Introduced back in the 1980s to save on maintenance costs and provide better protection than conventional coolants, heavy-duty extended life coolants (ELC) can last between 400,000 and 600,000 miles with the use of a one-time extender.
In theory, it would seem only a matter of time before ELCs become the standard, but sometimes what looks great on paper is not always as effective in the real world. Industry experts say while these coolants can be extremely effective and save significant money, they are not necessarily right for every fleet.
For fleets with good maintenance programs, ELC has many advantages, says Chevron direct channel marketing manager Carmen Ulabarro, but none more significant than reducing maintenance times on cooling systems.
"They don't have to add additives, they don't have to test it with test strips every three or four months, they don't have to keep supplemental coolant additives in their shops, and basically they can use one coolant for everything," she says. "Extended life coolants work better as far as heat transfer agents, because they lack some of the inhibitors that actually reduce heat transfer that are found in fully formulated coolants. An extended life coolant has no abrasives, so water pumps last longer. There's no plugging with extended life coolants; there's nothing in the coolant that would allow for plugging, you don't have to refortify them every four months or so."
One of the main problems coolants help prevent is pitting of cylinder liners, which can cause coolant to leak into the engine and shorten its life, but how that is accomplished depends on the additives used. Shell OEM Technical Manager Dan Arcy says in a conventional, or fully-formulated setup, the 50-50 glycol and water mix requires periodic additions of supplemental coolant additives (SCA) to protect the liners; generally every 15,000-25,000 miles, depending on what the technician finds.
"They're going to have to find out how much of that SCA is in there still, and top off and bring it back up to specifications," he says. "That's the big difference between them (and ELC), and that's where a lot of the reduced maintenance and reduced costs comes from--it's the ability to not have to add additional SCA."
With ELC, the only time you will need to add an extender is at 300,000-miles, Arcy says, which should bring the life of the coolant up to 600,000 miles. Less maintenance is only one of the potential advantages for ELCs, though.
"We see increased water pump life, cleaner radiators, because you don't see the SCAs plating out in there," Arcy says," And you get the better heat transfer, which, with a lot of newer engines running hotter, is a benefit."
MAKING THE SWITCH
Since many fleets are switching to ELCs, they are asking OEMs like Freightliner, PACCAR, Volvo/Mack and International to factory-fill new trucks with extended life coolants, Ulabarro says. For fleets that haven't yet, she says there are plenty of good reasons to give them a try.
"When you look at how temperatures are going up, you're looking at the 2010 engines, you're looking at trying to extend oil drain intervals, you're trying to improve fuel economy, and we know the biggest factor in fuel economy is really the driver," she says. "The higher, better, more technologically advanced fluids you have in your system, the better your fuel economy is going to be. If your coolant is working effectively and transferring heat effectively, your oil will be able to last longer. If your oil doesn't thicken, it will take less energy to start up your truck. All of these things are a circle, and you've got to get everything in there working correctly.
"When you're looking at (ELC), you need to think about the benefits it can give you outside of long-term, ‘How am I going to reduce my maintenance?" Ulabarro says. "There are other things in this whole equation that really add up as a benefit for extended life coolant that you may not be able to add a dollar sign to, because it's variables--depending on the truck, how it's run--but all those little things add up, and also the reduction in maintenance that you have to do with an extended life coolant, as far as parts."