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Do I Ever Need to Change My Engine Coolant?

Engine Coolant, Coolant Flush, Radiator flush, Corrosion inhibitor

Do I Ever Need to Change My Engine Coolant?

Engine Coolant, Coolant Flush, Ph Level, Antifreeze, Radiator flush, Corrosion inhibitor

This is a great question and one that is in constant debate among auto experts. Most auto manufacturers recommend changing out your engine coolant periodically, but the suggestions can range from every 12,000 miles to more than 150,000 miles. Technically speaking, in a perfect system, the chemicals in antifreeze can retain their effectiveness indefinitely. However, real life is not a perfect system. Leaks happen. Extreme weather, severe driving conditions, and traffic accidents happen. Over time, the pH level of the coolant in your radiator can change, the corrosion inhibitors get used up, and the fluid accumulates contaminants. When that happens, the components of your entire cooling system are at risk. But don’t panic! A Coolant Flush is a service that a qualified repair shop can perform along with your regular Scheduled Maintenance or as a separate service appointment.

What is Engine Coolant?

The fluid in your car’s radiator has a very specific and important job. Its main purpose is to transfer and dissipate heat generated by your engine. Generally, it is made up of a mixture of distilled water and coolant/antifreeze. The most common mixture is 50/50 but, the ratio depends on several factors:

  • Vehicle Make & Model
  • Driving Conditions
  • Manufacturer’s Suggestions
  • Type of Coolant/Antifreeze

Coolant comes in several formulas: yellow-green, red, orange, pink and blue. Check your owner’s manual to find the right coolant for your vehicle’s engine.

Distilled Water

Distilled water is a form of purified water. The stuff that comes from your tap is fine for drinking, cooking, and bathing, but it is not pure enough for your car’s coolant system. Tap water contains ions that are responsible for corrosion and scale build-up in engine components.


Most ‘antifreeze’ is made with a base of a toxic chemical called Mono Ethylene glycol (MEG), or a slightly less toxic version called Mono Propylene glycol (MPG). It is then combined with special additives that act as corrosion inhibitors. Without these additives, any metal part in your car’s cooling system that comes into contact with the coolant mixture, would rust and/or corrode, and become compromised. These additives also help control the pH level of the coolant, keeping it from becoming too acidic.

What is a Coolant Flush?

A coolant flush or radiator flush is simply draining the old, dirty coolant from your car. Then a new fluid mixture is added into the system – usually distilled water, antifreeze and a detergent specifically made for the purpose. This step may be repeated until all the contaminants are removed. Once the system is flushed, a new 50/50 mixture (or the suggested mix for your specific vehicle) is filled into your radiator.

In addition to the fluid replacement, the service technician will also brush the exterior of the radiator fins, examine the hoses, connections, and radiator cap for wear or damages.


  • Removes excess scale deposits, rust particles and other contaminants
  • New coolant lubricates the water pump, prolonging its life
  • Pressure tests look for leaks in the cooling system
  • Maintains pH levels of coolant
  • Maintains proper temperature of the engine

When Should I Change My Engine Coolant?

A good first step is to check your owner’s manual. If you have passed the suggested mileage marker for a coolant flush, then you should probably schedule a service as soon as possible. If you have a ways to go before you reach the manufacturer’s recommendation, have your mechanic check the pH level of your coolant to see how it is performing. If the test comes back as too acidic, then have them do a coolant flush while your car is there. A little preventative maintenance now could save you a ton of time and money in the long run.

Where Should I Get a Coolant Flush?

Eby’s Garage – Reliable Auto Repair in Boonsboro, MD

We service all vehicle makes and models and also perform small truck repair.

To schedule an appointment, visit us online or call our shop at (301) 432-5130.

Open M-F, 7:30AM – 5PM

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