- What You Notice Before You Act
- Immediate On-Road Steps When The Engine Overheats
- What To Do After The Engine Has Cooled Down
- Common Causes Of Engine Overheating
- What The Workshop Should Check After An Overheat Incident
- Habits That Help Prevent Overheating
- Key Do’s and Don’ts To Remember
An overheating engine is one of those problems you must treat as an emergency, not a “maybe it’s fine” warning. A few minutes of driving with the temperature in the red can turn a simple cooling-system repair into a ruined head gasket or even a destroyed engine. This guide walks through what to do immediately on the road when the temperature climbs, what to check later at the workshop, the most common causes of overheating, and simple habits to reduce the risk in everyday driving.
What You Notice Before You Act
Typical warning signs:
Temperature gauge climbing close to the red zone or a clear “Engine Overheating” message on the cluster.
White steam (not dark smoke) coming from under the hood, often with a hot coolant smell.
Loss of power, or the A/C cutting off automatically in some modern cars to reduce engine load.
What you must not do:
Do not ignore the gauge and keep driving, hoping it will “sort itself out”; even a few extra minutes in the red can seriously damage the engine.
Do not open the radiator cap or coolant reservoir immediately while the engine is very hot; pressurised hot coolant can spray out and cause severe burns.
Immediate On-Road Steps When The Engine Overheats
While still moving:
Switch off the A/C to reduce load and heat on the engine.
Turn the cabin heater to maximum hot and fan speed if possible; it can help dump some heat from the engine into the cabin.
If the temperature keeps climbing:
Signal and move calmly to the right-most lane or shoulder; avoid abrupt movements that create extra risk in traffic.
Stop in a safe place away from fast-moving traffic.
Switch off the engine immediately, but you can leave the ignition in accessory mode if the electric cooling fans are still running.
After you stop:
Release the hood latch inside, then carefully open the hood from the outside, watching for steam.
Let the car sit and cool down for at least 15–30 minutes; do not touch hoses or the radiator cap while they’re still very hot.
What To Do After The Engine Has Cooled Down
Check coolant level:
Once the engine bay is warm rather than burning hot and there is no visible steam:
Look at the markings on the translucent coolant reservoir (MIN/MAX).
If the level is very low or empty, that’s a strong sign of a leak or abnormal coolant loss.
Topping up in an emergency:
If you absolutely must move the car a short distance to reach a nearby workshop:
Avoid opening the main radiator cap while hot.
Add fluid only into the coolant reservoir slowly, ideally using proper coolant, or clean water in an emergency just to reach the garage.
Remember this is a temporary measure; mixing tap water and old coolant long-term is not ideal.
When you should not drive further:
If the temperature gauge returns to the red soon after restarting.
If you can see coolant pouring or dripping heavily from the radiator, hoses, or water pump.
If you hear unusual knocking or ticking noises from the top of the engine, suggesting possible internal damage.
In those cases, the safest move is to call for a flatbed or recovery truck instead of risking further driving.
Common Causes Of Engine Overheating
Cooling system issues:
Low coolant level caused by:
Leaks in the radiator.
Old or cracked hoses.
Water-pump, radiator cap, or gasket leaks.
Clogged radiator:
Internal corrosion or sediment blocking coolant channels.
External blockage from dirt, insects, or bent fins reducing airflow.
Stuck thermostat (thermostatic valve):
If stuck closed, it prevents coolant from circulating properly through the radiator.
Airflow and fan failures:
Electric cooling fans not working due to:
Blown fuses or failed relays.
Faulty temperature sensor or control unit.
On older vehicles with mechanical fans, a failed fan clutch or damaged fan blades.
Additional factors:
Heavy towing or carrying a very heavy load in hot weather with a marginal cooling system.
Old or low engine oil:
Oil also helps carry heat away from engine components; low or degraded oil can increase operating temperatures.
What The Workshop Should Check After An Overheat Incident
Full cooling system inspection:
Pressure test of the cooling system to detect hidden leaks.
Radiator inspection:
Inside: checking for rust, sludge, or blockage.
Outside: looking for stone damage, bent fins, or restricted airflow.
Thermostat function test to confirm it opens at the correct temperature.
Fans and electrics:
Confirm that the cooling fans activate at the correct temperature.
Check associated fuses, relays, wiring, and temperature sensors.
Possible engine damage:
Oil inspection to ensure there’s no coolant mixing (milky, coffee-coloured oil can indicate head gasket issues).
Compression or leak-down tests if the engine suffered severe overheating, to check for head gasket or internal damage.
Habits That Help Prevent Overheating
Cooling system maintenance:
Replace coolant at intervals specified by the manufacturer; don’t rely on plain water long-term, especially in hot climates.
Periodically inspect hoses, the radiator, and the reservoir for cracks, swelling, or staining that suggests leaks.
Monitoring while driving:
Get into the habit of glancing at the temperature gauge occasionally, especially:
In heavy summer traffic.
On long uphill climbs.
When towing or heavily loaded.
Pay attention to any hot coolant smells or light steam from the front of the car.
Driving style:
Avoid sustained, aggressive driving at high RPM in very hot conditions with a car that hasn’t had its cooling system checked in a while.
When driving in mountains or towing:
Use lower gears where appropriate to avoid lugging the engine.
Take short breaks to let temperatures stabilise if you see the gauge creeping higher.
Key Do’s and Don’ts To Remember
Do:
Stop safely as soon as you see the temperature near the red or a clear overheat warning.
Let the engine cool before touching caps or hoses.
Have the cooling system professionally inspected if overheating happens even once; recurring issues are a red flag.
Don’t:
Don’t open the radiator cap when the engine is hot, even if you’re impatient.
Don’t keep driving long distances with a hot engine in the hope it will cool down.
Don’t play with fan wiring or sensors without proper knowledge; an intermittent fix may fail again at the worst moment.
