If you feel coolants are a confounding and challenging piece of your fleet’s maintenance program to master, you’re not alone.
“Coolants are the least understood truck fluid,” says Brad Jordan, technical services manager for coolants with Shell Lubricants. But coolants are too important to ignore. Paul Cigala, commercial vehicle lubrication applications engineer with ExxonMobil, says 40% of on-highway breakdowns “have some kind of relationship to coolant.”
The marketplace is awash with offerings of various quality and abilities. Some extended life coolants promise to last as long as you’ll own the truck, while others need additives to be replenished. Even industry-led attempts to simplify coolant selection criteria by standardizing color can’t be fully trusted, as not all suppliers adhere to the recommendations.
Today’s Trucking spoke to coolant experts to glean some tips on how fleet owners and maintenance managers can enhance their coolant program and reduce the risk of costly contamination.
Start with the right coolant
With such a vast selection of coolants of various capabilities available in the market, the Technology & Maintenance Council of the American Trucking Associations attempted to bring clarity to end users through a recommended color scheme. Coolants were to be dyed a certain color based on their specification to simplify the selection process.
In general: conventional low-silicate coolants are green; fully formulated ethylene coolants purple or pink; fully formulated propylene glycol products blue; and organic acid technology (OAT) coolants red. But the color-coding plan was a recommendation – not a requirement – and not all suppliers follow it.
“Color isn’t everything,” notes Cigala. “You can make it any color you want.”
“Color is a good way to differentiate between coolants, but it’s not always 100% reliable.”Brad Jordan, Shell Lubricants
Shell’s Jordan notes suppliers from outside North America are less likely to follow the TMC color guidelines, and that with newer extended life coolants (ELCs), recommended to be red, “we see all kinds of variations. Orange, yellow, etc. Color is a good way to differentiate between coolants, but it’s not always 100% reliable.”
When selecting a coolant, rather than relying on color alone, Cigala recommends fleets consult with their supplier and have a discussion about their actual requirements.
“What makes and models of equipment and engines do they have in the fleet? What is the OEM recommendation for those? What maintenance goals are they trying to establish?” he rhymed off, as questions a fleet and its coolant provider should be addressing. “There are definitely a bunch of different coolants out there on the market and you really have to align with your supplier to ensure you’re using compatible coolants. A lot of fleets just look at price. You get what you pay for. You need to understand what you’re getting.”
And you also need to understand how evolving engine technologies affect coolant requirements. For example, an increased use of aluminum to reduce engine weight has led some engine makers to advise against nitrite-containing coolants.
“A reaction can happen [between aluminum and nitrite] in certain circumstances and the nitrite can react with aluminum. When it reacts, [the nitrite] is used up and won’t be there to provide that corrosion protection,” explains Jordan. “Also, it will raise the pH and create ammonia so there’ll be an ammonia smell to the coolant if you’re having that nitrite/aluminum reaction. Most truck OEMs are moving away from nitrite coolants.”
Consolidate when possible
One of the biggest coolant-related risks fleets face is misfilling, or adding contaminated product, and that risk is heightened with each additional product that’s stored in the shop. Suppliers suggest consolidating coolants, to the extent possible.
“The first thing I look at is, are there opportunities for consolidation to make it easier on technicians?” says Cigala. “If you can get one product to fit everything, that’s really what you’d like to have. We always look at the opportunity to use one coolant across the board.”
Shell’s Jordan agrees that consolidating coolants is the easiest way to minimize risks. “The chances of topping off with the wrong coolant are increased if you have more than one coolant,” he reasons. “Generally, you can work with your coolant supplier and truck OEM to find one coolant to cover the needs of your whole fleet.”
But Troy Olmsted, Ontario sales manager with lubricant distributor Catalys, says consolidation must be done thoughtfully.
“It has to be done right,” he says. “A lot of work has to go into it. I’ve seen plenty of times where the wrong product got into the wrong application because they thought they were close enough.”
Inspect, inspect, inspect
“Coolant testing has to be in your maintenance program, there’s no way around it,” warns Cigala. This can consist of sending samples to a lab – much like an oil analysis program – or using test strips in the shop. Visual inspections are also important.
“Look at it for clarity. Make sure it’s not rust-colored and it doesn’t have an ammonia smell to it that tells you the pH is off the charts and you could start having corrosion inside the engine,” recommends Cigala, suggesting fleets inspect and test coolants at least twice a year, ideally before summer and winter.
Freeze points also need to be tested before the cold weather arrives. For optimal freeze point protection, a 50/50 water/glycol mix must be maintained, Jordan adds. Use test strips to confirm this ratio is maintained, especially before winter.
When using test strips, ensure they’re matched to the coolant that’s being tested, Jordan adds. “Most test strips are designed to work with specific chemistry.”
Label, label, label
In the shop, it’s important to accurately label drums, transfer containers, and anything else related to the coolant – maybe even the trucks themselves. Cigala says he’s seen instances where used coolant was emptied into improperly labeled drums.
“I’ve seen used coolant go back into engines,” he says. “You have to make sure everything is labeled correctly. Know that you’re using new coolant.”
Jordan says maintenance managers should even label the truck’s coolant reservoir itself, to give technicians a final warning before potentially adding the wrong formulation. This is also helpful for when drivers have to add coolant while on the road. Labeling the truck’s coolant reservoir is the last defense against a misfill.
Educate techs and drivers
Coolant leaks may first be noticed when the truck is on the road, and drivers should be trained on the appropriate steps to take before the truck returns to the shop. The ideal solution is to top off with the same coolant used by the fleet, so stowing an extra bottle in the truck’s storage compartment is better than having the driver add whatever was available at the truck stop.
Sometimes topping up with water will get the truck home to the shop, but Cigala says not any old tap water will do.
“Using deionized water or a good quality water when making adjustments or mixing the concentrate is key,” he says. “Some tap waters are hard and you can get scaling inside the engine, lose heat transfer, or scaling on the side of the radiator or the heater core. Those are all bad things. You have to make sure you use a really good quality water.”
When a driver tops up the coolant, it should be reported to maintenance, which should then test the chemistry using test strips to ensure it’s still in balance, Jordan adds.
If a truck blows a hose on the road, Cigala says the technician should drain the entire system and flush it with clean water before refilling with new coolant. And if the truck comes from the factory with an ELC capable of 300,000 miles, keep in mind it’ll only go 300,000 miles if top-ups are also of the same ELC, he points out. Even an ELC with a million-mile life will experience water evaporation over time, so it needs to be inspected and tested on occasion, Jordan adds. Even the longest-life coolants in the market need attention.