Converting to extended-life coolant.(truck engines)

Today's new engine coolant technology can reduce your maintenance costs, but it's not just a matter of drain and fill.

In 1984, the Maintenance Council (TMC) of the American Trucking Associations, Alexandria, Va., formed the Tomorrow's Truck Task Force. This group took on the chore of consulting with truck and component builders to make sure that the equipment of the future would meet the needs of our industry.

The group put together several Society of Automotive Engineers (SAE) papers on the subject--the last one published in 1993. Since the beginning, the Task Force has asked manufacturers to make vehicles and components less reliant on periodic maintenance. Almost all systems on a truck got a mention, including the cooling system.

It seems that maintenance people are not fond of testing supplemental coolant additive (SCA) concentrations at each preventive maintenance interval. And they're even less fond of costly engine repairs that result from their failure to get the complicated chemical balance just right.

The industry has made great strides in many areas. Transmissions and differentials used to need fluid changes at 50,000 mile intervals. Today, with proper fluid selection, that number is 250,000 miles or more. And the engine makers are now comfortable with recommendations of 25,000 miles or more between oil changes.

At a 1993 SAE meeting, Chuck Blake of Detroit Diesel presented a manufacturer's response to the Tomorrow's Truck paper. He admitted that the cooling system was one area that engine makers were still struggling with. But since then, even the cooling system has become less reliant on maintenance.

Some of the coolant filters available today release additives only as needed. This means that they can keep the SCA concentration within acceptable levels for a longer time. Extended-life coolants (ELC) now available can go for 300,000 miles without service. At that point they require the addition of only one can of extender.