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ECHANIC CONNECTION By Gary Goms, commercial accounts editor
When Selling Hoses, Always Consult Cataloging For Recommendations hanks to compact engine compartments, air conditioning, turbocharging, and computercontrolled cooling fans, underhood operating temperatures have risen dramatically. To withstand these extreme temperatures, most modern coolant hoses are now made from ethylene propylene (EPDM rubber, which can endure operating temperatures ranging from -40 to +275 degrees F. Thanks to extremely crowded engine compartments, about 90 percent of all automotive hoses currently produced are curved or molded to fit specific applications of vehicles, including “branched” hoses with three or more molded outlets. Coolant hoses are also manufactured in universal-fit straight lengths that can withstand up to 100 psi working pressures
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encountered in many commercial applications. Industrial applications can also benefit from shorterlength hoses specifically designed to absorb vibration and to correct for connector misalignment. Last, remember that many commercial applications require straight and molded silicone coolant hose that is rated to withstand temperature differentials ranging from -70 to +350 degrees F, which can be encountered on some over-the-road vehicles. Hose Installation Tips As you’ve probably guessed, cooling hose removal and installation techniques also have changed. Since EPDM coolant hoses tend to bond with metal connections like heater core inlet/outlet tubes, it’s always better cut, rather than twist or pull an old hose from its connection. If the hose is to be re-used, the technician should use a hose pick, which slips under the hose to separate it from its connection. Since a petroleum-based grease or oil can be harmful to the cooling system, any new coolant hose should be installed by lubricating with fresh coolant and pushing or twisting it onto its connection. Remember, too, that the original equipment (OE) spring-type clamps currently used by most auto manufacturers are designed to apply a constant, even pressure to the hose. Most aftermarket coolant hose manufacturers have designed replacement clamps that Continued on page 54
Specially designed pliers make the job of removing modern coolant hose clamps much easier.
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November 2013 | Counterman