Cooling system maintenance, flushing (Opel Astra H)

General information

1. When using the recommended types of coolant and proper operation, the cooling system of modern engines does not require additional maintenance.

2. If, due to the circumstances, it is necessary to pour water into the system instead of antifreeze, short-term operation of the system on water (within a few days) will not cause any serious changes in its functioning. At the first opportunity, fill the system with fresh antifreeze - it will dissolve small sediment residues and light scale, the next antifreeze change should be made in a shorter period than usual.

3. During long-term operation of the cooling system on water, especially hard water, a layer of scale will inevitably form on the walls of the cooling jacket and internal channels of the radiator, which will impede the circulation of liquid and worsen the heat exchange properties of the radiator. To remove it, it is necessary to use strong chemical solvents, while there is a significant risk of damage to the radiator and cylinder head, and flushing does not provide a 100% result. Use only recommended liquids in the cooling system (see Specifications).

4. It makes sense to flush in some cases after prolonged use of the coolant without replacement, when it has significantly changed its color and dirt particles have accumulated in it, or after the use and completion of the running-in of special sealants that were added to the cooling system to localize a minor leak in the radiator.

Attention: When adding sealant, strictly follow the instructions included with it!

Flushing

5. The radiator is flushed separately from the system in order to prevent the risk of blocking the thin internal channels of its heat exchanger as a result of them becoming clogged with deposits washed out of the engine water jacket.

Note: It would be wise to also flush the heater heat exchanger separately.

6. Disconnect the upper and lower hoses from the radiator and insert a garden hose into the first hose. Turn on the water supply and continue flushing until a clear stream begins to flow from the lower hose.

7. In cases of particularly heavy contamination or obstruction of the radiator, remove the latter (see Section 7) and perform a reverse-flow flush by inserting a garden hose into the lower pipe - if you cannot achieve a positive result, take the radiator to a car service workshop for the necessary repair work.

8. Corrosion products and dense deposits are removed from the cooling system tract by chemical treatment - follow the instructions of the manufacturer of the cleaning agent you purchased.

9. To flush the engine water jacket, remove the thermostat and disconnect the lower hose from the radiator.

10. Insert a garden hose into the hole for the thermostat in the cylinder head, turn on the water supply and continue flushing until a clear stream begins to flow from the lower hose.

11. Remove the expansion tank and wash it with clean water (with soap if necessary). Clean the level marks on the walls of the tank.

12. After completing the flushing, install all removed components back into place.