COOLING SYSTEM-M.4 To Refit the Water Pump 1. Fit the backplate followed by the water pump to the cylinder block, using new joints lightly coated with suitable jointing compound. 2. Secure the water pump assembly to the cylinder block with the four setscrews. 3. Refit the fan belt and adjust to the correct tension. 4. Refit the fan using new lockwashers. Water Pump Seals Where 'Ceramic counter face water pump seals are fitted, if the engine is run without coolant, even for a few seconds, the heat build-up between the carbon seal and ceramic counter face is very rapid, resulting in the cracking of the ceramic.
This often creates the mis- understanding that the cause of leakage is due to the incorrect assembly of the sealing arrangement of the water pump. THERMOSTAT M6 To Remove the Thermostat be as stamped on the unit by the manufacturers. 3. If the unit does not function properly then a re- placement thermostat will be required, as no adjustment of these units is possible. Certain engine applications have an external bypass which incorporates a thermostat with a bypass blanking valve. This valve closes the bypass port as the thermo- stat opens directing the coolant through the radiator. (see Fig. M.7). When replacing a thermostat, the cor- rect type must be fitted.
Failure to fit the correct thermostat may result in the engine overheating. 1. Drain the coolant from the radiator. 2. Remove the water hose from the engine water out- let connection at the front of the cylinder head. 3. Remove the two nuts and washers securing the outlet connection to the thermostat housing. 4. Remove the outlet connection and joint. 5. Lift ouLthe thermostat as shown in Fig. M.6. To Test the Thermostat To Replace the Thermostat 1. Immerse the thermostat in a suitable container of water and slowly heat. An accurate thermometer should be available to check the temperature of the water as it rises. 2. Note the temperature at which the valve in the unit commences to open.
This temperature should Replacing the thermostat is a reversal of the removal procedure. A new joint should be fitted between the thermostat housing and the water outlet connection. When the radiator has been refilled with coolant, check that no leaks are visible. ------ I===I=====~ 1. Thermostat M7 2. Thermostat Bypass Valve 3. Bypass Outlet 4. Outlet to Radiator