When to Change your Engine Coolant

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Keep it Cool
Making sure that your car's engine is running right and is properly maintained is extremely important for the continued efficient operation of your daily driver. Without properly servicing your coolant system, you risk your engine overheating and leaving you stranded. There was a time when it wasn't unusual to see a car pulled off by the side of the road with the hood up and hot steam pouring out all over the place. Thanks to advanced automobile technology today, seeing a car overheating is a rare occurrence.

Engine Coolant History

Ever since internal combustion engines appeared in motor cars somewhere around 1876, spark plugs have been igniting fuel in controlled explosions in cylinders to create the energy to move cars forward. But internal combustion produces a lot of heat, enough heat to destroy your car engine if uncontrolled. This led to the invention of a sort of circulatory system to absorb engine heat. The first engine coolant was water that was cooled through a radiator and fan so that it could be recycled through the cooling system, pushed by a water pump to keep the fluid moving.
 
The first real antifreeze was ethylene glycol which has a boiling point of 386 degrees, well above water, and a freezing point of 10 degrees, well below water. Though it offers a wide range of functionality, antifreeze (also known as engine coolant) does not conduct heat as efficiently as water. But when mixed together in equal parts, water and ethylene glycol presents a superior way to keep an engine cool. However, when liquid comes in contact with engines made from metal, that metal corrodes over time.
To fight engine corrosion and rust, inhibitors were introduced to the mixture to make the liquid coolant alkaline. Eventually, with use over time, the coolant mixture becomes more acidic and needs to be flushed out and changed about every 30,000 miles.
 
To make coolant last longer, in the 1980s, automakers developed Organic Acid Technology (OAT) coolants using a mix of nitrate, borate, silicate or phosphate to create an antifreeze that would last for up to 150,000 miles before it needs to be flushed and changed. Hybrid Organic Acid Technology (HOAT) is an even better coolant, using a chemical composition that keeps corrosion and rust at bay. It is very effective at both very low and high temperatures and can last over five years before it needs to be changed.

What Coolant to Use

It is important to know that conventional coolant and OAT or HOAT coolants should not be mixed. The chemical compositions are different enough that mixing them will lower their lifespan and possibly gunk up the cooling system, even if you have the system professionally flushed.
 
When you purchase a new car, always check with the Owner's Manual for the specific type of coolant to use and to find out how often you will need to have the engine coolant system serviced. Some automakers suggest that you have the engine coolant system completely flushed and refilled with new coolant/antifreeze every 30,000 miles. 

Depending on the make and model of vehicle, this service is recommended in your Owner's Manual every 30,000 to 50,000, or even up to 150,000 miles or 15 years. Some manufacturers recommend servicing the vehicle more often if your car, truck, or SUV has been subjected to severe service due to things like frequent towing, which can generate more heat.
 
If your engine coolant system develops a leak due to a faulty water pump or radiator hose, the loss of fluid will cause the engine to overheat.
What to do when your Engine Overheats
If your engine overheats and steam is pouring from under the hood, pull your car well off the road where it is safe and turn off the engine. If this happens at night, try to park in a well-lit area. If you get really lucky, pull into a gas station. If you are nowhere near a service center, and have emergency roadside assistance, call them right away for a tow truck.




If getting your car towed is not an option and you have a gallon of the proper engine coolant in the trunk, first, let the vehicle sit and cool down completely. Pop the hood with the latch found inside the cabin but do not touch the radiator cap. Once the engine is completely cool, check the coolant/antifreeze reservoir. This will be a plastic tank near the radiator. If it is low or empty, refill it with the automaker's recommended coolant. If the tank was completely empty, it is likely that your coolant system has a leak. Look for a puddle of antifreeze on the ground or evidence of liquid near the radiator hoses, cap, or from the bottom of the radiator.

With the reservoir full, even with a leak, you should be able to drive the car to a service station to replace the water pump or hose that is causing the leak. It is safer to get the car towed because driving the vehicle with a compromised engine coolant system can damage the engine, causing costly repairs. 
Here are three of the most common reasons that your car is overheating:

A Failing Thermostat
When you are driving, coolant circulates in the engine and a thermostat acts as a heat-sensitive valve that opens the flow of coolant to the radiator. If the thermostat fails, the coolant in the engine gets hotter and hotter, leading to overheating.
 Blocked Airflow
Air is constantly being forced through the radiator while you are driving to keep the fluid cool. However, if the radiator becomes blocked by leaves, mud, bugs, road debris or snow, airflow is blocked, and the coolant gets hot fast.
 A Leaking Water Pump or Hose
Water pumps and hoses eventually wear out and need to be replaced but as coolant deteriorates it can also cause rust to build up in the fluid, degrading the seals in the pump and causing it to leak. Old hoses can also become brittle and spring a leak.
Tips for Maintaining your Coolant System
  • Make sure your coolant level is checked every time you get an oil change every 3,000 to 5,000 miles. Have the service technician look at the coolant for signs of dirt or rust. Coolant that looks cloudy or rusty needs to be replaced.
  • Coolant must be replaced as recommended by the automaker. Check your Owner's Manual and always use the chemical type of coolant specified by the manufacturer. Using the wrong coolant can damage the engine cooling system.
  • Coolant becomes more acidic over time and can lose its ability to inhibit rust. Corrosion can damage your radiator, water pump, thermostat, and hoses, causing the engine to overheat. The system can be checked with test strips that measure acidity as well as with a hydrometer that measures the effectiveness of the engine coolant/antifreeze.


 
Let Lithia Help
Let our factory-trained service technicians test your engine coolant for alkalinity every time we change your vehicle's oil. If an engine coolant flush is recommended, it is important to know that simply draining the radiator only removes around two thirds of the coolant in the system. Our state-of-the-art service centers include coolant exchange machines that tap into the system to extract all the old fluid, replacing it with the factory-recommended new coolant/antifreeze that is right for your vehicle.