Michael Mathe
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It's Important to Adjust Drain Intervals According to Normal and Severe Service Recommendations

Driving habits and the work demanded from vehicles vary greatly. During the week, my old Suburban gets me to work and back over my 24-mile commute; on the weekend, when I'm lucky, I drive 180 miles over to Eagle River, Wis. to enjoy some fishing. Occasionally I drive down to Madison, Wis. to visit my daughter at college, which puts me on the road for a minimum of 10 hours in two days. So how severe are my driving conditions? A daily commute, some light towing and some highway driving seem harmless to me. When I actually break down the miles or hours I put on the Suburban, 80 percent of the miles I log are from workweek commuting; I don't get out fishing more than five or six times a year. With drain interval recommendations dependent on classification of "normal" or "severe" service, determining when to change oil can be more difficult than it seems.

Normal service is defined by AMSOIL INC. in the Product Recommendation and Drain Interval Guide (G1490) as, "Personal vehicles frequently traveling greater than 10 miles at a time and not operating under severe service." AMSOIL INC. defines severe service in gasoline applications as, "Turbo/supercharged engines, commercial or fleet vehicles, excessive engine idling, use of AMSOIL engine oil in vehicles with more than 100,000 miles without prior regular use of AMSOIL engine oil, daily short-trip driving less than 10 miles (16km), frequent towing, plowing, hauling or dusty-condition driving."

Severe service for diesel engine applications is defined as "extensive engine idling, daily short-trip driving less than 10 miles (16km) or frequent dusty-condition driving." The list of driving habits denoting severe service in diesel applications is shorter because diesel engines are built for working conditions and diesel combustion by-products have less of an effect on oil than gasoline combustion by-products.

Stop-and-go driving and excessive idling are especially hazardous to engine operation, so it is vital for vehicles like taxi cabs to pay attention to engine hours in addition to miles on engine oil. As indicated by the data displayed in the table above, an engine with low miles but high hours may still be operating under severe conditions.

A vehicle traveling primarily on-highway accumulates 15,000 miles in only 313 hours. A taxi traveling the same distance accumulates over 1,000 hours on the oil. Because a taxi drives at very low speeds and idles excessively, the hours on the engine oil can be five times greater than that of a vehicle moving at high speeds for extended periods of time. A vehicle in stop-and-go traffic takes over 700 hours to accumulate 15,000 miles. Engine hours are an important factor to consider when discussing the severity of service.

During short trips (less than 10 miles), a vehicle's engine oil spends a relatively small amount of time at actual operating temperature; this is especially true in colder climates. Frequent starts and excessive idling cause fuel to build up in the oil sump. Fuel dilution causes a decrease in motor oil viscosity, which can create abnormal wear by reducing the protective barrier of oil. Water also accumulates in engines that don't spend enough time at operating temperature. Water can initiate breakdown of the oil and result in a sludgy mess if sufficient quantities are present long enough.

Frequent towing puts a different strain on engine oil. When an engine is operating under heavy load, oil temperatures can increase significantly, which promotes oxidation. As temperatures increase, engine oil reacts with air, and oxygen molecules attach to the base oil chain making it heavier and thicker. This reaction causes decreased oil pump-ability. Excessive oxidation causes sludge and other deposits accumulating in the engine. This is one of the primary reasons for reduced drain intervals under this severe-service condition in gasoline applications.

AMSOIL synthetic motor oils - Signature Series in particular - are designed for extended drain intervals beyond OEM recommendations. The example based on my own driving habits confirms that my once-per-year oil change with Signature Series 5W-30 Synthetic Motor Oil is perfectly acceptable. I commute 24 miles a day, haul the boat five or six times a year and make a couple of long trips to see my daughter; I am not over-stressing my engine. It's important to examine your driving habits and conditions to ensure your vehicle is receiving the best protection possible. Published, AMSOIL Magazine 03/13. LLC is a large nationwide Dealer of AMSOIL Synthetic Lubricants and is now expanding into your area and surrounding states. If you have a business or are an individual with several vehicles, AMSOIL has several options available that may allow you to Purchase AMSOIL Products at Wholesale Prices. We can show you how to save money and extend equipment life with AMSOIL Synthetic Motor Oils, Lubricants, Filters and Fuel Additives. Please visit the AMSOIL Online Store for more information about AMSOIL Products.

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