Engine coolant renewal (Every 2 years (regardless of mileage)
Draining
1 It is preferable to drain the system when the coolant is cold. If it must be drained when hot, release the pressure cap very slowly having first covered it with a cloth to avoid any possibility of scalding.
2 Set the heater control to maximum heat position.
3 Place a container under the radiator and release the bottom hose or, where fitted, unscrew the radiator drain plug and allow the system to drain into the container.
The radiator drain plug (arrowed)
The radiator bottom hose clamp
Flushing
4 Provided the coolant is of the specified type, then no flushing should be necessary.
5 Where the system has been neglected however, and rust or sludge is evident at draining, then the system should be flushed through with a cold water hose inserted into the thermostat housing (thermostat removed) until the water flows clean from the disconnected bottom hose and the radiator. If, after a reasonable period, the water still does not run clear the radiator can be flushed with a good proprietary cleaning agent.
6 In severe cases, the drain plug on the cylinder block of OHV models can be unscrewed to assist sludge removal and flushing.
The cylinder block drain plug (arrowed) - OHV
On CVH models there is no drain plug on the cylinder block so you will need to detach the bottom hose.
7 If the radiator is suspected of being clogged, remove it and reverse flush it with a cold water hose. The normal coolant flow is from left to right (from the thermostat housing to the radiator) through the matrix and out of the opposite side.
8 When the coolant is being changed, it is recommended that the overflow pipe is disconnected from the expansion tank and the coolant drained from the tank. If the interior of the tank is dirty, remove it and thoroughly clean it out. Evidence of oil within the expansion tank may indicate a leaking cylinder head gasket.
Refilling
9 Reconnect the radiator and expansion tank hoses, and refit the cylinder block drain plug (OHV), or connect the bottom hose (CVH), as applicable.
10 Using the specified antifreeze (see “Lubricants and fluids”), fill the system via the expansion tank, until the coolant level reaches the “maximum” mark. Allow time for air in the system to bubble through and add more coolant if necessary. Repeat until the level does not drop and refit the cap.
11 Start the engine and run it to normal operating temperature. Once it has cooled, check and carry out any final topping-up to the expansion tank.