SECTION C

Section C.1

DESCRIPTION

The circulation of the cooling water is effected by a centrifugal pump mounted in front of the cylinder block and driven by a belt from the crankshaft pulley. A thermostat is fitted in the water outlet pipe at the front end of the engine.

When filling or topping-up the radiator, do so when the engine is cold, and if possible use rain water or clean soft water. Fill up to the filler plug orifice.

The capacity of the system is given in General Data.

Section C.2

ADJUSTMENTS IN VEHICLE

Overheating may be caused by a slack fan belt, excessive carbon deposit in the cylinders, running with the ignition too far retarded, improper carburetter adjustment, a partially choked radiator causing failure of the water to circulate, or loss of water due to leakage or evaporation.

The belt should be just sufficiently tight to prevent slip, yet it should be possible to move it laterally about 1 in. (2.54 cm.). To make an adjustment, slacken the bolts 1 and 4, fig. C.2, which hold the generator in position, then raise or lower the generator until the desired tension of the belt is obtained. Securely lock the generator in position again at securing points 1 and 4, fig. C.2, when the adjustment has been made. It must be understood that there is a correct and incorrect method of fitting fan blades. The blades are not flat, but shaped, and the concave or hollow side should be the leading one, thus, when fitting to an engine the convex or arched side must always face the radiator. This convex side is further easily identified as stiffeners are pressed into the blades; they project on the concave face.

In cases of overheating, the position of the fan blades should at once be examined; make sure, after dismantling, that the fan is fitted the right way round.

Section C.3

RADIATOR

To Remove

1. Drain the cooling system.
2. Slacken the hose clip, on the upper water hose, at the thermostat housing and with the aid of a screwdriver ease the pipe off the housing extension.
3. Take off the radiator bottom hose by releasing the clips on the water pump and the heater outlet pipe.
4. Disconnect the thermometer element from the radiator header tank.
5. Take off the six nuts (three on each side) which secure the radiator to the mounting flanges and remove the radiator.
6. Inspect the radiator core for damage and test it for water leaks. Solder at the points where leakage occurs or renew if necessary.
7. Inspect the flexible mountings for wear.
8. Inspect the drain tap for leaks and renew it if necessary.
9. Test the filler cap.
10. Inspect the hose connections for deterioration and renew them if necessary.

Section C.4

THERMOSTAT

To Remove

1. Drain the cooling system (see Section C.7
2. Disconnect the water outlet hose from the outlet elbow.
3. Remove the two nuts securing the outlet elbow to the cylinder head and lift off the outlet elbow.
4. Remove the outlet elbow to cylinder head joint.
5. Lift out the thermostat, fig C.3.
6. Test the thermostat opening temperature by immersing it in water at a temperature between 158º and 167º F (70º and 75º C.). If the thermostat valve does not start to open, or the valve sticks in the fully open position, the thermostat should be renewed. No attempt should be made to repair the thermostat.
7. Clean the joint faces at the outlet elbow and at at the housing in the cylinder head.

To Replace

The installation of the thermostat is a reversal of the procedure To remove. Fit a new joint gasket between the outlet elbow and the cylinder head. In an emergency the engine can be run with the thermostat removed.

Section C.5

A temperature gauge unit, consisting of a thermal element and dial indicator is fitted to the vehicle. The thermal element is held in the radiator header tank by a gland nut. On later engines the thermal capillary is fitted to the engine. (Fig 3C). The dial indicator is situated in the instrument panel and is connected to the element by a capillary tube filled with mercury.

Damage to any of the above mentioned parts will necessitate the renewal of the complete temperature gauge unit.

Section C.6

FAN AND PUMP ASSEMBLY

To Remove

1. Remove the radiator (see Section C.3.
2. Remove the generator (see Section N).
3. Unscrew the four set bolts securing the water pump to the crankcase. Withdraw the fan and pump assembly and remove the fan belt.

To Dismantle

1. Remove the four set bolts and withdraw the fan blades from the pulley.
2. Remove the nut and washers from the pump spindle and withdraw the pulley and hub which is keyed to the spindle.
3. Remove the key and tap the spindle rearwards, complete with the impeller.
4. Remove the front bearing circlip and withdraw the dished grease retainer.
5. Remove the rubber water seal assembly and its distance-piece from the rear of the housing.
6. Drift out the front bearing using Tool No. 18G 61; the bearing distance-piece will follow.
7. To remove the rear bearing, pace the dummy bearing of Tool No. 18G 61 in the pump body, and the drift, which is piloted in the rear bearing, is screwed into it. Tap the complete assembly out through the housing of the front bearing.
8. Withdraw the felt grease seal and retainer.
9. Clean all the dismantled pump parts.
10. Inspect the spindle for wear.
11. Inspect the seals for damage and wear. It is advisable to install new seals whenever the pump has been dismantled.
12. Inspect the bearings for pits and scores. They should be renewed if evidence of excessive wear is detected. Coat the bearings with engine oil and wrap them in a clean cloth or paper until required for reassembly.

