Engine Coolant Maintenance and Common Problems

Most people understand the primary focus of antifreeze is to remove heat when the engine is running and stop water from freezing inside when it’s not. If a hard freeze occurs, the water expands and extreme damage to internal components can result. For a long time there was only one kind of antifreeze. This made service and maintenance fairly straight forward on any vehicle when referring to the cooling system.

The downside of the older ethylene glycol water mixture was its longevity and the fact it was not environmentally friendly. Manufacturers are now producing extended life coolants that are more convenient and friendlier to the environment because they last longer. Learn about the different types of engine coolant and some of the problems associated with ignoring recommended service intervals.

Ethylene Glycol Engine Coolant

Not long ago, the most popular coolant on the market was an ethylene glycol-based mixture. This is the old-fashioned green coolant that has been around since the mid 1920’s. It provided good protection throughout a wide range of temperatures and could be utilized just about anywhere in the world. The drawbacks of an ethylene glycol-based coolant are that it’s not only poisonous, but has a sweet taste known to attract animals and children. Another downside to ethylene glycol is its rate of degradation.

Cooling systems containing this type of antifreeze needed to be serviced about every three years or 30,000 miles. When these service intervals are ignored the coolant can become acidic over time and damage internal components of the cooling system. This can damage the water pump impeller or the fragile aluminum tubes contained in the heat exchanging radiator. They make test strips that can be dipped into a cool radiator that measure the overall health and condition of the fluid. There is still plenty of ethylene glycol out there as it was used on vehicles through the 90s, but has since been replaced by better technology.

Organic Acid Technology Coolant

Organic acid technology or (OAT) type antifreeze is identified by their orange to reddish color. These are considered safer anti-freezes or at least less damaging to the environment because they are phosphate free. They are also nicknamed extended life antifreeze because of their ability to remain in service for longer intervals then their predecessors. This is due to stabilizing additives like lubricants, corrosion inhibitors and pH buffers that slow down the degradation of the antifreeze and the negative effects associated with it.

Engine Coolant Problems

The correct mixture of antifreeze and water is designed to reduce the amount of lime and rust deposits that form throughout the engine cooling system. These deposits can stick to the outer walls of the various components and act as an insulator that reduces the efficiency of heat transfer. Unwanted deposits can also act as a restriction to proper flow.

Engines with high mileage and neglected coolant maintenance can develop overheating problems from these two undesirable situations. Another common problem that can develop from neglect is a leaking situation due to completely rotted out components. Things like engine block freeze plugs, metal tubes that connect rubber hoses, and aluminum core radiators can be eaten away to the point they lose their integrity and begin to leak.

Chemical Treatments and Flushing Coolant

Chemical treatments and standard cooling system flushing are two different things. The term coolant flush is often described by professional mechanics as draining the old coolant, rinsing it out with freshwater and then adding the proper mixture of new antifreeze and water to the now empty and clean system. Proper mixture and protection should be tested with a specialized coolant tester to verify the end result.

Radiator flushing chemicals are available to help remove undesirable deposits. Different brands will have varying procedures, but will often include running the engine with the chemical flush installed for a certain period of time. This allows the chemicals to soften and remove unwanted deposits from the passages, hoses and tubes throughout the system. Thorough flushing with clean water or adding a neutralizing agent is often included in the procedure that will be clearly defined on the container itself.

In conclusion, even when engine coolant maintenance is followed to the letter, it’s still possible for lime, rust, corrosion and scale to build up. Mechanics and do it yourself folks can keep an eye on this progression during maintenance services, when the engine coolant is drained. Visual inspection of the upper radiator often tells the tale of what it looks like throughout the system. Further inspection can be done with a bore scope that provides a bird’s eye view inside the cooling passages.

Moderate to heavy buildup can be removed with chemical type flushes. Following the instructions of the flush you go with is important because you don’t want to leave any inside. Just as important is following the maintenance guidelines provided by the manufacturer in the owner’s manual so extreme measures like chemical flushing will not be required. Finally, most store bought antifreeze is already premixed with water and ready to go, but read the jug to make sure.