Why does your car overheat in Dubai summer & how to prevent it

Quick answer: If the temperature gauge climbs or a warning light appears, turn off the AC, turn the cabin heater to full, and pull over as soon as it’s safe. Common causes are low coolant, a coolant leak, a failed thermostat, a weak water pump, or a cooling fan that isn’t switching on. Never open the radiator cap while the engine is hot.

Dubai’s Roads and Transport Authority runs a summer safety campaign every year urging drivers to check coolant, oil, and hoses before long trips, part of the UAE’s wider “Safe Summer” push. Road surfaces here regularly pass 60°C in direct sun, and air temperatures have touched 49°C in recent heatwaves. The UAE Ministry of Interior’s Traffic Department reported that 43% of vehicle fires in 2024 were linked to extreme heat, with Abu Dhabi and Dubai logging over 2,100 car fires combined during last year’s peak heatwave, and overheated engines were named among the leading causes.

At Munich Motor Works, we’ve repaired German, European, and performance vehicles in Al Quoz since 2009, and a hot-running engine is the top reason customers call us between June and September. Here’s what we find most often in our workshop, what causes it, and how you can reduce the risk before a small cooling system fault becomes major engine damage. 

A Case We See Every Summer

Last summer, a BMW X5 arrived with its temperature gauge pinned during evening traffic on Sheikh Zayed Road. The owner had noticed a coolant warning nearly two weeks earlier but kept topping up the reservoir instead of finding the leak. Pressure testing found a cracked expansion tank, a repair that takes under an hour when caught early. By then, weeks of running hot had damaged the cylinder head gasket, turning a small job into a major repair.

This pattern repeats every summer. A small leak gets ignored because the car “still feels normal,” and it ends up costing far more than the original fix would have.

Why Heat Hits the Cooling System Harder in Dubai

An engine runs at roughly 90°C to 105°C normally, and the radiator pushes that heat into the surrounding air. When the air itself is 45°C and the asphalt underneath is 60°C or hotter, there’s far less difference for the radiator to work with. Stop and go traffic on Al Khail Road or Hessa Street makes it worse, since airflow drops and the fan has to do all the work, and running the AC adds another layer since its condenser sits directly in front of the radiator.

There’s also a less obvious problem called heat soak. After you park and switch off the engine, coolant stops circulating, but the block and cylinder head stay extremely hot for a while, and that trapped heat keeps spreading through the system. This is why plastic expansion tanks and hose fittings often crack after parking rather than while driving.

The Main Causes of a Hot-Running Engine

Low coolant or a coolant leak. 

Coolant carries heat from the engine block to the radiator. A crack in a hose, the radiator, the coolant reservoir (also called the expansion tank), or the water pump lets coolant escape, and once the level drops too far, the system can’t move enough heat anymore. Some leaks only show up under full operating pressure, which is why having the cooling system pressure tested finds what a visual check misses.

Old or wrong coolant. 

Coolant additives raise the boiling point and protect metal parts from corrosion. A proper 50/50 coolant and water mix boils at around 108°C instead of 100°C for plain water, which matters in Dubai heat. A worn radiator cap may no longer hold the correct system pressure, allowing coolant to boil earlier than it should even when the rest of the cooling system is working normally. BMW now specifies its own Lifetime Coolant (LC) formula, having phased out the older GS 94000 designation, while Mercedes-Benz models built after 2014 require the pink MB 325.5 or 326.5 spec rather than the older blue MB 325.0. Using the wrong type, or coolant left in for years, loses the corrosion protection these specs are built around.

Thermostat failure.

The thermostat controls how much coolant reaches the radiator. If it sticks closed, coolant stops circulating and temperature can spike within a few kilometres, a common failure point on BMW, Mercedes, Audi, and Volkswagen models with electronic thermostats.

Water pump failure. 

Water pump bearings, seals, or plastic impellers eventually wear out. Once circulation slows, heat builds rapidly, especially in slow moving traffic where airflow through the radiator is already limited. Several German engines use a plastic impeller that turns brittle after years of underhood heat, a known weak point.

Cooling fan failure. 

At low speed or idling near Al Quoz or Business Bay, the car depends on the electric cooling fan to pull air through the radiator. On most modern German cars, the fan doesn’t just switch on by itself, the ECU reads the coolant temperature sensor and decides when to activate it through a control module or relay. A classic symptom is temperature staying normal on the highway but climbing fast the moment traffic stops.

During June and July, we regularly see cars where the radiator and thermostat are in good condition but the fan never activates because of a failed control module or relay. Drivers often assume the radiator itself is blocked when the real fault lies in the electronics telling the fan to run.

A blocked or damaged radiator. 

Dust and fine sand collect on radiator fins over time and cut down airflow. Add a bent fin, internal corrosion, or old coolant carrying rust and mineral deposits, and the radiator can’t release heat efficiently no matter how healthy the rest of the system is.

Cooling System Issues by Brand

From what we see in our workshop, BMWs most often arrive with cracked expansion tanks caused by years of heat cycling, while Audi and Volkswagen models are more likely to develop intermittent thermostat or water pump faults that only appear once the engine reaches operating temperature. 

What to Do If the Gauge Spikes

1. Turn off the AC immediately, it adds load the engine doesn’t need.
2. Turn the cabin heater to maximum. It pulls heat away from the engine and buys you time.
3. Pull over somewhere safe, ideally in shade, and switch off the engine.
4. Let it cool for at least 30 minutes before touching anything.
5. Never open the radiator or reservoir cap while hot, the system is pressurized.
6. If coolant is low with no visible leak, or the problem repeats, have the car towed to a workshop rather than driving on.

Warning Signs and What They Mean

Preventing It Before Summer Hits

Get the cooling system pressure tested before May, since this catches small leaks before they become roadside breakdowns. A radiator inspection or repair is worth booking if your coolant level keeps dropping, even without a visible puddle. If your AC has started blowing warm air alongside a rising gauge, the two problems are often connected, since both draw on the same system. And if the engine has been running hot repeatedly, an<astyle=”color: #1fb3a5;” href=”https://munichmotorworks.ae/services/car-engine-repair/”> engine inspection can catch head gasket stress before it becomes a full repair.

Summer Cooling System Checklist

Часто задаваемые вопросы

Why does my car only run hot in traffic? 

At low speed, little air passes through the radiator, so the fan does the work. A weak fan, relay, or control module usually shows up first in traffic, not on the highway.

Can I keep driving if the gauge is high but not red? 

Pull over and check instead. Damage often happens within minutes and can’t be undone once the head gasket is affected.

Why is coolant dropping with no visible leak? 

Some leaks only appear under full system pressure, which a pressure test finds and a visual check won’t.

How often should I check coolant in summer? 

Monthly, and before a long drive between emirates.

Does adding water fix the problem? 

It gets you to safety in an emergency but lowers the boiling point and skips corrosion protection. Replace it with the correct mix as soon as you can.

If your gauge has been rising, your coolant keeps dropping, or your AC starts blowing warm in traffic, get the cooling system inspected before the next hot spell. At Munich Motor Works in Al Quoz, our technicians check the complete system using manufacturer level diagnostic equipment, pressure testing tools, and OEM specifications for BMW, Mercedes-Benz, Audi, Porsche, Volkswagen, and Land Rover. Catching a leaking hose, failing thermostat, weak water pump, or cooling fan fault early is usually the difference between a routine repair and major engine damage that leaves your vehicle off the road.