Tech solutions and real world tips
How to stop overheating?
QI'm returning a Ford Cortina MkIV to the road this year. I retired it five years ago because of a tendency to overheat. What should I do to make sure the problem doesn't recur?
Ed says
AWe'll generalise here.Cooling systems are often neglected. When recommissioning a car, or sorting a persistent problem, we recommend a comprehensive approach to the whole system.
Warm the engine, then drain the coolant. Beware: don't pull the bottom radiator hose off a hot engine, or you'll scald yourself. When cool, refill with plain water and repeat. Do this until the drained water runs clear. This may take several attempts. Next, change the thermostat. They do wear out and may fail either in the hot or cold state. Replace the water pump. As you do so, note whether coolant has crystallised or gelled in the engine waterways and take steps to remove it as far as possible. If you can find a new radiator at a good price, replace it. It'll be cheaper than having the old one recored. The thin tubes get blocked with sediment – particularly, scale in hard water areas – and standard chemical flushing agents can't remove this. Heater matrix tubes are even thinner, so bear in mind if you use the car year-round. Simple engine-driven fans, though unfashionable, are 100 per cent reliable. Those with a thermostatic clutch are not: replace if necessary. Always renew the fan belt. Electric fans are usually fine (as long as they're plugged in!) but the fan switch in the radiator wears out. Replace with one of the correct temperature. If the fuse keeps blowing and it's the right value, change the motor. Finally, change any hoses and clips that look suspect (softened, hardened, split). Test drive with plain water. When you're happy, fill with silicate coolant mixed to -18ºC.
