Truck Parts and Service | Heavy Duty Trucking, Aftermarket, Service Info
Issue link: https://read.dmtmag.com/i/93351
Remanufacturing Update By Denise L. Rondini, Executive Editor drondini@randallreilly.com talks about remanufactured charge-air coolers. TPS: What is involved in the re- manufacturing of charge-air coolers? Miller: To understand the remanu- facturing of a charge-air cooler (CAC) one needs a defi nition. Th e trade associa- tion that tends to oversee the service of CAC product is NARSA, Th e Internation- al Heat Transfer Association. Charge-air coolers are either new or remanufactured. However, truck owners need to understand that by NARSA's defi nition a cooler can be termed as new when the "tanks," "horns," or most correctly, "manifolds" are separated from the heat exchanger section, "core" or "brick," and a new heat exchanger section is re-welded to those manifolds. However, those own- ing heavy-duty vehicles may choose to term that remanufactured. So nomencla- ture can be confusing. Th e charge-air cooler is an interesting product because its very nature presents an engineering dichotomy. It needs thin cross-sectional areas for maximum heat rejection, yet needs to be a robust design to resist failure from thermal fatigue that sets in aſt er hours of expanding and con- tracting from the heating up and cooling down due to varying road load situations. While technically the CAC has no moving parts — versus the turbocharger that feeds it boosted hot air — it com- monly cannot last as long in-service as that turbocharger feeding it. While the turbocharger can rotate be- yond 100,000 RPM, the cooler can crack and leak the turbo's boosted air causing 18 excessive smoke, and low-power com- plaints; and that happens very gradually as the thermal crack grows over time. TPS: Are there any new develop- ments in charge-air coolers remanufac- turing? Miller: Th ere really are not any new developments in CAC remanufacturing, but there are elements of construction that heavy-duty parts marketers and truck fl eets need to be aware of. Th e most popular design used for original equipment/fi rst-fi t vehicle production is known as the tube and fi n design. Th is design works well, and is the lowest cost method for new production. However, it will typically not last as long in service as other methods of cooler construction. Th e tube and fi n design employs the use of an assembly component called a header plate. Th e header plate is the com- ponent part in the tube and fi n design where most thermal fatigue-type failures occur. In fact, a Society of Automotive Engineers study revealed that approxi- TRUCK PARTS & SERVICE | October 2012 mately 95 percent of all CAC failures were within the header plate. Remanufactured coolers made from replaced and re-welded heat exchanger center sections commonly use tube and fi n type replacements. Still, there are other designs that employ the use of fl ex- ible grommets, or gaskets to seal the seam between the heat exchanger section and the air manifolds. Some of those designs still are sold, some are not. Th e bar and plate type of construction completely does away with the use of the header plate entirely, and so with it the majority of causes for failure. While a re-welded center section may be an acceptable method for remanufac- turing, the choice of whose heat exchang- er center section is used also can correlate directly to the cooler's effi ciency and its durability. Once assembled, it's extremely dif- fi cult for the truck parts professional or fl eet to determine the origin as to whether it is an OEM quality component not. Th e bar and plate form of construc- A Look At Charge-Air Coolers I n this installment of the Reman Up- date, Jay Miller, vice president of Av- Tekk, a division of Diesel USA Group,