In October 2012, AMSOIL told the story of Jerry Pruett’s one-million-mile-plus Kenworth.* The Woodhull, Ill., native installed AMSOIL synthetic lubricants when he bought the truck new in 1999. After reaching 1.6 million miles on the original transmission and differentials and 1.1 million miles on the factory-rebuilt engine in 2012, Pruett has since eclipsed 2 million miles and shows no signs of slowing down.
The truck, which Pruett uses to haul freight predominantly around the Midwest, has required little maintenance since 2012. In November of that year, Pruett did finally need to replace the fuel injectors. “The spray pattern on the pistons was still good,” he said. “The springs must have weakened over time. Other than that, there was nothing wrong with them.” All six injectors lasted 1.1 million miles. Injectors typically require replacement prior to 500,000 miles, says Pruett. Pruett attributes their longevity to continuous use of AMSOIL Diesel Injector Clean.
Since he was replacing the head gasket anyway, Pruett elected to replace the entire cylinder head to expedite replacement of the injector cups. Other than the head and a new water pump, the engine has required no work in the intervening years. “It keeps humming along,” Pruett said.
The turbocharger is still original. Pruett runs AMSOIL 15W-40 Synthetic Heavy Duty Diesel and Marine Oil. He also uses an AMSOIL DUAL-GARD® Oil Filtration System and changes oil approximately every 100,000 miles, which saves him significant money.
The differentials and transmission are still original after 2 million miles. Pruett uses AMSOIL SEVERE GEAR® SAE 190 Synthetic Gear Lube in the differentials, although AMSOIL primarily recommends 75W-90 Long Life Synthetic Gear Lube in over-the-road applications. “A little bit thicker oil couldn’t hurt with the high miles,” he said. He uses AMSOIL DOMINATOR® SAE 60 Synthetic Racing Oil in the transmission, although AMSOIL primarily recommends SAE 50 Long-Life Synthetic Transmission Oil. “It’s probably been in there 600,000 miles,” he said.
Pruett has learned firsthand how good AMSOIL synthetic diesel oil protects in severe conditions. He was changing his by-pass filter last winter, and it was cold and he was in a hurry. He accidently left the O-ring behind on the filter mount, which prevented the new filter from seating properly. “About four miles down the road, the oil-pressure light came on,” he said. “Sure enough, I found an oily mess by the bypass filter.” Fortunately, Pruett always carries four gallons of oil with him. The truck required the entire four gallons to register oil on the dipstick. His engine has suffered no ill effects, however.
“With any other oil, I’d probably be overhauling the truck,” Pruett said.
Pruett uses his truck and his AMSOIL experience as a rolling advertisement for his AMSOIL Dealership. The people with whom he shares his story still have a tough time believing it. “They shake their heads in disbelief,” Pruett said. “They think, ‘No way can you have that many miles on a truck.’ And I only change oil once a year.”
Now 64 years old, Pruett doubts he’ll be working long enough to see 3 million miles. He hopes to spend more time pursuing his AMSOIL Dealership – and he has a great testimonial for everyone he meets along the way. “I’m not only an AMSOIL Dealer, I’m an AMSOIL user and abuser,” Pruett said. “I won’t use anything else.”