Engine overheating or coolant low: what should you do?
The temperature gauge creeps towards red, a red light with a thermometer comes on or steam rises from under the bonnet. An overheating engine calls for quick action. Simply driving on risks serious engine damage. In this article, XCS Automotive in Merchtem explains what to do immediately, what the possible causes are and how to prevent problems.
What does the cooling system do?
A combustion engine produces a lot of heat. The cooling system removes that heat so the engine stays at a stable temperature. A water pump circulates coolant through the engine. The fluid absorbs the heat and releases it in the radiator at the front of the car, helped by the airflow and the cooling fan. A thermostat controls how much fluid passes through the radiator.
Coolant is not ordinary water. It contains antifreeze, so it does not freeze in winter, and additives that protect the system against corrosion.
The temperature is rising: what do you do right away?
- Switch off the air conditioning to relieve the engine.
- Stop as soon as possible in a safe place and switch off the engine.
- Only open the bonnet once no more steam is coming out, and let the engine cool down.
- Never open the cap of the expansion tank or radiator while the engine is hot. The system is under pressure and hot fluid can spray out.
- After a while, with a cold engine, check the level in the expansion tank.
- Call your breakdown service or your garage before driving on.
Do not keep driving with an overheated engine. Excessive temperatures can damage the cylinder head gasket or the cylinder head. Such a repair costs many times more than the original problem.
The orange light: coolant level low
On many cars there is an orange light for a low coolant level next to the red temperature light. It means there is too little fluid in the expansion tank. Top up with a cold engine using the coolant specified for your car. If the level drops again, there is a leak somewhere and it is best to have the system checked.
Possible causes
- Leak: a leaking hose, clamp, radiator or water pump. You often see traces or a puddle under the car.
- Thermostat: a stuck thermostat that stops the fluid from passing through the radiator.
- Water pump: a faulty pump no longer circulates the fluid.
- Cooling fan: a fan that does not switch on, especially noticeable in traffic jams or when stationary.
- Dirty radiator: dirt, leaves or insects on the outside, or deposits on the inside.
- Head gasket: with a faulty head gasket, coolant can disappear without a visible leak, sometimes with white smoke from the exhaust.
What do we do?
We check the entire cooling system: the level and condition of the coolant, the hoses, the radiator, the water pump, the thermostat and the cooling fan. With a pressure test we track down leaks. Where needed we read out fault codes and check the temperature sensors. You then get a clear explanation and a price for the repair.
Diagnosis costs €83 excl. VAT per hour, repairs €75 excl. VAT per labour hour, plus parts. You get a 1-year warranty on the work carried out.
Replacing the coolant
Coolant ages. The protective additives wear out and the fluid can become contaminated. That is why many manufacturers specify replacing it after a number of years. We follow your manufacturer's schedule and use the coolant specified for your engine. We advise against mixing different types of coolant.
If the water pump is driven by the timing belt, it is often sensible to replace it together with the timing belt. That way the engine only needs to be opened once.
Electric and hybrid cars
Electric and hybrid cars also have cooling circuits, for example for the battery and the electronics. These circuits also need maintenance according to the manufacturer's instructions. Contact us with the make and model of your car, and we will tell you honestly what we can do for you.
How to prevent overheating
- Check the coolant level now and then with a cold engine, especially before a long trip.
- Look out for puddles or traces under your car.
- Glance at the temperature gauge regularly, if your car has one.
- Have the cooling system checked during servicing.
At every minor service we check the fluid levels. More on our page maintenance and repairs. For the cold months you will find extra tips in our winter checklist.
Frequently asked questions
Can I add water if I have no coolant?
In an emergency, a little water can help you get safely to the garage. Afterwards, have the system checked and filled with the right fluid, especially before winter.
How long does the engine need to cool down?
Wait until the engine has clearly cooled down before opening the cap. If in doubt, leave the cap closed and call us.
Why does my fan keep running after I switch off?
On many cars this is normal: the fan cools the engine a little longer. It can also happen on a diesel that was regenerating.
Can you collect my car?
Throughout Merchtem we collect your car free of charge. In case of overheating, we discuss together whether the car should rather be towed.
Have your cooling system checked?
Book your appointment online via make an appointment or call Jorne on 0471 46 40 17 or Quinten on 0470 56 61 21. You will find us at Stoofstraat 43 in Merchtem, open Monday to Friday from 8 am to 6 pm and on Saturday from 10 am to 5 pm. Anywhere in Merchtem, we collect your car and bring it back free of charge.