Tap to Read ➤

How Often to do a Coolant Flush

Scholasticus K
An important part of a machine servicing process is that of coolant flush. As part of the periodic maintenance, it is essential that the coolant is flushed out of the radiator. Here are some suggestions and advice about flushing of coolant.
A coolant is defined as 'an agent (liquid or gas) that does the job of transferring heat from one object to another'.
In automobiles, a coolant that is in the form of a mixture of water, oil, and some other antifreeze chemicals, takes away the heat from the internal combustion and maintains suitable operating temperature of the automobile. The coolant flush thus refers to the flushing, and replacement of the coolant from the radiator of the automobile.

How Often and Why Flush It?

There are two principle reasons for this activity to be done from time to time. Most of the automobile coolants are made up of water and oil.
In such a situation, the pH level of the coolant is maintained, but over a time period, the basic-acidic balance of the coolant, which ideally should be equal, begins to change. If the level is more acidic, then the auto parts might get corroded, and if it is basic, there will be severe depositions within the car parts.
The coolant concentration is another matter that one should be worried about. Due to the usage, concentration of coolant within the car parts deteriorates, and the vehicle begins to heat up frequently.
Contamination of coolant is a very dangerous situation, and it can drastically harm the car's health. While in use, a coolant may get contaminated by several agents such as metal chips, tramp oil, salts, and even bacteria.
On the whole, frequent and timely change of coolant plays a highly instrumental role in upholding the performance of the car.
In some cases, its replacement might prove to be a bit costly, but if you look at the bright side, flushing coolant at a regular intervals proves to be beneficial in terms of engine mileage, reduction of harmful emissions, and also in avoiding car repairs.

How Often to do a Coolant Flush?

There are several factors to be considered before deciding the frequency, at which flushing of the coolant will be done:
  • Size of the engine
  • Total number of miles that are completed
  • Climate (antifreeze concerns)
  • Age of the current coolant
  • Type of coolant
  • Recommendations of manufacturers (of car as well as coolant)
On an average, manufacturers of vehicles and coolants will recommend a certain number of miles as an interval before one changes the coolant. If you are using a commercial vehicle (such as a taxi or truck), then the frequency of flushing will be more.
There are 3 types of coolants that are used around the world, namely Green Antifreeze, OAT based extended life coolants, and Hybrid OAT based coolants. All three varieties have different natures and flushing patterns.
The Green Antifreeze coolants were almost universally used before the introduction of extended life coolants. Manufacturers recommend a coolant flush after every 30,000 miles.
OAT based extended life coolants include some organic acids, and are usually dyed. These coolants are to be changed once in every five years or after 150,000 miles.
The hybrid OAT based coolant is a variant of normal OAT coolants, and is to be changed after the same time duration as that of OAT based ones. The specialty of such a coolant is that it contains silicates, which provides protection to aluminum surfaces.