2 Million Miles On AMSOIL


October 2012 – After 1.6 million miles on the original drivetrain and 1.1 million on the factory-rebuilt engine, Jerry Pruett and his AMSOIL-Lubed Kenworth show no signs of retiring.


When AMSOIL Dealer Jerry Pruett of Woodhull, III. purchased his new 1999 Kenworth over-the-road truck in December 1998, he thought it might run forever if he installed AMSOIL synthetic lubricants. Now with more than 1.6 million miles on the drivetrain and over 1.1 million on the factory-rebuilt engine, “forever” still remains in sight.

The mileage is even more impressive considering how little work the truck has required. The Detroit Diesel Reliabilt® engine still has virtually all of its original components, including the turbo and fuel injectors. The truck accumulates 2,300- 3,000 miles a week hauling loads averaging 27,000-35,000 pounds, with some up to 80,000.

The reliability of the drivetrain is also notable. Though the clutch has been replaced a couple times, the transmission hasn’t been touched. “I’ve done nothing to the transmission. All the gears in it are at 1.6 million miles,” said Pruett. The differential gears are also original to the truck.

Pruett runs SAE 60 Super Heavy Weight Synthetic Racing Oil (AHR) in the transmission. He uses Severe Gear” SAE 190 Synthetic Gear Lube (SRN) in the differentials, although AMSOIL primarily recommends 75W-90 Long Life Synthetic Gear Lube (FGR) in over-the-road applications. “A little bit thicker oil couldn’t hurt with the high miles,” said Pruett.

AMSOIL Helps Increase Life of Defective Engine
The truck was originally equipped with a Detroit Diesel engine that, unknown to Pruett, contained a manufacturing defect known to cause catastrophic failure early in the engine’s service life. Pruett initially installed Shell Rotella during the break-in period. “I wanted the rings to seat prior to switching to AMSOIL,” he said. At about 140,000 miles, he installed Series 3000 Synthetic Heavy Duty Diesel Oil (HDD).

With 506,000 miles on the engine, the number three piston failed. “In talking with the mechanics, I found out there was a defect on these engines, and some blew around 300,000 to 375,000 miles,” said Pruett. “In one instance, a rod came through the engine and punctured the computer. I felt my engine lasted as long as it did because of AMSOIL.” When the mechanics removed the cylinder heads, the original hone marks were still visible on the cylinder walls. “The mechanic said the engine was not wearing out; the oil was doing a great job. Had it not been for the piston failure, it could have run forever.”

Detroit Diesel Reliabilt Engine
Despite the engine warranty having expired 6,000 miles earlier, Pruett presented his case to Detroit Diesel. “I felt Detroit Diesel was taking advantage of me. Other guys using any old oil were receiving warranty coverage because their engines failed sooner. I told them I was using the best oil in the world and, because of that, the engine lasted longer,” said Pruett. “To have that engine last past the warranty was a surprise to them, I think.” Detroit Diesel agreed to provide Pruett a factory-overhauled engine at cost, in addition to $4,500 for installation.

The factory-rebuilt engine has since powered the truck for 1.1 million miles, requiring virtually no repairs. “I haven’t even pulled the cylinder head off this thing,” Pruett said. “I didn’t replace the water pump until accumulating over 900,000 miles. Usually a water pump lasts 350,000 miles on a good day.” As with the previous engine, Pruett installed Shell Rotella during the break-in period prior to switching to Series 3000 Synthetic Heavy Duty Diesel Oil.

The lone repair required was replacement of the camshaft at about 100,000 miles, barely out of the break-in period when still using Shell Rotella. Pruett believes the camshaft was original to the engine and not replaced when the engine was factory re-built by Detroit Diesel.

“The truck really kind of scares me; it runs so good.”
– Jerry Pruett

With close to 800,000 miles on the engine, Pruett switched from Series 3000 Synthetic Heavy Duty Diesel Oil to higher viscosity 15W-40 Synthetic Heavy Duty Diesel and Marine Oil (AME) to guard against excess oil consumption common as engines age.

During a routine 31-point inspection completed when Pruett had a faulty sensor replaced, the mechanic remarked how nice the turbo looked. “They thought it had only been in for a couple months,” said Pruett. “It was 12 years old.” Pruett credits the Donaldson Endurance Heavy-Duty Air Filter for the turbo’s longevity. “I was sold on the air filter from day one,” he said. “Throttle response was quicker, it
boosted the horsepower a little bit and turbo noise decreased.”

100,000-mile Oil Changes
Pruett also uses the AMSOIL DUAL- GARD® By-Pass Oil Filtration System fitted with two EaBP110 By-Pass Oil Filters. Regular oil analysis continually indicated the oil was suitable for continued use, allowing Pruett to establish an oil change interval of once per year, or about every 100,000 miles, based on historical data. The EaBP110 By-Pass Oil Filters are changed twice a year, or about every 50,000 miles. Practicing extended drain intervals saves a considerable amount of money each year compared to using conventional oil and standard drain intervals. “Some guys are spending up to $1,200 a year on oil changes when they could be spending half that with AMSOIL,” said Pruett “They’re throwing their money away.”

Excellent Fuel Economy
Additional savings are realized each time Pruett fills his diesel tanks. “The truck really kind of scares me; it runs so good. I’m still getting about 7 mpg,” said Pruett During a run from Indianapolis, Ind. to St Louis, Mo., the truck achieved 9.7 mpg. “The truck is capable of that mileage if I can just keep my foot out of it,” said Pruett He has used AMSOIL Diesel Concentrate (ADF) since day one, which not only helps fuel economy but, according to Pruett, has contributed to the fuel injectors lasting as long as they have. He also keeps AMSOIL Cold Flow Improver (ACF) on hand and uses it when conditions dictate.

No End in Sight
Pruett’s truck serves as a rolling billboard for AMSOIL; it displays AMSOIL decals, along with the contact information for Pruett’s AMSOIL Dealership. He shares his AMSOIL story with truckers at every opportunity. Pruett turns 62 in January and has thought about retiring, but, unfortunately for him, his truck has not “I really want to see how far this truck can go, so I keep on trucking away.”

Jerry Pruett’s Truck At A Glance

  • Detroit Diesel Reliabilt Engine
  • 1,151,904 Miles on Engine
  • 1,657,904 Miles on Drivetrain
  • AMSOIL 15W-40 Synthetic Heavy Duty Diesel and Marine Oil (AME)
  • AMSOIL By-Pass Filtration System wI EaBP110 By- Pass Filter
  • Once-per-year (approx. every 100k) oil change interval
  • Aside from camshaft, all components original to engine, including turbo and fuel injectors
  • Original transmission and differential gears

UPDATE: June 2015 – 2 Million Miles On AMSOIL And Still Going Strong!

In October 2012, AMSOIL Magazine told the story of Jerry Pruett’s one-million-mile-plus Kenworth. The Woodhill, 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 stili 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 (ADF).

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 (AME).  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 (SRN) in the differentials, although AMSOIL primarily recommends 75W-90 Long Life Synthetic Gear Lube (FGR) 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 (FTF). “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 accidentally 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 by-pass 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.”

How Far Is 2 Million Miles?

  • 720 Times From New York To Los Angeles
  • 80 Times Around The World, At The Equator
  • 4 Times To The Moon And Back

The Question Isn’t “How Much Does AMSOIL Cost?” It’s “How Much MORE Is It Costing You To Use Something Else?

For Information On AMSOIL Products, Drop Us A Note Or Call Us At (508) 238-6606.

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