QUICK FLUSH

1 If you are confident all of the cooling system components are in good working order, then it’s possible to drain, flush and refill the cooling system in under an hour. Start by releasing the bottom hose on the radiator, or unscrewing the drain plug on the underside. Release the radiator cap to let the coolant drain out.

2 Some engines have a drain tap for the coolant. It will be located around the lower half of the engine block to allow the coolant to be drained out. Some radiators and coolant pipes also have drain taps

3 Locate the two coolant hoses that are routed to the heater inside the cabin. Make sure the heater is switched to hot, then detach one of them – more coolant may drain out, so collect it in a suitable bowl.

4 Attach a hosepipe to the detached heater pipe and flush clean water through it. The water may escape out of the bottom of the radiator. If it doesn’t, detach another coolant pipe, attach a spare hose to it and drain the coolant out from here.

5 You may find you have to flush clean water through the cooling system at various points, such as an inline pressure cap, as shown here on this Toyota Mk1 MR2. The aim of this is to remove any silt and corrosion inside the system.

6 Once you are satisfied the coolant system has been sufficiently flushed through, reconnect all coolant pipes, then refill the coolant system with a diluted mixture of antifreeze and bleed it according to the instructions in your workshop manual (also see Bleeding Tips for details).