Car Overheating? 6 Radiator Problems Every South African Driver Should Know

Few things are more alarming than seeing steam billowing from under your bonnet on a scorching South African summer day. Radiator problems are one of the most common causes of breakdowns on our roads, and understanding the warning signs can save you from an expensive engine repair—or worse, being stranded on the N1.

How Your Radiator Keeps Your Engine Cool

Your radiator is the heart of your car's cooling system. It circulates coolant through the engine block, absorbing heat, then releases that heat through the radiator fins as air passes through. In South Africa's extreme temperatures—especially in Gauteng, Free State, and Limpopo where summer temps regularly exceed 35°C—your cooling system works overtime.

1. Coolant Leaks: The Silent Engine Killer

A puddle of green, orange, or pink fluid under your car is a telltale sign of a coolant leak. Common leak points include:

• Radiator hoses (upper and lower)
• Radiator core or tanks
• Water pump seal
• Heater core connections

What to do: Check your coolant level regularly. If you're constantly topping up, there's a leak that needs finding. Don't ignore it—running low on coolant will overheat your engine fast.

2. Thermostat Failure

The thermostat controls when coolant flows through the radiator. When it fails stuck closed, coolant can't circulate and your engine overheats rapidly. When stuck open, your car takes forever to warm up and your heater blows cold.

Signs of thermostat trouble:

• Temperature gauge shoots to hot within minutes
• Engine never reaches normal operating temperature
• Heater doesn't blow warm air

3. Blocked or Clogged Radiator

Over time, rust, debris, and mineral deposits can clog your radiator internally. Externally, bugs, leaves, and road grime block airflow through the fins. Both reduce cooling efficiency dramatically.

Prevention tip: Flush your cooling system every 40,000 to 60,000 km. Use quality coolant mixed with distilled water—not tap water, which contains minerals that cause buildup.

4. Radiator Fan Problems

Your radiator fan kicks in when the car is stationary or moving slowly—exactly when natural airflow isn't cooling the radiator. If the fan fails, you'll overheat in traffic or at robots.

Quick test: Let your car idle until it reaches operating temperature. Listen for the fan to switch on. If the temp keeps climbing and no fan, you've found your problem.

5. Failed Water Pump

The water pump circulates coolant through the entire system. When it fails, coolant sits stagnant and your engine overheats almost immediately. Warning signs include:

• Coolant leak from the front-centre of the engine
• Whining or grinding noise from the pump area
• Steam from the radiator
• Rapid overheating

6. Blown Head Gasket

This is the one you don't want to hear. A blown head gasket allows coolant to leak into the combustion chamber or oil passages. Signs include:

• White smoke from the exhaust
• Milky residue under the oil cap
• Bubbles in the coolant reservoir
• Persistent overheating despite no visible leaks

If you suspect a head gasket issue, stop driving immediately. Continued use causes catastrophic engine damage.

What To Do If Your Car Overheats

1. Pull over safely as soon as possible
2. Turn off the AC and turn the heater to maximum (this draws heat away from the engine)
3. Don't open the bonnet immediately—let it cool for at least 15 minutes to avoid steam burns
4. Never remove the radiator cap while the engine is hot
5. Check coolant level once cool, and top up with water temporarily if needed
6. Get to a mechanic or call for roadside assistance

Find Quality Radiator and Cooling Parts at Ace Auto

Whether you need a new radiator, water pump, thermostat, cooling fan, or radiator hoses, Ace Auto Parts stocks quality new and used parts for most vehicle makes and models in South Africa. Our experienced team can help you find the right part for your vehicle—get in touch or browse our online catalogue today.

Stay cool out there, South Africa. Your engine will thank you.