When heavy diesel emissions control systems were first introduced (could it be only five years ago?), just about everyone in the trucking industry was concerned.
Fleets were asking if the systems would even work, and if they did, what problems and additional expenses would they bring? Truck manufacturers might know these engines were going to generate additional heat and were very concerned about the problems it would cause. Even cooling system experts were worried. “The primary concern before the introduction of EGR systems in 2002 was whether the coolant would survive the spiking of temperatures it would experience where the exhaust entered the pre-cooler,” says Darrell Hicks, a recognized member of the Technology and Maintenance Council and owner of Darrell Hicks Enterprises, an experienced cooling system supplier to the trucking industry.
In a similar way, Donaldson Co.’s Matt Stein describes the results of engine design changes made in response to emissions regulations by saying, “The increased use of EGR, tighter engine packaging and other engine strategy changes have combined to create an environment where engines sometimes operate at higher temperatures. This makes it more important than ever to make sure coolant systems are functioning properly.”
Stein’s colleague, Keith Bechtum, the company’s engine liquid product specialist, agrees, saying, “Because engines are running hotter, it’s more important to make sure the cooling system is properly maintained, because you’re asking the system to do more, and you’re depleting the additives faster.”
It turns out that the concerns were well-founded but quite properly ad-dressed by cooling system design engineers. Hicks says, “As long as the coolant continued to flow, had the appropriate antifreeze/water ratio and the correct pressure cap; the concerns were not realized. It truly became a ‘non-event.’”
Properly spec’ed cooling system components also contributed to this “non-event.” Gates Corp. engineers, for example, discovered what you can’t see can hurt you. During long-term field tests, they identified the primary cause of coolant hose failure as an electrochemical attack on the rubber inside the hose. This can result in very small cracks in the hose tube allowing the coolant to attack and weaken the hose reinforcement. Accelerated by heat and flexing, the hose can develop a pinhole leak or actually rupture. To solve the problem, Gates developed an electrochemical-resistant hose using a ethylene propylene (EPDM) formulation inside and a special wrapped reinforcement. In addition to chemical resistance, EPDM hose offers superior bonding to metal fittings compared to either standard rubber or silicone hoses that helps to prevent coolant leaks.
However, if continuous service over ...