Coolant renewal (Every 2 years - regardless of mileage)

Routine maintenance and servicing / Coolant renewal (Every 2 years - regardless of mileage)

Cooling system draining Warning: Wait until the engine is cold before starting this procedure. Do not allow
antifreeze to come in contact with your skin, or with the painted surfaces of the vehicle. Rinse off spills immediately with plenty of water. Never leave antifreeze lying around in an open container, or in a puddle in the driveway or on the garage floor. Children and pets are attracted by its sweet smell, but antifreeze can be fatal if ingested.

1 With the engine completely cold, cover the expansion tank cap with a wad of rag, and slowly turn the cap anti-clockwise to relieve any pressure in the cooling system (a hissing sound will normally be heard). Wait until any pressure remaining in the system is released, then continue to turn the cap until it can be removed.

2 Move the heater control to the ‘HOT’ position. This is necessary in order to help drain the heater circuit, as a mechanical temperature valve is used in the system.

3 Position a suitable container beneath the left-hand side of the radiator, then release the retaining clip and ease the bottom hose from the radiator stub. If the hose joint has not been disturbed for some time, it will be necessary to gently twist the hose to break the joint. Do not use excessive force, or the radiator stub could be damaged. Allow the coolant to drain into the container.

4 If the coolant has been drained for a reason other than renewal, then provided it is clean and less than two years old, it can be re-used, though this is not recommended.

5 Once all the coolant has drained, reconnect the hose to the radiator and secure it in position with the retaining clip.

Cooling system flushing
6 If coolant renewal has been neglected, or if the antifreeze mixture has become diluted, then in time, the cooling system may gradually lose efficiency, as the coolant passages become restricted due to rust, scale deposits, and other sediment. The cooling system efficiency can be restored by flushing the system clean.

7 The radiator s h o u l d b e flushed independently of the engine, to avoid unnecessary contamination.

Radiator flushing
6 To flush the radiator disconnect the top and bottom hoses from the radiator, with reference to Chapter 3.

9 Insert a garden hose into the radiator top inlet. Direct a flow of clean water through the radiator, and continue flushing until clean water emerges from the radiator bottom outlet.

10 If after a reasonable period, the water still does not run clear, the radiator can be flushed with a good proprietary cooling system cleaning agent. It is important that the manufacturer’s instructions are followed carefully. If the contamination is particularly bad, remove the radiator and invert it then insert the hose in the radiator bottom outlet and reverse-flush the radiator.

Engine flushing
1 1 To flush the engine, remove the thermostat as described in Chapter 3 and leave the cover disconnected.

12 With the top hose disconnected from the radiator, insert a garden hose into the radiator top hose. Direct a clean flow of water through the engine, and continue flushing until clean water emerges from the thermostat housing in the cylinder head outlet.

13 On completion of flushing, refit the thermostat and reconnect the hoses with reference to Chapter 3.

Cooling system filling
14 Before attempting to fill the cooling system, make sure that all hoses and clips are in good condition, and that the clips are tight.

Note that an antifreeze mixture must be used all year round, to prevent corrosion of the engine components (see following sub- Section).

15 Check that the heater controls are set to “HOT”, then remove the rubber strip and plastic cover from the plenum chamber behind the engine compartment, and loosen the bleeder screw on the heater temperature control valve.

16 Slowly pour the coolant into the expansion tank. While doing this watch the heater bleeder, and tighten the screw when bubble-free water comes out. If the coolant is being renewed, begin by pouring in a couple of litres of water, followed by the correct quantity of antifreeze, then top-up with more water.

17 Once the level in the expansion tank starts to rise, squeeze the radiator top and bottom hoses to help expel any trapped air in the system. Once all the air is expelled, top-up the coolant level to the “MAX” mark and refit the expansion tank cap.

16 Start the engine and run it until it reaches normal operating temperature and the electric cooling fan switches on, then stop the engine and allow it to cool.

19 Check for leaks, particularly around disturbed components. Check the coolant level in the expansion tank, and top-up if necessary. Note that the system must be cold before an accurate level is indicated in the expansion tank. If the expansion tank cap is removed while the engine is still warm, cover the cap with a thick cloth, and unscrew the cap slowly to gradually relieve the system pressure (a hissing sound will normally be heard). Wait until any pressure remaining in the system is released, then continue to turn the cap until it can be removed.

26 Finally refit the plastic cover and rubber strip to the plenum chamber, and reset the heater controls as necessary.

Antifreeze mixture
21 The antifreeze should always be renewed at the specified intervals. This is necessary not only to maintain the antifreeze properties, but also to prevent corrosion which would otherwise occur as the corrosion inhibitors become progressively less effective.

22 Always use an ethylene-glycol based antifreeze which is suitable for use in mixedmetal cooling systems. The quantity of antifreeze and levels of protection are indicated in the Specifications.

23 Before adding antifreeze, the cooling system should be completely drained, preferably flushed, and all hoses checked for condition and security.

24 After filling with antifreeze, a label should be attached to the expansion tank, stating the type and concentration of antifreeze used, and the date installed. Any subsequent topping-up should be made with the same type and concentration of antifreeze (see illustration).

23.24 Topping up the cooling system with antifreeze

25 Do not use engine antifreeze in the windscreen/tailgate washer system, as it will cause damage to the vehicle paintwork. A screenwash additive should be added to the washer system in the quantities stated on the bottle.