How long can you drive with an overheating engine? Stop now

What the warning actually means

An engine produces an enormous amount of heat. When the gauge climbs into the red, the cooling system is no longer moving that heat away fast enough, and what you do in the next minute matters.

How the cooling system protects the engine

The cooling system's whole job is to move heat away from the engine fast enough that nothing gets damaged. Continuing to drive on an overheating engine is how a coolant problem becomes an engine problem.

The heater core pulls heat away from the engine too, which is why turning the heater on full helps while you find somewhere to stop.

Common causes

• Low coolant from a leak
• A thermostat stuck closed, so coolant cannot reach the radiator
• A failing water pump
• A cooling fan that is not pulling enough air when the car is stopped or moving slowly

What to do now

1. Turn off the air conditioning. The AC compressor adds load and heat to the engine bay.
2. Turn the heater on full and roll down the windows.
3. Find a safe place to pull over as soon as possible, and shut off the engine.
4. If you see steam, do not open the hood. Wait for it to clear.
5. Wait until the engine is fully cool, ideally at least 30 minutes, before checking the coolant level.

What you see, and how urgent it is

• Temperature gauge climbing, or the warning light: urgent, follow the overheating steps now.
• Steam from under the hood: pull over and shut off the engine, and do not open the hood.
• White exhaust smoke together with overheating: can point to something more serious than the cooling system, so it needs a same-day look.
• Coolant level dropping over time: coolant should not disappear on its own, so there is a leak.

What people often get wrong

Driving on after the gauge has gone into the red to reach a destination. Continuing to drive on an overheating engine is how a coolant problem becomes an engine problem.

When the car must go to a workshop

Have the cooling system inspected by a qualified technician after an overheat. White exhaust smoke together with overheating deserves a same-day look.

Read next

• Coolant temperature light: the engine is overheating
• Car overheating in traffic or at idle: check the fan
• Car losing coolant: where is it going?

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.