13. If the bearings do not fit properly on the pump spindle or in the body, renew the parts as required.
14. Inspect the fan belt for uneven wear or frayed fabric, and renew the belt if required.

To Reassemble

Reassembly of the fan and pump is a reversal of the procedure To dismantle. Particular note should be made of the following:- 1. Pack the bearings with the recommended grade of grease during assembly. 2. To install the bearings, assemble Tool No. 18G 61, and drive the rear bearing into its housing. The front bearing and distance piece are fitted in a similar manner. 3. Refit the fan blades to the pulley with the radiused tips of the blades leading. 4. Check to see that the bearings run freely without excessive end play, by spinning the fan.

To Replace

The installation of the fan and pump assembly is a reversal of the procedure To remove. Particular note should be made of the following:- 1. Install a new joint gasket between the pump body and the cylinder block. 2. Adjust the fan belt (see Section C.2. 3. Lubricate the pump as detailed on page Q.6.

Section C.7

DRAINING AND FLUSHING THE SYSTEM

To Drain the System

When the vehicle is to be stored, the entire cooling system should be drained to protect against corrosion and, in certain instances, freezing. To drain the system proceed as follows :-

1. With the vehicle standing on level ground, remove the radiator filler cap.
   

Caution. - As the system is pressurised, do not remove the radiator filler cap while the engine is running and always wait until the water has cooled.

If it is necessary to remove the filler cap while the engine is hot it is essential to remove it gradually, and the filler neck is provided with a shaped cam to enable this to be done.

Unscrew the cap slowly until the retaining tongues are felt to engage the small loves at the end of the filler neck cam, and wait until the pressure in the radiator is fully released before finally remove the cap.

2. Open the cylinder block and radiator drain taps. If the system contains anti-freeze mixture it should be drained into clean containers, strained and preserved for re-use.
3. Insert a length of wire into the open taps to disturb any sediment, etc., that may block the flow.

4. To prevent the possibility of operating the vehicle with the system drained, make sure that a suitable notice is placed on the vehicle or other suitable precautions taken.

To Flush the System

If an inhibitor is not used, the cooling system should be drained, cleaned and flushed at intervals depending upon the type of vehicle operation and the local water conditions. Do not use strong caustic or acid solutions for cleaning purposes because they have a detrimental effect on various parts of the system. To clean and flush the system, proceed as follows :-

1. Drain the system completely as described above.
2. With a hose pipe, or fresh quantities of clean water, flush the system through until water issuing the from the drain taps appears to be clean.

3. Allow the system to drain completely, then close the drain taps.
4. Fill the system with clean water (or anti-freeze solution), slowly, to allow air to escape past the thermostat valve, up to the bottom of the filler neck.
5. Replace the filler cap by turning it approximately 90º in a clockwise direction

Section C.8

FROST PRECAUTIONS

Care should be taken to see that the water is drained off completely, for in case of freezing it will do harm by expansion taking place, and fracture of the cylinder block may result. There are two drain taps, one of them on the right-hand side of the cylinder block, and the other at the base of the radiator. Both taps must be opened to drain the system and the vehicle must be on level ground while draining.

Freezing may occur first at the bottom of the radiator or in the lower hose connection. Ice in the hose will stop water circulation, and may cause boiling. A muff can be used to advantage, but care must be taken not to run with the muff fully closed, or boiling will result.

If a heater is fitted to the car do not resort to draining the cooling system as an alternative to the use of antifreeze. It is not possible to drain the heater unit completely by means of the cooling system drain taps.

Protection by Use of Anti-Freeze Mixture

When frost is expected or when the vehicle is to be used in very low temperatures, make sure that the

strength of the solution is, in fact, up to the strength recommended by the manufacturers, for the conditions likely to be encountered.

Only anti-freeze solutions of the ethylene glycol type are suitable for use in the cooling system. Bluecol, Shell Snowflake, and Esso Anti-freeze are recommended.

The strength of the solution must be maintained by topping-up with anti-freeze solution as necessary. Excessive topping-up with water will reduce the degree of protection afforded.

If the cooling system has to be emptied, run the mixture into a clean container and use it again.

Section C.10

MODIFIED THERMOSTAT AND FILLER CAP

Commencing at engine No. 3099 a new thermostat (Part No. 11K399) having an opening temperature of 68ºC. (154ºF.) has been introduced to suit the 7 lb. pressure radiator filler cap, and to reduce the average running temperature of the engine.