Color-Coded Confusion

Don't be confused by color-coded coolants.

The two longer-life coolants—OAT and HOAT—are able to improve on traditional coolants by reducing downtime and potential environmental concerns that come with the disposal of this highly toxic substance. But at the same time, they are more expensive than a conventional coolant, and some fleets see them as an unnecessary switch from green.

Penray doesn't manufacture coolants, but the company provides this crucial inhibitor package. According to Joel Gresmer, Penray's national sales manager, power fleet division, certain additive packages, such as OATs, are perhaps not always given the proper emphasis by OEMs. "One of the premises that some of the OEMs and the manufacturers of extended life coolants have put forward is that you really don't need filtration, and you don't need additives back in the coolant until you've reached between 300,000 and 500,000 miles," he says. "We contend that that is not a proper maintenance program."

"It's not that they're recommending improper maintenance," he emphasizes. It's simply a matter of Penray's recommendation that an extended life coolant not be ignored: "We feel that cooling systems need to be maintained and tested throughout the program."


If testing is critical, where should a fleet start? Chevron's Pellet explains the dangers confronting big fleets: "There's a lot of confusion out there. For example, we have some customers that lease their equipment. Their trucks do not always come back to their shops and so things get out of their control. This includes maintaining the cooling system and the cooling system chemistries," he says.

"What we have found—and these numbers are rough—is that a quarter of a fleet may have coolant that has been over-diluted. Over-dilution with water is an easy situation to detect and correct. We recommend checking the coolant at every PM with a refractometer. A glycol-based refractometer can easily, in a ten second test, tell you if you have the glycol you think you should have," Pellet says. "And if you don't, we recommend that you correct your freeze point—there are freeze point charts on the back of every coolant or coolant concentrate that will help you make this correction."

But if your coolant has been topped off with another formula, the stakes are a little higher. This is where regular maintenance and tracking comes in, especially if there is a possibility where you think an extended life has been topped up with a conventional coolant. "You think everything is fine, but if you don't have extended life technology anymore and it's mostly conventional, you may not be adding the SCAs (supplemental coolant additives) that you should be, and you could be getting into trouble," he says. Conventional technologies require routine SCA addition to replenish depleted inhibitor, such as nitrite for cylinder liner protection. Extended life coolants, however, do not require SCA addition. "If you are not sure whether you have conventional or extended life coolant, we recommend that you test your coolant for nitrite. Be sure that your have adequate nitrite for cylinder liner protection," Pellet says.


One of the most critical components to a cooling system is its water pump. According to Carey Norris, technical services specialist, ASC Industries, there are several ways to damage a pump, one of which is by not adhering to a manufacturer's recommendations:

"Maintaining the system so that it can pressurize properly—assuring proper coolant level, radiator cap and thermostat are functioning as intended—as well as maintaining the chemistry of coolant, will fully protect the water pump," Norris says. "Ignoring the manufacturer's service intervals risks the depletion of the additives, which will promote excessive corrosion."

Luckily, he adds, "Each type of coolant, whether IAT, OAT, or HOAT, will provide a good environment for the pump when the manufacturer's intended chemistry is maintained to their specifications."


It is also critical that a fleet have a good understanding of what conventional wisdom concerning coolants should be adhered to, and what falls into the 'myth' category.

Fleet technician Jackson describes some of the buzz around the shop: "If you're using a silicate phosphate and you put it in other types, there's a popular rumor that it will turn into jelly."

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