After 409,000 miles without an oil change, the AMSOIL-protected Mack engine in this 1990 truck was as wear-free as an engine in comparable service treated to TWENTY TIMES the oil changes.

Colonial Heights, Virginia --"I didn't see any surprises in there at all," said owner/operator Haywood Gray of his 1990 Mack E7-400 engine at teardown after Gray had run the engine 409,000 miles without once changing the oil.

Gray used AMSOIL Synthetic 15W-40 Heavy Duty Diesel and Marine Oil, a AMSOIL By-Pass Filter and periodic oil analysis to achieve his impressive drain interval.

When the E7-400 was torn down by the local Mack dealership and its parts were examined by a certified independent engine rater, it showed only light to moderate wear throughout.

In fact, according to the engine rater, the parts could have been put right back in the engine.  "I see no reason why the engine couldn't run on," he said.