Car Overheating: Causes, Warning Signs and What To Do

An overheating engine is one of those problems that can go from minor inconvenience to catastrophic damage in a matter of minutes if handled incorrectly. The temperature gauge creeping into the red is not something to ignore and drive on with — it’s a clear signal to act immediately.

What Causes a Car to Overheat?

The most common causes include a low coolant level (due to a leak or not being topped up), a failed thermostat, a blocked radiator, a broken water pump, a burst radiator hose, or a blown head gasket. Of these, a low coolant level and a blown head gasket are the most frequently encountered on UK roads.

Warning Signs to Spot Early

• Temperature gauge moving above the normal range
• Warning light on the dashboard (usually a thermometer symbol)
• Steam or smoke from under the bonnet
• Unusual smell — a sweet smell often indicates coolant burning
• Reduced heater output (sometimes the heater produces less heat when coolant is low)

The earlier you catch it, the less damage occurs. Don’t wait for steam — act when the gauge moves.

What To Do If Your Engine Overheats

Stop driving immediately. Pull over safely and turn the engine off. Do not open the bonnet for at least 30 minutes — the cooling system is pressurised and opening the coolant cap while hot can cause serious burns.

Once cooled, check the coolant level. If it’s low and you have water available, add water to the overflow reservoir (not the cap directly) to get you to a garage. Do not add cold water to a hot engine.

If the temperature gauge returned to normal after stopping, you can try restarting, but monitor it closely and stop again at the first sign of rising temperature.

If there’s significant steam or signs of a burst hose, the vehicle needs recovery. Call Jam’s on 07369 205 703.

Prevention

Check your coolant level monthly. Coolant should be between the min and max marks on the reservoir. Have the cooling system inspected as part of your annual service — a failing thermostat or weak water pump is far cheaper to replace preventatively than after they cause engine damage.

*Need recovery due to an overheating engine? Jam’s Breakdown & Recovery operates 24/7 across Milton Keynes and surrounding areas. Call 07369 205 703.*