Coolant Tips
Cooling systems have been called the Rodney Dangerfield of truck engine maintenance — they don't get no respect. It's tempting to cut corners on maintenance and save a buck or two, but doing that may cost you a lot more in repairs down the road.
"While maintenance can cut into profits in the short run, following the manufacturer's recommended maintenance requirements saves money in the long run," says Scott Hinkle, Mack reliability engineer. "Poor maintenance eventually results in higher overall costs."
How high? How about $10,000 to replace pitted liners because your worn-out coolant didn't protect them from corrosion? That's what "Buz" Lannom, Peterbilt's Great Lakes regional service manager, says it can cost, especially if problems extend into the engine block.
Here are seven ways to save money, downtime and labor by taking a more careful approach to maintaining the cooling system.
1. Use extended-release filters
If you're not using organic-acid based extended life coolants (ELC), use fully formulated conventional ethylene glycol coolants with a controlled-delivery coolant filter that replenishes the corrosion inhibition chemistry as the coolant ages.
This greatly extends the life of the coolant compared to earlier practices. Most of these filters are designed to last a year or more, so you save the cost of filters and maintenance labor costs compared to the traditional four to six filter changes a year.
These filters are marketed under names such as Penray Need-Release and Fleetguard ES.
Even if you are using an ELC, Dave Brisk, director of business development for coolant and chemicals at Fleetguard, recommends a filter. He says an extended-release filter specifically designed for use with these coolants can help make sure the chemical levels are where they should be, instead of waiting for the 300,000-mile extender that is part of the ELC package.
2. Keep the system full
The average road tractor, after its first year, will use 10 to 12 gallons of coolant a year, says Darrell Hicks, OEM liaison for Penray. With modern engines, it's even more vital that the cooling systems stay topped off regularly with the proper coolant.
"If the cooling system gets low with these new EGR engines, they have every chance of cooking the EGR unit," he says.
Peterbilt's Lannom points out that the 2002 emissions engines featuring exhaust gas recirculation run 10 to 15 degrees hotter than their predecessors. "The fluid level is really critical," he says. "If it gets too low, the cooling system can't deplete the heat out of the engine, so it has a tendency to cook the engine quicker than it would in the old-style engines."
Make sure drivers are topping off with the correct mixture of coolant and water, and the right coolant.
3. Price out new coolants
The initial price of extended-life organic-acid technology coolants is higher than that for regular coolant - in the range of twice as much. However, over the life of the product, proponents say, the actual cost can be less than that of conventional coolant.
Not only do ELCs last longer than conventional coolants (up to 600,000 miles), but unlike traditional coolants, which require regular additions of supplemental coolant additives, ELCs only require an inhibitor extender at 300,000 miles.
"Even though the fluid is less expensive, the overall time you spend maintaining your cooling system is reduced to almost nothing," says Carmen Ulabarro, coolant marketing specialist for ChevronTexaco Global Lubricants.
ELCs require no regular additive treatments, and, according to proponents, don't need coolant filters. This results in less downtime, less inventory and less labor. According to ChevronTexaco, ELC has also shown significant improvements in water pump life expectancy. In fact, ChevronTexaco says that after about six months, the initial ELC investment meets the ongoing conventional coolant investment, and that everything after that six-month mark is ELC savings.
"I think extended-life coolants are probably the future of cooling system maintenance," says Fleetguard's Brisk. "The extended-life products are really key to protecting the engine, especially as you get into exhaust gas recirculation technology and other things that increase heat and flow rates in the engine."
However, in order to realize the cost savings, Ulabarro cautions, you must be consistent. You have to be able to count on your technicians, your drivers and maintenance facilities on the road not to contaminate extended-life coolant with conventional coolant and negate all those cost savings.
4. Test coolant regularly
Whether you're using traditional coolants or the extended-life version, you can't just fill it and forget it, relying on the occasional top-off to keep things running right. This is probably the most common mistake truck owners make when it comes to taking care of cooling systems.
Either kind of coolant must be maintained at the proper ratio of coolant to water. The typical mix is 50/50, and coolant levels lower than 40% should be avoided. You can determine whether your system is protected by checking the freeze point with a refractometer.
"One of the biggest issues we see with any cooling system is to check the freeze point of the coolant," says Dan Arcy, product marketing manager with Shell Lubricants. "A lot of times, making sure that is taken care of takes care of a whole lot of issues."
The other thing that needs to be checked regularly is the level of chemicals in the coolant that protect the engine.
