What should I do if my car overheats?

If your car starts to overheat, switch the AC off, turn the heater to full hot with the fan on high, and pull over somewhere safe as soon as you can. Switch the engine off if the gauge reaches the red or you see steam, and never open the radiator or coolant tank cap while the engine is hot. Driving on with an overheating engine can warp the cylinder head or blow the head gasket.

What should you do right away?

1. Switch off the AC. It adds load on the engine and heats the air flowing into the radiator.
2. Turn the heater to its hottest setting with the fan on full, and open the windows. The heater draws heat out of the engine coolant. It is unpleasant in summer, but it can bring the temperature down.
3. Pull over safely. Indicate, move to the hard shoulder or a side road, and switch on the hazard lights. Avoid stopping in a live lane unless there is no other choice.
4. Switch the engine off if the needle is in the red, a red temperature warning is showing, or steam is coming from under the bonnet.
5. Leave the radiator cap and the coolant expansion tank cap closed. The system is under pressure, and coolant well above 100°C can spray out and cause serious burns. Wait at least 30 minutes, longer in summer, until the engine and the top radiator hose are cool to touch.
6. Once it has cooled, check the coolant level in the expansion tank against the min and max marks, and look under the car for drips or a puddle.

If the level is low, top it up with the coolant your car's manufacturer specifies. In an emergency, clean water will get you a short distance, but the mix needs correcting afterwards. If the temperature climbs again within a few minutes of driving, stop and arrange recovery.

How can you tell the engine is overheating?

Watch for the temperature needle moving above its usual position, a red thermometer symbol or warning message, steam from under the bonnet, a sweet smell of coolant, or the engine losing power. On many cars the gauge is buffered, which means the needle sits in the middle across a wide range of temperatures. By the time it moves up, the engine is already hot. Some newer BMWs have no coolant gauge at all and only show a warning message.

Why do cars overheat in Dubai summer?

The cooling system has to push engine heat into air that can be hotter than 45°C, often while the car crawls through traffic with the AC on full. Small weaknesses that might go unnoticed in a cooler climate show up here. Common causes:

• Low coolant from a leak. Hoses, the radiator, the water pump seal and the expansion tank can all crack or seep with age and heat.
• A cooling fan that has stopped. If the temperature rises in traffic and drops at speed, the electric fan or its relay is the first thing to check. Some larger engines use a fan clutch instead.
• A blocked radiator. Dust and sand pack the fins on the outside, and old coolant leaves scale inside.
• A thermostat stuck closed. Coolant cannot reach the radiator, so the engine heats up quickly even on short drives.
• A failed water pump. Many BMW engines use an electric pump that can stop with little warning, usually with a message on the dashboard. On belt-driven pumps, a leak or a whine from the front of the engine is a common sign.
• Brittle plastic parts. Most modern cars use plastic radiator end tanks and expansion tanks, and many German cars also use plastic thermostat housings and coolant pipes. Years of heating and cooling make them crack.

When is overheating serious?

If the temperature only rises in heavy traffic and drops again when you move, it is usually a fan or airflow problem. Get it fixed soon; caught early, the engine is usually fine.

It is more serious if any of these apply:

• You kept driving after the needle reached the red or steam appeared.
• White smoke with a sweet smell comes from the exhaust once the engine is warm.
• Coolant keeps disappearing with no puddle under the car.
• Bubbles rise in the expansion tank while the engine runs.
• The heater blows cold while the engine is hot, which often means the coolant is very low.
• The engine runs rough or feels down on power after it overheated.

These can point to a failed head gasket or a warped cylinder head. Both are big repairs, and stopping at the first sign of overheating is the surest way to avoid them.

How do you stop it happening again?

Check the coolant level once a month with the engine cold, and look at the colour. It should look clean, without rust or sludge. Change the coolant at the interval in your service book, and have the radiator, condenser and fan checked before summer. A small leak or a fan that only works some of the time costs far less to fix in March than on the hard shoulder in August.

If your car is running hot, WhatsApp or call us with the make, model and year and tell us what the gauge did. If it drives normally once cooled and the temperature stays steady, we can collect it for free from anywhere in Dubai during working hours and drop it back afterwards. If it overheats again within minutes, do not drive it; arrange recovery and let us know it is on the way.