Engine Coolant Systems

The coolant system in a vehicle helps to keep the engine running at the right temperature to allow efficient and proper vehicle functionality.

The Basics

The coolant system circulates liquid coolant through the engine and out to the radiator to perform a heat exchange to pull heat from the engine and cool it through the radiator. This heat exchange is necessary in an internal combustion engine because the heat produced by combusting fuel would cause the engine components to warp and melt if not kept at a proper temperature.

The thermostat controls the cooling fan on the radiator determining when it needs to be on or off and also connects to the driver's control panel to indicate the coolant temperature.

The coolant system also has a branch that goes into the passenger cabin called the heating coil. This is where the car’s environmental controls draw heat from. In some cases, turning on the heat can help to cool the engine.

Normal Wear

Traditional coolant has a life expectancy of 3 years or 36,000 miles because it is petroleum based and it starts to break down. Around 2005 a new coolant was developed based on a synthetic base to give it an extended life. Now coolant can last up to 100,000 miles.

Care and Maintenance

Most manufacturers highly recommend maintenance on the cooling system between 60,000 to 70,000 miles. During this time, the fluid can become corrosive and the lubricants become depleted. The combination can cause the parts of the cooling system to wear over time. On cars older than 2005, most manufacturers recommend maintenance every 36,000 miles to keep the system operating properly.

Proper care and maintenance include getting the cooling system inspected and serviced every 3 years or 36,000 miles to prevent issues from arising. AAA reports that the number 4 reason for car breakdowns is a failure in a coolant system hose. Inspection and service can illuminate these issues before they cause a breakdown.