OHC engines
Removal
1. Disconnect the ground wire from the battery and drain the fluid from the cooling system.
2. Remove the fan together with the coupling.
3. Remove the V-belt.
4. Unscrew the bolts and remove the pulley from the coolant pump.
5. Disconnect the flexible hose leading to the heater from the coolant pump.
6. Remove the flexible coolant line between the coolant pump and the radiator.
7. Unscrew the three mounting bolts and remove the timing belt cover.
8. Unscrew the three coolant pump mounting bolts and remove the pump completely.
Repair
1. Remove the pump shaft assembly with seal, precision bearing and rotor from the pump housing.
2. Remove the seal from the pump shaft and remove the precision bearing from the pump body.
3. Using a ring and a shank of the appropriate diameter and length, move the pump pulley hub on the pump shaft so that the end of the shaft protrudes 1.5 mm above the outer surface of the hub.
4. Install the new seal onto the pump shaft and into the recess in the housing.
5. Install the rotor on the pump shaft so that the gap between its blades and the pump body is 0.8 mm.
Installation
1. Clean the mating surfaces of the pump housing and engine cylinder block.
2. Install the pump together with a new gasket on the cylinder block.
3. Install the timing belt cover.
4. Connect the flexible hoses to the coolant pump, connecting the pump to the radiator and heater.
5. Install the fan.
6. Adjust the tension of the V-belt.
7. Fill the cooling system, connect the battery and check the tightness and operation of the cooling system. If necessary, top up the coolant level.
DOHC engines
DOHC Engine Cooling System Components
1 – pump pulley, 2 – water pump, 3 – pump sealing ring, 4 – heater hose branch, 5 – heater hose branch
Removal
1. Remove the ground wire from the battery.
2. To improve access to the pump on engines with a fuel injection system, remove the air intake, high-pressure chamber and air filter.
3. Drain the coolant from the cooling system.
4. Remove the drive belt.
5. Unscrew the 4 bolts securing the water pump pulley and remove the pulley.
6. Place a suitable container under the pump, unscrew the 5 pump mounting bolts and remove the pump.
7. Remove the sealing ring from the pump (indicated by the arrow). The round section water pump sealing ring must be replaced.
Installation
Installation is carried out in the reverse order of removal.
Connecting the hoses to the DOHC engine water pump housing
A – heater hose – before May 1990,
B – expansion tank hose – up to May 1990,
C – radiator hose
On models prior to May 1990, the coolant hoses were connected to the water pump housing as shown.
On models from May 1990, the heater hose (A) and expansion tank hose (B) are swapped.
If the hoses were removed on earlier models, they should be reconnected as on later models, i.e. connect the heater hose to fitting B and the expansion tank hose to fitting A. This will reduce noise from the heater due to air in the system.
V6 engines
1. Disconnect the ground wire from the battery and drain the fluid from the cooling system.
2. Remove the fan together with the coupling.
3. Remove the V-belt.
4. Unscrew the bolts and remove the pulley from the coolant pump.
5. Disconnect the lower radiator hose and heater hose from the thermostat housing.
6. Unscrew the three bolts securing the thermostat housing to the water pump.
7. Remove the housing and thermostat.
8. Remove the twelve bolts and remove the water pump. On some models, the crankshaft pulley and vibration damper must be removed to access the lower pump mounting bolts.