An overheating engine can go from a warning to serious damage in a matter of minutes. Knowing what to do straight away can save you from a warped cylinder head or a blown head gasket, two of the most expensive engine repairs there are. In a hot city with heavy traffic like Surat, overheating is more common than many drivers expect, especially in older cars and in peak summer.

How to tell your car is overheating

• The temperature gauge climbs above its normal middle position, or a red temperature warning light comes on.
• Steam or smoke rises from under the bonnet.
• A sweet, syrupy smell, which is leaking coolant.
• The engine loses power, knocks or pings.
• The AC suddenly blows warmer, as some cars cut the AC to protect an overheating engine.

What to do if your car is overheating

1. Switch off the AC. It adds load to the engine and heat to the radiator.
2. Turn the heater to full heat and full fan. It feels wrong in summer, but it pulls heat away from the engine through the heater core.
3. Pull over safely as soon as you can and switch off the engine.
4. Open the bonnet from inside if it’s safe, to let heat escape. Don’t touch anything yet.
5. Never open the radiator or coolant cap while the engine is hot. The coolant is under pressure and can spray out and cause serious burns.
6. Wait at least 30 minutes for the engine to cool down.
7. Check the coolant level in the see-through reservoir once cool. If it’s low, top up with coolant, or plain water in an emergency, then get it checked.
8. If the gauge rises again, stop. Don’t keep driving; call for help or arrange for the car to be collected.

Common causes of car overheating

Low coolant or a leak

The most common cause. Look for green, pink or orange puddles under the car, white crusty marks on hoses, or a sweet smell. Leaks come from hoses, the radiator, the water pump or loose clamps.

Radiator fan not working

If the car overheats in traffic but is fine on the highway, the electric cooling fan may have failed, often because of a fuse, relay, sensor or the fan motor itself. The same fan often serves the AC condenser, so you may also notice weak AC cooling.

Faulty thermostat

The thermostat controls when coolant flows to the radiator. If it sticks closed, coolant can’t reach the radiator and the engine heats up quickly.

Clogged radiator

Old coolant leaves scale deposits inside the radiator, and dust and insects block it from outside. Either way, it can’t release heat properly.

Failing water pump

The water pump circulates coolant through the engine. A worn pump may leak from a small weep hole or simply stop moving enough coolant.

Low engine oil

Oil also carries heat away from the engine. Very low or very old oil adds to the heat load. See when to change engine oil.

Head gasket problems

White smoke from the exhaust, coolant disappearing with no visible leak, or milky engine oil can point to a damaged head gasket. This needs a workshop straight away.

How to prevent overheating

• Check the coolant level every month when the engine is cold.
• Replace coolant at the interval in your service schedule, using the type your car maker specifies.
• Get hoses, the radiator and the fan inspected at every car service.
• Keep an eye on the temperature gauge, especially in summer traffic and on hill drives.
• Don’t ignore small coolant leaks; they rarely fix themselves.

Common questions

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