoothly. Inspect the pump for leaks. An occasional drop of coolant from the pump shaft is acceptable. A larger leak of a shaft that is excessively loose or noisy, indicating a worn bushing, means that the pump is faulty and should be replaced. Replace the V-belt if it is worn or damaged.

Note. When replacing the coolant pump on cars with power steering, pump and mounting brackets must be removed first. On cars with air conditioning, replacement of the coolant pump will be considerably easier if the alternator and air conditioning compressor are removed. The air conditioning compressor should be removed from its mountings and set out of the way without loosening or removing the compressor hoses.

1. Drain the cooing system. See «DRAINING & FILLING COOLANT»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__draining-filling-coolant).
2. Remove the V-belt. See «DRIVE BELTS»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__drive-belts).
3. Remove the nut and T-bolt that fastens the camshaft drive belt cover to the coolant pump. Disconnect the remaining hoses for the pump housing.
4. Disassemble the pump and housing assembly. (Scheme 10) Remove the pulley(s) from the coolant pump haft. Remove the seven bolts and washers and separate the pump from the housing.

Scheme 10

Note. The power-steering V-belt pulley attached to the coolant pump is marked with the word KLIMA. The mark faces outward (away from pump) on vehicles with air conditioning, and inward on vehicles without air conditioning.

1. Assembly is the reverse of disassembly. Use a new gasket between the coolant pump and housing. For torque specifications see «TORQUE SPECIFICATIONS»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__torque-specifications) .
2. Clean the surface of the engine block where it will be contacted by the pump housing and the O-ring. Install a new O-ring in the recess that surrounds the water outlet.
3. Loosely install the coolant pump on the engine. The two short bolts are used at the top of the pump housing. Tighten bolts to specification, see «TORQUE SPECIFICATIONS»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__torque-specifications) .

1. Drain the coolant. See «DRAINING & FILLING COOLANT»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__draining-filling-coolant) .
2. Remove the hose. Using a screwdriver, or pliers in the case of spring clamps, loosen each hose clamp and slide the clamps away from the hose ends.

Scheme 11

1. Clean the hose connections. Make sure any bits of old hose and sealer are removed. Clean with a wire brush if necessary.
2. Install the hose. Lightly coat the connections with water-resistant sealer. Place the loose hose clamps onto the hose before fitting the hose ends to the connections.
3. Position and tighten clamps. Place clamp as near to the bead as possible and at least 5/32" (4 mm) from the hose end. (Scheme 12) Tighten screw-type clamps enough to compress the hose firmly around the connections.
4. Refill the radiator. See «DRAINING & FILLING COOLANT»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__draining-filling-coolant). Run the engine until warm and check for leaks. Check again after engine has cooled.

Scheme 12

1. Drain the cooling system and disconnect the upper and lower radiator hoses. See «DRAINING & FILLING COOLANT»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__draining-filling-coolant) .
2. Disconnect the negative (-) battery cable from the battery and the harness connectors from the thermoswitch and cooling fan motor.
3. Remove the bolts from the upper radiator mounts.
4. Lift the radiator out from the top, complete with the fan and fan shroud, tilting it toward the engine.
5. To install, reverse removal procedures. Tighten to specification, see «TORQUE SPECIFICATIONS»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__torque-specifications) .

Scheme 13

1. Drain the coolant. See «DRAINING & FILLING COOLANT»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__draining-filling-coolant).
2. Remove the two thermostat housing bolts and separate the housing from the coolant pump. (Scheme 2)

1. Position the thermostat in the coolant pump housing with a new O-ring and install the thermostat housing.
2. Install bolts and tighten to specification. See «TORQUE SPECIFICATIONS»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__torque-specifications) .
3. Connect coolant hoses.
4. Fill cooling system. See «DRAINING & FILLING COOLANT»(/volkswagen/fox/g1-1987-1994/remont/cooling-system-mechanical/#cooling-system-components-removal-installation__draining-filling-coolant) .
5. Warm the engine and check for leaks. Check again after the engine has cooled.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• DRIVE BELTS
• DRIVE BELTS
• DRAINING & FILLING COOLANT
• TORQUE SPECIFICATIONS