Coolant is a mixture of antifreeze and water. As it circulates, it absorbs the intense heat generated by the combustion process in your engine. The coolant then goes through your radiator, where it releases that heat. This is a continuous process that keeps your engine at an optimal operating temperature, for good fuel economy and smooth running.
Your coolant has other protective jobs to do as it circulates through your engine. Its high alcohol content protects against freezing at low temperatures and overheating at high temperatures. Additives blended into your coolant prevent corrosion, rust and mineral deposits from forming in your cooling system.
How is a coolant change or flush performed?
Changing the coolant, which is a separate activity from a coolant flush, is done by simply draining the coolant from the radiator, refilling the engine coolant through the reservoir, and running the vehicle until it is full and free of air.
A coolant flush is much the same, but differs in that there is normally a chemical treatment additive circulated through the engine before draining the coolant. The next step in a flush is to run water into the entire cooling system, flushing out the chemical treatment, corrosion and old engine coolant.
Then the radiator and engine block, if equipped with a drain plug, will be drained completely. Once drained, the coolant reservoir is cleaned thoroughly and replaced. Finally, the engine cooling system will be refilled and bled of air.
What to be aware of with coolant flush services
There are many brands and types of coolant and engine flushing chemicals available to consumers. Many manufacturers supply a proprietary type that is designed to protect the specific materials used in the construction of the engine cooling system. They may also indicate optional recommended brands. These recommendations should be followed to help ensure the longevity of the cooling system.
Can I change the coolant myself?
The average DIYer can maintain the engine cooling system without much trouble. However, diagnosing the system when problems arise can be a daunting task if you don't understand what each component does. Changing or flushing the engine cooling system is generally safe for the moderately experienced DIYer. If cooling system issues develop after the coolant is replaced, this repair should be handed to a certified technician.