Traditional coolants must contain the right level of supplemental coolant additives, or SCAs, to protect against cavitation and the resulting liner pitting, among other things. Use coolant test strips at every oil change interval.
"A lot of fleets will watch their trucks perform for a year or so and decide to use an average mileage to determine when to add SCAs," Ulabarro says. "That's not really the program the coolant manufacturer is asking you to use. He's asking you to test each truck, because each truck performs differently."
If you don't test the coolant and just spin on a new SCA-charged filter or add another four ounces of liquid SCAs at predetermined mileage intervals, a common result is an overcharged system. Too-high concentrations of these chemicals can lead to plugging, increased deposits, and things like solder bloom, where the solder is deteriorated by too much nitrite in the coolant. Levels that are too low don't protect the engine as they should.
Extended-life coolants don't need additional inhibitors until 300,000 miles in most applications - assuming what's running through your coolant system is still extended-life coolant. These coolants can be diluted or contaminated by improper top-offs on the road, whether with water or with traditional coolant or automotive coolant. There are kits available now to test extended-life coolant, and most experts recommend testing it at least every six months, and preferably at every oil change.
"The industry has really kind of misled some customers about extended-life coolants, into thinking they never have to maintain it," says Peterbilt's Lannom. He recommends checking the coolant every 50,000 miles, especially in over-the-road fleets where it's easy for drivers or sloppy technicians to top it off with water or with non-ELC antifreeze. "With my customers, that's where they really get into trouble."
Fleetguard's Brisk points out that if an oil cooler leak occurs during that 300,000 miles before you put in the extender, and you never check it, you could be running with damaging oil in the coolant for a long time. "You have to look at the coolant and check it periodically."
5. Inspect from end to end
A cooling system is more than coolant. Routinely check hoses and tubes for bulges, leaks, cracks, soft spots, brittleness or other damage. Check hose clamps to make sure they're tight and undamaged.
Inspect the fan clutch and fan blades for proper operation. Check drive belts for proper tension and wear. Adjust and replace belts as necessary. Inspect the radiator cap for a secure seal with the radiator and check the thermostat for proper operation. Make sure radiator shutters (if your truck is equipped with them) open and close at the correct temperatures.
Regularly clean the "sandwich" of the radiator, air conditioner and air to air cooler. "It's really easy to get a lot of debris between them, bugs and dirt, and you're not getting the cooling you need," says Penray's Hicks.
6. Pressure test regularly
Pressure test the cooling system regularly. This can reveal any leaks and catch problems while they're minor. Recommendations as to how often vary. Shell's Arcy recommends doing it once a year, while Peterbilt recommends testing it at every maintenance interval.
This is done using a special pressure testing device, Arcy explains.
"Basically you take the radiator cap off, put the pressure tester on, pump it up to the maximum pressure the system's supposed to hold, say 15 pounds, and watch the gauge. If there aren't any leaks in the system, the pressure will maintain. If there's a leak, pressure will drop. You could have a small leak someplace, and you could save yourself some money by fixing it now and not having to top off with as much coolant on the road. Sometimes fixing these leaks is nothing more than tightening down a hose clamp someplace."
7. Don't forget the radiator cap
Pressure testing also should be done to check the radiator cap. If the cap is opening up too soon or not opening soon enough, the cooling system won't operate properly. It may divert coolant to overflow prematurely, leaving you without enough coolant in the system.
It's also important when replacing a radiator cap to use one that will maintain the correct pressure. New Class 8 trucks typically have 14 to 16 pounds of cap pressure. For every pound of pressure, you get 3 degrees of protection from boil-over, says Penray's Hicks.
"If that vehicle calls for a 16-pound cap, don't put a 7-pound cap on," he says. "As warm as these engines are now, as warm as the coolant is, you need those extra 9 pounds - that's a 27-degree comfort zone."
On the other hand, if you put a higher-rated cap on, you're putting more pressure on the system than it's designed to take and could create leaks in the radiator.
"The wrong pressure can really hurt a system," says Peterbilt's Lannom, "especially if you get air into the system. It deteriorates the additives and nitrites in the coolant." He recommends checking the radiator cap every 50,000 miles.
Making things more difficult, Hicks notes, is that not all manufacturers put the pressure on the box - just a part number. "It's a great opportunity for trouble."
Sidebars
Coolant Filters: Boon or Bane
Quick-Connect Coolant Drains Make Maintenance a Snap
