The more careful you are with coolants, the more life – and profit – you get out of your engine.
The top concerns for engine upkeep tend to be oil and filter changes. But the far greater challenge of maintaining proper coolant protection also is vital to an engine’s life.
Other than time and heavy use, the two main causes of coolant deterioration are chemical contamination and using the wrong mixture when topping off.
Chemical contamination results from running a diesel engine with wet cylinder liners, which causes tiny amounts of impurities to seep into the coolant through the seals, which don’t seal perfectly even when new. Such seepage creates an unwanted “science experiment” inside the coolant system, says Garrett Funk, western regional manager for Penray Cos.
The biggest concern in coolant maintenance, however, is deciding which antifreeze and how much water to use in replacing leakage.
The largest single ingredient in coolant is ethylene glycol, which, when equally mixed with water, lowers the coolant’s freezing point to minus 34 degrees Fahrenheit.
Failure to use coolant can cause your engine to freeze during extreme cold, wreaking havoc on your engine. But using too much coolant and not enough water can reduce the ability of the coolant to remove heat from your engine, which also causes problems. This balancing act is one of your biggest concerns.
Most owner-operators know they need to constantly look for leaks, but one of the easiest ways to keep your system full is to check the radiator cap. This easy step often is overlooked, Funk says.
“With a bad cap, you’ll lose antifreeze by evaporation,” he says. “Pressure test the cap periodically. Do this at least once a year. Every couple of months would be ideal.” To do this, you can use an inexpensive tool that consists of an air pump and pressure gauge.
Funk also suggests inspecting hoses for brittleness and hose clamps for tightness. If the clamps need frequent tightening, switch to spring-loaded constant torque clamps.
Coolants come in two camps: conventional antifreeze and extended life coolant.
Conventional antifreeze uses nitrites and borate inhibitors to protect metals. While this works just fine, the inhibitors can break down in hot, corrosive environments. For that reason, conventional antifreeze requires periodic replacement of the inhibitors with supplemental coolant additives, or SCAs.
The newer product is extended life coolant, developed by Texaco but now widely produced. ELCs use organic acids called carboxylates to protect the metal surfaces. Carboxylates are more stable than SCAs and can last longer with the addition of a small bottler of extender about halfway through their life.
All major oil companies make ELCs. Shell’s Rotella includes a conversion kit allowing you to convert to ELC without draining the entire system, says Jim Roberts, Shell technical service specialist. Other ELCs include Final Charge Global from Old World Industries and Fleetguard’s hybrid ELC, called ES Compleat. Traditional ELC goes to 600,000 miles with an extender at 300,000.
Using SCAs can be challenging because their depletion level varies depending on how the truck is used. Their levels must be regularly tested and adjusted for conditions. Also, SCAs in excessive amounts can block heat flow or form grit that can damage a water pump seal.
When ELCs were introduced in 1994, traditional coolant manufacturers countered with their own new products. Penray led with its Need-Release coolant filter, designed to eliminate much of the testing for protection level and all the dosing with SCAs. This device supplies SCAs through membranes that act like a chemical screen door, letting some materials through while holding other stuff in. They also control how fast the stuff moves through.
“The Need-Release filter releases the SCAs according to the corrosion and acidity in the coolant to maintain 1,200 parts per million of nitrites,” says Penray’s Funk.
The filter is marketed under several brand names, including Penray Need-Release and Detroit Diesel Power Cool.
Several other manufacturers have sophisticated systems for controlling the speed at which SCAs dissolve and at least partially regulating their levels.
Filters remove particles that have dropped out of the coolant solution to form grit, which is one of the biggest reasons for traditional coolant change intervals of 240,000 miles.
Products such as the Need-Release filter must be used only in combination with antifreeze that already contains the proper dose of SCAs. Look for this designation on the antifreeze label – TMC RP-329 Type A fully formulated coolant.
It refers to a recommended practice (“RP”) of TMC, the Technology and Maintenance Council of the American Trucking Associations. This compatibility is required because the filter is designed to replace SCAs as they are depleted, but not to provide the initial charge.
Heavy-truck coolant also must meet the ASTM (American Society of Testing and Materials) 4985 standard, which guarantees that it is low in silicates, which are not approved for use in trucks in high concentrations.
Minerals commonly found in tap water can keep the SCAs from dissolving, resulting in failed protection as well as grit in the coolant. Even with extended life coolants, pure water is needed to protect against scale and blocked system protection. Consequently, any water added to the coolant system must meet the engine maker’s standards.
So it’s best to use a 50/50 pre-mix, which guarantees proper proportions and water that meets purity standards. But you can use tap water if the water provider’s water quality report meets the engine manufacturer’s standards for impurities.
