The needle on your car’s temperature gauge moves into the red area ad you’re in crawling traffic: here’s what to do.
If the air conditioning is on, turn it off. Shift to Neutral and speed up the engine by pressing the accelerator: this drives more air past the fan and increases coolant circulation.
Don’t pull over and turn off the engine; it will over. Do stay well behind the car ahead to avoid the heat of its exhaust. If possible, get off on a side road where you can move faster. If all else fails, turn on the heater: it pulls heat away from the engine.
When you do stop, raise the hood and let the engine cool before looking for the source of the problem. Check for a leaking he or a faulty drive belt. Look for leaves and bugs clogging the radiator or air-conditioner condenser. Clean away the debris with a brush and, if necessary, detergent and water.
Make sure the radiator cap is cool, and remove it. Check the antifreeze level (antifreeze raises the coolant boiling point). Fill the radiator and overflow reservoir with a mixture of half antifreeze, half water.
Lacking antifreeze, add water: then as soon as possible, flush the system and add new antifreeze.
Check the antifreeze concentration with a hydrometer, an inexpensive instrument sold in auto supply stores. The concentration should be between 50 and 70 percent. If not, drain the radiator and add antifreeze. If none of these measures corrects the problem, have a mechanic check the cooling-system thermostat, the radiator cap, the fan, and on cars with electric fans, the fan switch. If overheating occurs when the car is running at highway speed, have the radiator checked for clogging.