Opel Corsa B 1993–2000 Service and Repair Manual: Every 2 Years

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 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. Antifreeze is fatal if ingested.

1. To drain the cooling system, remove the expansion tank filler cap. Turn the cap anticlockwise until it reaches the first stop. Wait until any pressure remaining in the system is released then push the cap down, turn it anticlockwise to the second stop and lift off.

2. Position a suitable container beneath the radiator bottom hose union.

3. Slacken the hose clip and ease the hose from the radiator stub. If the hose joint has not been disturbed for some time, it will be necessary to gently manipulate 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. As no cylinder block drain plug is fitted and the radiator bottom hose union may be situated halfway up the radiator, this may not fully drain the cooling system.

5. 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.

6. Reconnect the hose and securely tighten its retaining clip on completion of draining.

Cooling system flushing

7. 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.

8. The cooling system efficiency can be restored by flushing the system clean.

9. The radiator should be flushed independently of the engine to avoid unnecessary contamination.

Radiator flushing

10. To flush the radiator, drain the cooling system then proceed as follows.

11. Slacken the retaining clips and disconnect the top and bottom hoses from the radiator.

12. 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.

13. If after a reasonable period, the water still does not run clear, the radiator can be flushed with a good proprietary cleaning agent. It is important that the manufacturers instructions are followed carefully. If the contamination is particularly bad, insert the hose in the radiator bottom outlet, and flush the radiator in reverse.

Engine flushing

14. To flush the engine, remove the thermostat, then temporarily refit the thermostat cover.

15. With the top and bottom hoses 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 radiator bottom hose.

16. On completion of flushing, refit the thermostat and reconnect the hoses.

Cooling system filling

17. 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). Also check that the radiator and cylinder block drain plugs are in place and tight.

18. Remove the expansion tank filler cap.

19. On 1.2 litre models, disconnect the heater hose from the cylinder head, on 1.3, 1.4 and later 1.6 litre engines models, disconnect the wire and unscrew the coolant temperature sender from the inlet manifold. On early 1.6, and all 1.8 and 2.0 litre models, unscrew the bleed screw which is situated in the thermostat housing cover (where no bleed screw is fitted, unscrew the temperature sender unit) (see illustrations).

On 1.2 litre models, bleed the cooling system through the cylinder head heater hose outlet

On 1.3 litre models, unscrew temperature gauge sender unit from the manifold to bleed the cooling system

20. Fill the system by slowly pouring the coolant into the expansion tank to prevent airlocks from forming.

21. If the coolant is being renewed, begin by pouring in a couple of litres of water, followed by the correct quantity of antifreeze, then topup with more water.

22. When coolant free of air bubbles emerges from the orifice, reconnect the heater hose (1.2 litre models) or refit the coolant temperature sender/bleed screw (as applicable) and tighten it securely (all other models).

23. Top-up the coolant level to the "KALT" (or "COLD") mark on the expansion tank, then refit the expansion tank cap.

24. Start the engine and run it until it reaches normal operating temperature, then stop the engine and allow it to cool.

25. 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.

Antifreeze mixture

26. 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.

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

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

29. 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.

30. Do not use engine antifreeze in the screen washer system, as it will cause damage to the vehicle paintwork. A proprietry screen should be added to the washer system in the recommended quantities.