When you install ELC, you must remove the water filter unless it’s one that has a “blank charge,” meaning it contains no SCAs. Caterpillar recommends removing the filter, no matter which type, so nobody will install the wrong type.
Conventional coolant added to an ELC system won’t cause any damage unless its content level rises to 25 percent. At that point the ELC’s protection will be compromised, says Carmen Ulabarro, of Chevron’s coolant division. If that occurs, you’ll need to flush and refill with ELC or convert to conventional, she adds.
If only ELC has been added, you’ll need only to “check the color at every PM,” Ulabarro says. Once the engine is cooled, remove the pressure cap from the radiator and overflow tank, or the pressurized overflow tank. The coolant should be “dark red and clear, with no sign of oil,” she says.
Test it with a temperature-calibrated refractometer, a device you should be able to purchase from any large-tool vendor. The level of protection should be between minus 12 and minus 62 degrees Fahrenheit, equivalent to 40 percent to 60 percent antifreeze.
“If the color looks good, and you’re sure to top off only with ELC, I would not test it further,” Ulabarro says.
Funk suggests more testing with Penray’s system – even though its Need-Release filter, by requiring only fully formulated coolant, largely eliminates worries about nitrite levels and SCA concentration. Still, if the wrong coolant is added, the level of SCAs could temporarily drop, so Funk suggests testing at your normal PM interval.
“Penray has new TS 200 test strips that are universal and can be used with the ELC coolant as well as fully formulated or conventional without SCAs,” Funk says. “The strips have three pads, the top one for the percent of glycol, the middle pad for testing conventional coolants for nitrite levels, and the bottom pad to give a pass or fail for extended life coolant.”
Need-Release is ideal for use on older trucks, which are more likely to experience leakage. Even if a coolant system gets contaminated, the addition of SCAs will bring it back to life.
The Need-Release filter must be changed every 15 months or 15,000 miles, whichever comes first, Funk says.
Especially with EGR engines and in applications where the engine works very hard in hot weather, ELC may have another advantage: better heat transfer. “The newest engines may run up to 35 degrees Fahrenheit hotter than older models,” Ulabarro says. “With ELC, you get 10 percent to 12 percent better heat transfer. There are no silicates to interfere with the flow of heat.”
If you manage to keep your cooling system leakage to a minimum and can add only ELC, it’s likely to be the most cost-effective and hassle-free protection system.
ADDING UP THE COSTS
Figuring the cost of extended life coolant is a matter of putting a pencil to paper for your particular situation. You also can try the calculator Final Charge provides on its website, to calculate potential savings from using ELC.
Estimates of ELC cost are $8 to $10 per gallon, and $6 to $8 for fully formulated. A need-release filter costs about $50.
Obviously, if you experience chronic leakage, the cost of coolant alone might be slightly lower with fully formulated than with ELC.
If maintaining your antifreeze takes too much time away from hauling, that’s a cost factor to consider.
This comparison is based on the costs incurred for 60 gallons over 600,000 miles and the allowable hours of the standard change interval.
Price per gallon $8.50
Antifreeze cost $510
No. filters 4
Price per filter $50
Filter cost $200
Test kits (50 pk) 1
Price per kit $20
Test kit cost $20
Price per gallon $10.99
Antifreeze cost $659.40
Extender bottle 1
Price per bottle $12.99
Extender costs $12.99
No. test kits 5
Price per kit $5.99
Test kit costs $29.95
‘EXTENDED’ IS A LONG TIME
Standard coolant is good for about 150,000 to 240,000 miles. When using need-release filters and fully formulated antifreeze, the coolant’s standard life is 600,000 miles. That can be extended to overhaul, up to 900,000 to 1 million miles, provided you verify the coolant’s condition with a good lab test.
When do you have to flush and refill? Standard extended life coolant is good for 300,000 to 600,000 miles, normally the latter, with the addition of a bottle of extender at 300,000 to 400,000 miles, says Josh Russell, brand manager at Old World Industries, maker of Final Charge Global. Check with your engine and vehicle manufacturer for the approved service interval.
The life of ELC may be further extended through the use of Caterpillar SOS Level 2 Coolant Analysis, says Rae Baum, a Caterpillar engineer.
The latest version from Chevron will go to 1 million miles with the addition of an extender at 500,000 miles, and last 750,000 miles even without the extender. In high idle or vocational applications, make sure you’re not exceeding the allowable number of engine hours.
You must add ELC only whenever you top off, though as much as 25 percent of traditional coolant can go in before you have to flush the system and start over.