An engine's cooling system is designed with a margin for hot weather, but in a Qatari summer that margin is small. A cooling system that is in good health copes; one with a minor weakness can tip into overheating in slow traffic on a 47 °C afternoon.
What to do if the gauge climbs
- Switch off the AC to reduce engine load.
- Turn the heater to full hot with the fan on high. It is uncomfortable, but it pulls heat from the engine.
- Pull over safely and switch off if the gauge keeps rising or a warning light appears.
- Never open the radiator or expansion tank cap while the engine is hot. The coolant is under pressure and can cause serious burns.
Parts that commonly fail first
- Coolant hoses: rubber hardens and cracks with heat cycles. See hose replacement.
- Radiator cooling fan: if the fan or its relay fails, the car may be fine on the highway but overheat in traffic.
- Water pump: the bearing or seal fails, often with a weep from a small hole on the pump body.
- Thermostat: stuck closed, it stops coolant reaching the radiator.
- Radiator: plastic end tanks crack, or the fins clog with dust and debris.
- Radiator / expansion tank cap: a weak seal lowers the system's pressure and boiling point.
Prevention
- Check the coolant level in the expansion tank (engine cold) every few weeks.
- Use the coolant type specified by the manufacturer; do not mix types.
- Change coolant at the recommended interval.
- Have hoses and the fan checked before summer.
Related: radiator hose vs water pump failure