Post '02 Engines Cost More To Run
Three fleets share their experiences and costs with new engines. summary: costs are up; fuel mileage down.
Jim Winsor
Executive Editor
One of the highlights of the fall meeting of TMC (the Technology and Maintenance Council of ATA) was a program focusing on fleet experience and costs with low-emission post-'02 truck diesels. Three well-respected fleets, all known for their accurate record-keeping, shared their experiences with engines using EGR (exhaust gas recirculation) or Cat's ACERT two-stage turbocharging with variable valve timing and pulsed fuel injection.
Speakers included Duke Drinkard, vice president of maintenance for Southeastern Freight Lines, Columbia, S.C.; Mike Jeffress, vice president of maintenance, Maverick Transportation, Little Rock, Ark.; and Ken McKibben, senior vice president of field maintenance, Penske Truck Leasing, Reading, Pa.
Southeastern runs its day cab tractors over the road at night, with many of them used in P&D service during the day. Drinkard compared his experiences with a group of 147 '02-model tractors – each with 140,000 miles – with 120 tractors built in 2004, also at the 140,000-mile point.
He said for the first 50,000 miles, the '04 engines (mostly Cummins) had a 16.3 percent decrease in fuel mileage, although mpg improved later on. He attributed most of this improvement to engine break-in. After the first 50,000 miles, he said the loss "improved" to a decrease of 12.2 percent.
He showed figures with a differential of 487 gallons per month per tractor after 50,000 miles, adding "that was with 95-cent diesel fuel." In 2004, with $1.25/gallon fuel, there was a $5,200 fuel cost increase per tractor per year.
In comparing failed parts, Drinkard reported the following: 14 failed turbos in post-'02 engines versus none for earlier models; 24 water pumps versus two; 25 injectors versus 19; 44 exhaust flex pipe breakages versus 21; and 242 EGR valves versus none (because '02 engines had no EGR). Increased costs included $139,635 for rental tractors due to 1,753 days of tractors out for repairs.
Maverick's Mike Jeffress compared a group of "pre" low-emission engines with 500,000 miles average with "post" engines at 300,000 miles. He said fleet fuel economy averages were 6.45 mpg versus 6.312 mpg – not a large spread.
Jeffress focused on mechanical problems – most under-hood heat-related – which caused expensive downtime. Frequency (in order): fan hubs, alternators, leaking charge air coolers, fan clutch linings, and air compressor unloader valves. He said '04-model engines had improved mpg over the 2003 engines. Oil analysis showed increased contamination and he had to shorten oil drain intervals.
Penske's McKibben reported cost comparisons based on the Penske fleet of 65,000 tractors – 46 percent of them with EGR diesels. Sixty-two percent are Detroits, 23 percent Cummins, and 15 percent Cats. He said as a group, engine costs went up 1 cent per mile per engine in '03 after the introduction of low-emission diesels. For '04, the differential dropped to 6 mils per mile.
He said the '03 EGR engines had only a slight drop in mpg but a noticeable increase in internal soot, which got better in subsequent years. He did shorten oil and filter change intervals. As with the other fleets, EGR valve failures (31 percent in '03) and turbos were predominant. He said tubing, hoses and clamp problems were heat-related and expensive.
McKibben concluded with a reminder that '07 engines are less than a year away and truck buyers will be looking forward to $3,000 to $8,000 higher prices, at least 140 pounds of additional engine weight, higher maintenance costs and the need for major technician training, especially in diagnostics.
