Keeping Cool

From water quality to coolant choices to owning a mixed fleet of light duty vehicles, recommended maintenance tips are as simple as they seem. "You are talking about gas or small diesel solid block engines. Those vehicles will come with recommendations in the owner manuals that include what kind of coolant to use and when to change it out," says Frank Cook, Ph.D., senior vice president for Old World Industries, Inc. "It boils down to following the vehicle manufacturer's recommendations."


When selecting a coolant to use in your vehicle, "The world breaks down into two different kinds of coolant: conventional, inorganic inhibitor systems which will last two or three years before they have to be changed out; or extended life coolants which last 100,000 to 150,000 miles before they have to be changed out," says Cook.

According to Jim Roberts, technical service specialist for Shell Lubricants, "In light duty, there is a real fragmentation between Ford and Chrysler vs. General Motors (GM).

"Ford and Chrysler have their coolant, which is a hybrid coolant that uses nitrite and silicate. They don't recommend DEX- COOL™ and GM doesn't recommend the hybrid," he says. "It is very difficult for a mixed fleet to meet the specific requirements of the different OEMs--there is no one coolant that is recommended by all the automotive companies."

Roberts cautions maintenance managers that just because the coolant in your vehicles is one color, don't automatically assume that the orange coolant you buy is the same coolant specified by the manufacturer.

"Fleets either buy the different types of coolants recommended by the OEM or they will just not worry that much about the warranty period and go to one coolant--which could potentially cause problems," he says. "One problem can lead to many problems."


"Does the coolant cause corrosion, overheating, sludge or does it eat away at the gaskets? My answer would be no. The coolant is not doing that," says Roberts.

"Being a coolant supplier, we work cloesely with equipment manufacturers to provide coolants meeting their specifications. They know that the coolants that are provided work in their equipment. If you have a cooling system issue, it isn't necesssarily a coolant failure.

"Coolant just doesn't quit working unless perhaps it has gone beyond its coolant lifespan. If you are talking about issues that happen in the system, they are generally either maintenance related or mechanically related," he says.

Roberts points out these key issues to watch for:

  • Low coolant levels--if the coolant levels aren't maintained you may get aeration, corrosion and then the corrosive metals can disperse throughout the system and plug up the radiator or the heater core.
  • A bad radiator cap is another problem. If your radiator cap isn't holding pressure you will lose coolant, your coolant will boil over or you can have aeration as well.
  • A big problem is coolant that is over- or under-concentrated. If you are finding that the coolant level is always low and you are constantly putting in straight antifreeze or straight water, then you are losing either freeze protection or heat transfer or even corrosion inhibitors.

Roberts wants maintenance managers to understand that cooling system problems or component failures aren't necessarily their fault.

"Situations where people complain that their coolant is eating their gasket or issues like that--those aren't normal issues. These issues are usually anomalies due to some kind of cooling system design failure or function.

"Manufacturers test and approve the coolants, but there are real world situations that take the cooling system and coolant out of the range in which it was evaluated," he says. "That's when things can start going wrong; if the design has changed or if the cooling system is faulty, it's something that happens to make the coolant no longer able to function."


Running the perfect mixture through your cooling system is one way to help guarantee top performance from your vehicles.

Cook says to find the specifications, look to the owner's manual of each vehicle.

"Most manuals recommend that you keep your coolant at a 50/50 level and that you change it out over a certain amount of time."

According to International Lubricants, Inc. ( ILI), manufacturer of Kool-It® and LUBEGARD automotive products, studies show that most cars on the road have cooling systems that do not contain 50/50 water/antifreeze ratio due to lack of maintenance. ILI suggests that different additives can benefit cooling systems that don't maintain the proper ratio.

"The additives help minimize potential corrosion by maintaining adequate pH levels. Even if the antifreeze already contains surfactant additives, the use of these additional additives is usually beneficial because most cars are shortchanged on the 50/50 water/coolant mix," says Kristen Clark, marketing manager for ILI.


Water quality is an issue manufacturers deal with regularly. Most OEMs recommend distilled water.

"All of the OEMs have water quality requirements relating to hardness of the water, the calcium, magnesium, sulfate and chloride levels. Distilled water is a good choice because it doesn't have any of those things. Also, good tap water could be a sufficient choice--it's things like well water and ditch water that won't meet the spec's," Roberts says.

Water is important because it can affect the pH levels, cause scale, deposits, or even add corrosive elements to the coolant

According to Shell's Roberts, when scale and deposits are formed, you reduce heat transfer, which will lead to overheating.

ILI says the debate has raged for years within the industry as to whether distilled water is best to use in a cooling system. Although plenty of OEMs actually require the use of distilled water in their vehicles' cooling systems under the threat of a possible warranty violation, ILI said that the insistence upon the use of distilled water is wrong.

"Their argument is that while it is true that distilled water's purity prevents electrolysis and scale/deposit formation, it unfortunately comes with a potentially damaging side effect," Pat Burrow, technical product manager from ILI says.

Burrows explains that during the distillation process, water is vaporized so all its impurities are left behind. These impurities include a number of minerals including calcium and magnesium, the two components that make water hard. The water is then condensed back into its liquid phase, so the result is pure water. The problem is that when water is distilled, the resulting solution is composed of chemically imbalanced ions.

"This leaves distilled water 'electrochemically hungry' so it will actually strip electrons from the metals in a cooling system as it attempts to chemically re-balance itself," he says.

"The negative effects of tap water can be greatly reduced by using an additive which contains a polymer dispersant. ILI's Kool-It® Supreme Coolant Treatment contains polymer dispersants which encases & floats calcium, etc., keeping these particles in the system, liquid," says Burrows.

The solution?

"Many experts we've spoken to insist that the use of purified water is indeed preferred to prevent the possibility of other forms of contamination," says Burrows.


"Engine coolant is very vital to maintain temperature levels for these high tech engines to get the most performance out of the vehicle," says Bob Young, project manager for Dunn and Bybee Tool Company, Inc. "When the coolant levels aren't maintained, it is important to remember the effect it can have on other components."

"You can't reverse the damage--all you can do is get it clean, patch it up and start brushing. If there are particles floating around, about all you can do is a flush and fill and put in new, good coolant," says Cook.

"Anything bad in the system will only make it worse. Corrosion metals can catalyze the oxidation of the coolant even faster, but the point is, you shouldn't have all of these things that tend to catalyze and further degrade the coolant in the first place," warns Roberts.

The biggest concern Cook sees that if fleets do let the cooling systems in their vehicles become bad enough, replacing the radiator "is a pretty big maintenance expense when the problem isn't even supposed to occur."