Keeping your car running smoothly isn’t just about fuel, tyres, and servicing; coolant plays a major role too. It’s something that many drivers forget about until there’s a problem, but the reality is simple: without the right car coolant, at the right level, your car's engine can quickly overheat, corrode, or even fail.
If you’ve ever wondered; which engine coolant for my car? How do I know if coolant is low? Or what coolant does my car need? This guide breaks down everything you need to know. No jargon. No guesswork. Just straightforward advice to help keep your vehicle running smoothly all year round.
What does coolant do in a car?
Coolant, sometimes called antifreeze, is a liquid that circulates through your engine to keep temperatures under control. It has three key jobs:
Prevent overheating
Engines generate extreme heat when running. Coolant absorbs and removes that heat, helping maintain a safe operating temperature.Protect against freezing
In wintry weather, coolant stops the liquid inside the engine from freezing, which prevents cracks, leaks, and serious damage. See our winter driving tips for more cold-weather advice.Reduce corrosion
Coolant contains additives that protect the engine and radiator from rust, limescale, and corrosion over time.
Without the right coolant mixture, your engine has to work much harder, making it less efficient and more prone to long-term wear.
How do I know if my car needs coolant?
There are several clear signs coolant is low. If you notice any of these, don’t ignore them; acting early can prevent breakdowns and costly repairs.
1. The engine temperature gauge rises
If your dashboard temperature needle creeps higher than usual, this is often the first warning that your coolant level may be low.
2. The coolant warning light comes on
Most modern vehicles have a specific coolant or engine temperature warning symbol. If this appears, pull over safely and check the level when the engine is cool.
3. You notice sweet-smelling steam
Coolant has a slightly sweet scent. Steam or vapour coming from under the bonnet, especially with that smell, can indicate overheating or a coolant leak.
4. Visible coolant leaks
Look for coloured liquid (often green, pink, orange, or blue depending on the type) under your car after parking.
5. Heater isn’t working properly
Low coolant levels can affect the car’s heating system, as the heat exchanger relies on hot coolant to warm the cabin.
Regular vehicle checks can help you catch these issues early. You can also read our guide on top tips to keep your vehicle in good condition for more practical maintenance advice.
Which coolant does my car need?
One of the biggest questions drivers ask is: which coolant for my car? The answer depends on your vehicle type, age, and manufacturer recommendations.
Coolant typically comes in three main types:
1. IAT (Inorganic Additive Technology)
Usually green.
Common in older vehicles.
Requires more frequent changes (around every 2 years).
2. OAT (Organic Acid Technology)
Commonly orange or red.
Found in newer vehicles.
Longer lasting (up to 5 years).
3. HOAT (Hybrid Organic Acid Technology)
Often yellow or pink.
A blend of IAT and OAT.
Used in many European and Asian models.
Always check your vehicle manual, as mixing the wrong type can cause sludge, corrosion, or overheating.
If you’re unsure, many manufacturers have online lookup tools where you can enter your registration number. This will confirm what coolant does my car need based on your model.
How much coolant does my car need?
Every vehicle has a different coolant capacity, typically between 5 and 12 litres, depending on engine size. You don’t need to add that much during a top-up only enough to reach the “MAX” line on the expansion tank.
However, if you are fully draining and replacing the coolant, you’ll usually need the full capacity. Again, your owner’s manual or manufacturer website will confirm exact amounts.
A few tips:
Always top up coolant when the engine is cold.
Use a 50/50 coolant-to-water mix unless your coolant is pre-mixed.
Never open the coolant cap when the engine is hot - it can release pressurised steam.
How long does coolant last in a car?
Coolant doesn’t last forever. Over time, the additives break down, reducing its ability to prevent overheating and corrosion. Typical lifespans are:
IAT: Every 2 years.
OAT: Every 5 years.
HOAT: Every 5 years.
If your coolant looks rusty, sludgy, or contaminated, it should be flushed and replaced sooner. This is especially important for electric vehicle drivers, while EVs don’t have traditional combustion engines, they still rely on coolant to manage battery temperature. You can learn more in our guide to EV maintenance and servicing.
How to drain coolant from a car
If you're comfortable doing basic vehicle maintenance, draining and replacing your coolant is manageable - but it must be done carefully.
Step-by-step:
Park the car on a flat surface and let the engine cool completely.
Place a drain pan under the radiator drain plug.
Open the radiator cap to release pressure.
Open the drain valve and allow all coolant to flow out.
Once drained, close the valve and refill with the correct coolant mix.
Run the engine with the heater on full to remove air pockets.
Re-check the levels and top up if necessary.
If you’d rather not do this yourself, most garages can carry out a coolant flush as part of routine servicing.
How to prevent coolant issues
Staying ahead of coolant problems helps protect your engine long term. A few simple habits make all the difference:
Check your coolant level monthly.
Inspect the colour - cloudy or rusty coolant needs changing.
Have your system flushed at recommended intervals.
Look out for leaks around hoses, the radiator, or the water pump.
Keep your car serviced regularly, especially before long trips or hot weather.
Final thoughts
Car engine coolant is one of the most important, and most overlooked - fluids in your car. Knowing the signs coolant is low, understanding what type your vehicle needs, and keeping your levels topped up can save you from expensive repairs and unexpected breakdowns.
Whether you are managing your personal car or a fleet, a little knowledge goes a long way. Stay ahead of maintenance, choose the right coolant, and check it regularly to keep your engine protected year-round.
