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2. Flush the radiator by hosing water at mains pressure through the filler hole. If the flow through the bottom hose stub is restricted, it will be necessary to back-flush-the radiator. Push a garden hose into the bottom radiator stub (wrap it in rag to prevent leak- age). Turn on the tap and run it until the water runs out of the filler hole. In some cases it may be necessary to remove the radiator, turn it upside down and again back-flush it by hos- ing water in through the bottom hose stub. If this does not improve the flow of water and the engine persistently over- heats, consult a radiator specialist—he may be able to de-scale it using a powerful alkaline solution.

3. Clean the outside of the radiator with plenty of water and a soft-bristled brush to remove any debris blocking the airflow.

4. To flush the heater, discon- nect the two heater hoses at the engine. One will be clipped to the cylinder head or inlet mani- fold, and the other will be attached near the water pump. With the heater control on hot’, or the cylinder head water valve open, fit the mains hose to the heater hose discon- nected from the pump. (When you turn on the water there should be an unrestricted flow from the other heater hose.) Continue flusning until clear water emerges.

5. The thermostat must come out in order to flush the cylinder block. On most cars it is located under a housing at the cylinder head end of the top hose. Unbolt the housing, remove it, and scrape away the gasket round the edge of the thermostat. The thermostat should now lift out. It may, how-ever, be corroded firmly in place. If so, scraping debris from the edge of the therm o- stat, using a small screwdriver, will allow itto be lifted.

6. Disconnect the bottom radiator hose at the water pump end. Insert the mains hose in the thermostat hole and turn on the water. There should be an unrestricted flow from the bottom hose stub. Flush until clear water emerges. Reassemble by reversing the sequence.