If, however, after all this your needle does start to rise ominously in that holiday traffic jam then there are a few things you can do.
- Turn off the air conditioning. This will take some of the load from the engine so it will produce less heat.
- Switch the heater to Hot, point the air towards the windscreen and turn on the heater fan. You'll get a little heated but it will cool the engine.
- With automatic gearbox, when stationary, put the car in Neutral instead of Drive. Less heat and better coolant circulation.
- On downhill sections, leave car in Neutral and let it roll (but at no more than 10 mph). Don't turn the engine off as this will rob your ability to break and steer.
- Turning engine off for short periods may actually aggravate the problem. If the needle goes off the scale though, turn off and consider yourself broken down!
- Try and get out of the jam as soon as you can - either to park or take a side road where speeds of 20 mph plus will (hopefully) cool the engine.
- When you can do so, park for at least 30 minutes to let the engine cool then top up the water. If you are not familiar with how to do this then call the RAC or whoever, otherwise you might scald yourself or damage the engine.