How Often Should You Service Your Car's Coolant?

By Karen Johnston July 12, 2019

Quick facts

Coolant raises the boiling point and lowers the freezing point of the water it is mixed with.
Different coolant formulations are not interchangeable. Mixing types can cause gel formation and damage.
Coolant pH degrades over time, becoming acidic and corroding aluminum engine components.
Extended-life coolant can last up to 150,000 miles but benefits from pH testing at each oil change.

A proper mixture of water and coolant protects your engine from extreme temperatures. Coolants contain lubricating properties that maintain moving parts while circulating through the cooling system, raising the boiling point and lowering the freezing point.

Service intervals depend on your vehicle's coolant type. "The extended life coolant can last 5 years and up to 150,000 miles," though industry standard practice recommends flushing every 2 years or 30,000 miles to maintain proper pH balance.

Different coolant types have distinct colors when clean:

Standard Coolant: bright green
Dexcool (GM): orange
Toyota Extended: pink
Ford Extended: yellow
VW Extended: blue
Some Extended Life variants: clear

We recommend having your coolant tested at each oil change to ensure your engine is protected year-round.

Happy Motoring!

Frequently asked questions

Common questions

What happens if the wrong coolant type is added to my vehicle?

Mixing incompatible coolant chemistries, particularly mixing OAT (organic acid technology) formulations with older HOAT or inorganic coolants, can cause the additive packages to react, forming a gel-like substance that reduces coolant flow and clogs the heater core and radiator. The color of coolant is not a reliable indicator of type since aftermarket products vary. Always use the coolant type specified in your owner's manual, and consult a technician before topping off if you are unsure what is already in the system.

Why does coolant pH matter, and how is it tested?

Fresh coolant is formulated to be slightly alkaline, which neutralizes the mild acids that form as the additive package degrades. As coolant ages, the pH drops toward acidic, and acidic coolant attacks aluminum components, including cylinder heads, water pump housings, and heater cores. pH is tested with a simple test strip or electronic tester that measures the acidity level of the coolant sample. A reading below about 7 on the scale indicates the coolant has degraded and should be flushed regardless of mileage.

Is it safe to add plain water to the coolant reservoir in an emergency?

Adding plain water in an emergency to prevent immediate overheating is acceptable, but it dilutes the coolant concentration and reduces freeze and boil protection. Tap water also introduces minerals that can leave deposits in the cooling system. Distilled water is preferable if available. The diluted coolant should be flushed and refilled with the correct mixture as soon as possible, ideally at your next shop visit, to restore full protection and proper pH balance.

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