Engine Temperature Warning Light: Why Your Car Is Overheating
Written by Petro Olekhnovych, mobile mechanic in Aylesham, Kent
A red engine temperature warning light means your engine is overheating. Pull over as soon as it is safe, switch the engine off and let it cool. Driving on with this light on can cause serious and expensive engine damage.
What the engine temperature warning light looks like
The symbol is usually a thermometer sitting in wavy lines of water. That is how the Motrio garage network describes it. Check your handbook for your car’s exact symbol and colour.
Some cars also have a separate coolant level light. The RAC describes this as a yellow light, while the engine temperature light is red. Both mean you should stop, but the red one is the more urgent.
What to do the moment it comes on
Act straight away. The AA’s warning light guide for Europcar drivers says that if the light is red you should stop immediately. It warns that driving with an overheating engine can cause irreparable damage, and the engine can seize.
Turn the heater to full and switch off the air con. Motrio recommends this because it helps draw heat away from the engine while you find somewhere to stop.
Pull over somewhere safe as soon as you can.
Switch the engine off.
Do not open the bonnet if there is steam pouring out. Motrio says thick white steam from the bonnet means you should stop straight away.
Wait for the engine to cool fully before touching anything.
If you have breakdown cover, the RAC suggests calling for recovery rather than risking the engine cutting out.
Warning light on? We come to you.
Send a photo of the dashboard and your reg. We will tell you if it looks safe to drive and what it needs.
WhatsApp for a free quote Call 07563 350335
Labour £30 to £50 per hour depending on the job. Send your reg number and we will reply with a price before any work starts.
Never open a hot coolant cap
This is the most important safety point in this post. The cooling system is under pressure when hot. Motrio warns never to open the coolant cap while the engine is hot. Green Flag gives the same warning, to avoid being scalded.
Once the engine is cold, you can check the coolant level in the expansion tank against the MIN and MAX marks. Your handbook shows where the tank is and which coolant your car needs.
The RAC says that if the light comes back on after topping up, you should get the car checked. Its advice on the coolant level light is also clear: you should not drive a car with too little coolant.
Why your engine is overheating
The light is only the messenger. Something has stopped the cooling system getting rid of heat. The most likely causes, according to Motrio, are:
Low coolant. This is the most common cause, usually from a leak at the radiator, a hose or the water pump. Our guide to coolant leak signs explains what to look for.
A stuck thermostat, which stops the coolant circulating.
A cooling fan that no longer switches on.
A worn belt, or an expansion tank cap that no longer holds pressure.
The AA guide also lists a failed head gasket as a more serious possible cause.
A leaking or failing water pump is one possible cause. Our guide to water pump failure symptoms covers the signs.
For more on overheating in general, including warning signs before the light comes on, see our guide to car overheating.
Is it safe to drive with the engine temperature light on?
No. The red light means the engine is already too hot, and every mile makes damage more likely. Stop, let it cool and get it checked.
Even if the light goes off after the engine cools, the fault is still there. A car that overheated once will usually do it again until the cause is found.
What it costs to fix
It depends entirely on the cause. A loose hose clip is a very different job from a new water pump or a head gasket. Parts and labour time also vary a lot from car to car.
Stopping early is the best way to keep the cost down. An engine that has been driven while overheating can need far more work than one that was switched off quickly.
How we can help
We are a mobile mechanic, so we come to your home or workplace across East Kent, including Aylesham, Canterbury, Dover, Deal and Folkestone.
We do fault finding, so we can come out, diagnose why your engine is overheating and tell you what it needs.
We replace water pumps.
For other causes, such as a radiator, thermostat or cooling fan, we will find the fault first and then tell you what it needs.
Labour is £30-£50 per hour depending on the job and how difficult it is. Parts are extra. We agree the price with you on WhatsApp before any work starts.
Frequently asked questions
Can I drive a short distance with the temperature light on?
No. Stop as soon as it is safe and switch off. Driving an overheating engine risks serious damage.
Why is my temperature light on but the car is not steaming?
The engine can overheat before you see steam. Low coolant, a stuck thermostat or a fan fault can all trigger the light first.
Can I top up with water?
Use the coolant your handbook specifies. Only ever top up when the engine is cold.
My light went off after topping up. Am I fine?
Not necessarily. Coolant does not disappear on its own, so the cause still needs finding.
Need help? Send a WhatsApp to 07563 350335 with your car’s make and model and we’ll come to you.
Areas we cover: based in Aylesham, we come to you in Canterbury, Dover, Deal and Walmer, Sandwich and Ash, Folkestone, Wingham, Bridge and Barham, Shepherdswell, and Adisham. See all areas.
Warning light on? We come to you.
Message us on WhatsApp with your reg and postcode for a price before any work starts.
WhatsApp for a free quote Call 07563 350335
Labour £30 to £50 per hour depending on the job. Send your reg number and we will reply with a price before any work starts.
