The Spinner II bypass filter uses centrifugal force to fling particles to a wall that can be removed and cleaned.
T.F. Hudgins, Inc.
Gary Frisbe runs a 550-hp Caterpillar in over-the-road operations. “My Cat has 750,000 miles on it,” he says. “I do my oil changes at 12,000 miles and use the standard filter that came on the truck. I have not done an overhaul yet and don’t need one.”
Like Frisbe, many owner-operators stick to the filters that come standard with their trucks and change oil frequently. While that may be sufficient for some owner-operators, sometimes an inadequate or unmonitored filtration system can result in engine problems. To make the most of oil filtration – that is, to increase its benefit while containing costs – it helps to know what choices you have regarding a vehicle system that is largely hidden and seldom considered. It’s also good to practice routine oil analysis to make sure your filtration system is doing the job you expect it to do.
In addition to using a standard, full-flow filter, you have the option of adding a bypass (also known as part-flow) filter that siphons off part of the oil flow to remove smaller particles.
Some products combine a full-flow and bypass filter in one container. Stand-alone bypass filters are mounted between two hoses, one coming from an engine oil galley plug and a return hose going to the pan. Herman Miller, fleet equipment manager for Shopko Stores, warns that all bypass filters are not the same when it comes to installation. Some are gravity-flow; others are pressurized, and the type makes a difference in the placement of the hoses and the canister. Installation should be done only by a qualified mechanic. If your engine is still under warranty, consult with your dealer before investing in a bypass filter.
Full-flow filters trap the larger particles. If your full-flow filter gets clogged, a valve opens to relieve the pressure and lets unfiltered oil and debris flow through the engine. That limitation creates a need for bypass filters, but bypass filters also have other functions.
“Full-flow filters scavenge particles between 20 and 30 microns, while part-flow filters remove 85 to 90 percent of particles between 5 and 20 microns,” says John Clevenger, product manager at Fleetguard. Bypass
filters pull in only about 10 percent of the oil – between 2 and 3 gallons per minute – at a time and pass it through to the sump. They are capable of holding onto particles as small as 2 microns, which is the smallest size that can be accurately measured. Most bypass systems clean all an engine’s oil about five times per hour.
Acids, metals, water, soot and other solids contaminate oil and cause engine wear. As contamination levels rise, the additives in oil – not the base oil – become depleted and break down. This contamination restricts the ability of additives to reduce deposits and to hold solids in suspension. Sludge, which accounts for about 80 percent of oil contamination, is the most significant cause of engine wear, Clevenger says. But you can’t rely on your dipstick to tell you what’s going on in the crankcase. Within half an hour of running new oil, it will turn dark. The only real protection you have for your engine is filtration.
If you run heavy loads (producing more soot, acids and metal wear), north to south (causing water to condense due to drastic temperature changes), or in harsh or dusty conditions, consider using the more expensive synthetic media filters. They are designed to catch smaller particles.