Q. Why change oil every 5,000 miles in my Ford F-350 with 6.0-liter diesel? I have a friend who owns a New Holland Dealership and he tells me the recommended oil change on older tractors is 300 hours and new tractors are 600 hours. If I average 40 mph in my diesel, then the oil should be changed every 12,000 miles (300 hours) or 24,000 miles (600 hours). Tractors work with a load and in dustier conditions. He has an F-250 with 165,000 miles and has changed the oil five times with no repairs. Is this madness, or are we truck owners being misled by the auto companies? An oil change with 15 quarts of oil and a filter costs big bucks.
– Ed Garman, Chambersburg, Pennsylvania
A. Cold starts are tough on oil. Compared to most pickups, tractors have an advantage there, because they are usually started up and allowed to run all day. Your engine has oil circulating through the fuel-injector system, and the expensive injectors are prone to problems from dirty oil. Tractors generally have good air filters, negating the effect of dust. If you run an hour meter, you’ll also probably find out that your average speed is less than you think, which further changes the miles-per-hour math. Manufacturers are conservative in oil-change-interval recommendations to cover the more severe users and minimize warranty claims. If you have oil-related engine damage and can’t prove the oil was changed within factory-recommended intervals, coverage could be denied. Having a professional oil analysis allows you to obtain scientific information on the condition of your engine and oil. You can find oil-analysis labs via a Web search; one company is Blackstone Labs, (260-744-2380; www.blackstone-labs.com). At various mileage intervals, you can track the accumulation of wear particles, soot and other combustion byproducts in the oil to further help you decide when to change the oil.
–K.F.
Ken Freund has more than three decades of auto-repair experience and 20-plus years of RVing, which has given him the experience and knowledge needed to write the numerous books and articles he has authored on vehicle repair. In addition to RV Clinic and Performance, he writes the Powertrain column in MotorHome magazine. Ken has been a California Automotive VO-Tech and Smog-Test Program Instructor and an ASE-certified Master Automobile Technician.
