After 409,000 miles without an oil change, the AMSOIL-protected Mack E7-400 engine in this truck was as wear free as an engine in comparable service treated to TWENTY TIMES the oil changes. |
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Colonial Heights, Virginia - "I didn't see any surprises in there at all. Based on my experience with AMSOIL Motor Oil, it came out the way we expected," said owner/operator Haywood Gray of his 1990 Mack E7-400 engine.
It came out in good shape, exactly what you’ld expect for a well-maintained engine with 630,000 miles. Yet the engine's oil had not been changed for 409,000 miles!"

Gray began using AMSOIL Synthetic Heavy-Duty Diesel and Marine 15W-40 Motor Oil (AME) in the E9-400 V-8 engine of his first truck, a 1984 Mack, after the engine accumulated 45,000 miles. For 280,000 miles, Gray changed his oil at 40,000- to 60,000-mile intervals though his oil analysis reports showed, without exception, that the oil was good for continued use. At 325,000 miles, Gray increased his oil drain intervals to 100,000 miles.
The engine was torn down at 600,000 miles when Gray decided to sell the truck. The cylinder liners, bearings, pistons, rings and oil pump, all treated to extended oil drain intervals with AMSOIL, were found to be in excellent condition.
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Gray continued using AMSOIL AME in the engine of his new truck, a 1990 Mack with a E-7-400 engine. With the new truck, instead of using 100,000 mile drain intervals, Gray began basing his oil drains on the findings of a used oil analysis program. He also installed an AMSOIL By-Pass Oil Filter.
After 630,000 miles total and 409,000 miles without an oil change, the E7-400 engine was torn down by the local Mack dealership in December 1996 and its parts were examined by an engine rater from a major oil additive manufacturer.
Findings -- The engine showed light to moderate wear throughout, just as an engine in similar service and lubricated with conventional oil changed at 15,000- to 20,000-mile intervals would show. In fact, according to the engine rater the parts he examined - cylinder liners, pistons, rings, bearings, valve train components - could have been put right back in the engine and would have continued to provide the good, dependable service they had provided all along - after 409,000 miles without an oil change!
Discussion -- Many factors enable AMSOIL to be safely used 20 times longer than petroleum oils may be used.
Stability -- AMSOIL Synthetic Heavy-Duty Diesel and Marine 15W-40 Motor Oil is far less prone to thermal and oxidative breakdown than are petroleum oils. Stability inhibits the formation of carbon deposits, varnish, sludge and acids, which helps the engine run clean and protected.
Neutralization ability -- While rapid TBN loss often renders conventional oils unfit for continued use, 12 Total Base Number (TBN) AMSOIL Synthetic Heavy-Duty Diesel and Marine 15W-40 Motor Oil offers lasting protection against engine corrosion.
Viscosity retention - Some conventional oils' viscosity slips out of specification within a few thousand miles of an oil change. AMSOIL Synthetic Heavy-Duty Diesel and Marine 15W-40 Motor Oil neither loses viscosity as shear-prone oils do, which promotes wear during high temperature operations, nor gains viscosity as oxidation-prone oils do, which promotes wear during startup and cold temperature operations.
Gray's successful use of AMSOIL synthetic motor oil in extended drain service is not unique. AMSOIL has conducted demonstrations with fleets all over North America.
In each instance AMSOIL has been proven safe and effective in extended drain use. In fact, these studies show that AMSOIL used in extended drain interval programs consistently delivers lower rates of engine wear than conventional oils used in conventional drain interval programs.
Southern over-the-road fleet -- AMSOIL was used in Cummins class 8 engines for 75,000-mile drain intervals; the fleet's normal drain intervals were 15,000 miles.
Upper midwest grocery fleet -- AMSOIL was used in Cummins NTC 350 engines for 74,000-mile drain intervals; normal drain intervals were 12,000 miles.
Northern grocery fleet -- AMSOIL was used in Detroil Diesel Series 60 engines for 79,000-mile drain intervals; normal drain intervals were 20,000 miles.
Midwestern trucking fleet -- AMSOIL was used in Detroit Diesel Series 60 engines for 60,000-mile drain intervals; normal drain intervals were 20,000 miles.
Northern tier over-the-road fleet -- In an ongoing demonstration, AMSOIL Series 3000 5W-30 is being used in a fleet of Cummins N-14 engines for extended drain service with oil drains based on the findings of used oil analysis. One change was performed at one year with 125,000 miles on the AMSOIL. The oil was recommended for continued use. Normal oil drains are done at 20,000 miles.
Oil analysis is a maintenance management tool that allows users to monitor equipment condition for maximum equipment life, maximum lubricant drain interval length and optimal downtime scheduling. Oil analysis saves users significant money by reducing equipment replacements and repairs, reducing the volume of lubricant purchased and destined for disposal an, most of all, by reducing downtime.
Oil analysis customers like Haywood Gray "trendline" their oil analyses. Trendlining involves comparing the results of previous oil analysis reports to those of the most recent report to establish trends in wear metals content, viscosity, acid content, acid neutralization ability and other characteristics as specified. Departures from established trends indicate a change in engine or lubricant condition and the information they provide may be used to correct abnormal conditions before they cause damage or failure.
For a detail discussion of Oil Analysis, click here.