Overheating Engine: Pull Over and Do This

 The temperature gauge climbs, a warning light appears or steam comes out from under the bonnet. An overheating engine can be badly damaged within minutes if you keep driving. Here is what to do.

The cooling system works hard under the bonnet, especially in summer.
Photo by Tomeo Sonner on Unsplash

Signs of overheating

• The temperature gauge moves into the red zone, or a warning light turns on
• Steam or smoke from under the bonnet
• A sweet smell (this can be leaking coolant)
• Loss of engine power

What to do, step by step

1. Act at once. As soon as it is safe, signal and pull over.
2. Turn off the air conditioning. Some drivers also set the heater to maximum while they look for a safe place to stop. It is uncomfortable, but it moves some heat away from the engine.
3. Switch off the engine and turn on the hazard lights.
4. Wait. Give the engine plenty of time to cool down, usually at least half an hour. If you see steam, do not open the bonnet fully until it stops.
5. Check the coolant level in the reservoir, only when the engine is completely cold.
6. Top up with the right coolant if the level is low. In an emergency, clean water will do for a short trip, but have the system corrected later.
7. Decide. If the level drops again or the temperature rises again, do not drive. Call a tow truck.

Safety note

Never open the radiator cap or the coolant cap while the engine is hot. The system is under pressure, and hot liquid can cause serious burns.

Common causes

Low coolant or a leak, a faulty thermostat, a radiator fan that does not work, a failing water pump, a blocked radiator or worn hoses.

How to prevent it

• Check the coolant level regularly, always with a cold engine
• Follow the cooling system service schedule in your manual
• Watch the temperature gauge in summer, in traffic and on long climbs

Golden tip: If the gauge starts rising, act early. A few minutes of waiting can save you an engine.

Has your car ever overheated on the road? What happened? Tell us below.

This article is for general information only. Cars differ, so always follow your owner's manual and ask a qualified mechanic if you are unsure.