The car’s cooling system is vital to the health of an engine and though our minds turn to topping up the anti-freeze at this time of year, that sticky liquid does so much more than prevent the coolant from freezing on cold winter mornings.
Here are 10 things every car owner should know about anti-freeze and coolant.
1 – What is anti-freeze?
Anti-freeze is a glycol-based concentrated liquid that primarily prevents an engine coolant from freezing in particularly low temperatures. It is added to and diluted by an engine’s coolant (water) according to manufacturer guidelines. However, anti-freeze nowadays does a lot more, helping prevent scale build up and corrosion in the engine and improving heat transfer from the hot engine to the coolant.
2 – What is coolant?
Simply put, the coolant is the liquid that runs through an engine to keep it within its correct operating temperature range. The vast majority of modern cars use liquid cooling to maintain optimum engine temperature. The coolant is vital to an engine’s operation and long term health. If you’re buying antifreeze/coolant in a store or online, it’s important to know the difference between the two. A product labelled coolant will be a pre-mixed, ready to use solution of Antifreeze and water that you can pour straight into the cooling system. A product labelled antifreeze will be a concentrated solution, designed to be diluted with water before you add it to your cooling system.
3 – How does coolant work?
The cooling system is a closed loop where the coolant is pumped through various small channels in the engine block and cylinder head, removing heat from the metal, before passing through a radiator. Air motion through this radiator (from the car moving or a supplementary fan) removes heat from the coolant as it passes through so it is ready to cool the engine again on the next pass. A thermostat controls the flow through the engine and the latest engines vary the cooling depending on conditions to enhance efficiency.
4 – Isn’t coolant just water?
For the most part yes, though each car maker has its own set of guidelines, which you should strictly adhere to, in terms of coolant specification and anti-freeze concentration. It’s fine to top up the coolant with water when needs be, though larger top-ups and flush-outs should be done with the recommended amounts of coolant and anti-freeze.
5 – Should I worry about sludge in the coolant?
Not immediately, no. If the engine’s temperature is being controlled satisfactorily then this probably means nothing more than scale build up or the use of hard water. To ensure the coolant system is working to maximum efficiency it is advised to flush it out in this situation with a suitable cleaning agent, then refill with the recommended coolant and anti-freeze levels. If in a hard water area it’s worth investing in using distilled or deionised water.
6 – Do I need to flush out my coolant system?
Always go by the car manufacturer guidelines, but it used to be a general rule of thumb that the coolant is flushed out and replaced every two years or 32,000 kilometres (20,000 miles). With advancements in chemical compound technology this is being pushed out to as much as five years with long life coolant, but it’s always worth erring on the side of caution. There are dedicated products you can buy to aid system flushing, such as Holts Speed Flush
7 – How much anti-freeze do I add?
Again, the car manufacturers’ guidelines are the best way to go. If in doubt contact your dealer.
8 – Can I measure the concentration of anti-freeze in my coolant?
Yes, using a refractometer or a hydrometer. The former is more accurate, but much more expensive.
9 – How much energy is lost to the coolant?
This may surprise readers, but about 30 per cent of the energy released in combustion by an engine’s fuel is lost to heat. If the coolant doesn’t remove that in heat then the engine block itself could quite literally melt and deform, causing catastrophic engine failure.
10 – What can I do about an overheating engine?
If your temperature gauge is in the red or the coolant warning light is illuminated then you really do need to stop the car as soon as is safe, pull in and turn off the engine. First and foremost, the coolant level needs to be checked, but be very very careful, as it will be under pressure and incredibly hot. It’s not advised to open the radiator cap at this stage, but opening the bonnet (cautiously to avoid any steam) is not a bad idea. Allow the engine to cool before attempting to top up the coolant system and even then you may need the assistance of a mechanic to recover the vehicle and fix it. It’s not advised to drive the car if the temperature cannot be controlled, as it could lead to complete engine failure.