Maintenance
How to check and change coolant (antifreeze)
Checking the coolant level safely, measuring frost protection, which coolant to use, mixing different types and the right mix ratio with water.
Coolant does not only stop freezing in winter; it also protects the engine in summer, raises the boiling point and protects the cooling system against corrosion. That is why the system should contain the right coolant all year round.
Checking the level
Look at the expansion tank when the engine is completely cold. The fluid should be between the MIN and MAX marks.
If the level keeps dropping, there is a leak somewhere. Check the hose connections, the bottom of the radiator and around the water pump. If the exhaust gives off white smoke with a sweetish smell, or there is milky, coffee-coloured foam in the oil, the head gasket may be failing; have a mechanic look at it.
Which coolant?
Do not choose coolant by colour. Products of the same colour can have different formulations. Check the specification in your manual; European cars list designations such as G11, G12, G12+ or G13, or the manufacturer's own code. Make sure that specification is printed on the bottle.
Mixing different types of coolant can cancel out their protective additives. If you are not sure, the best approach is to drain the system completely and refill it with a single type.
Mix ratio
Concentrated coolant is usually mixed half and half with distilled (demineralised) water. In most products this ratio gives protection down to about -35 °C; the exact ratio is on the bottle. Do not use tap water, as it leaves limescale. If you buy ready-mixed coolant, do not add water.
Frost protection can be measured in a few seconds with a coolant tester at a workshop or fuel station. Having it checked once before winter is enough.
You can find coolant to your car's specification in the oil, antifreeze, batteries & tyres category.
FAQ
Can I use water instead of coolant?
In an emergency, for a short time, yes, but water does not protect against freezing or corrosion; top up with the correct coolant as soon as possible.
Can coolants of different colours be mixed?
Colour alone tells you nothing. Mixing different types is not recommended; use coolant to the specification in your manual.
This guide gives general information. Torque values, fluid quantities and service intervals vary by vehicle; follow your owner's manual. If you are unsure about safety-related work, ask a mechanic.
