Article by Rob Lowe
Routine Maintenance on Diesel Vehicles
This category of diesel-powered vehicles is divided into two types. The first is a towing vehicle used for trailer-towing such as a pickup truck. The second is a diesel-powered motorhome with either a front or rear engine powertrain.
Hint: Clean oil is your engine’s life-blood. Always use high quality oil at the recommended viscosity together with a name brand oil filter. It’s okay to buy name brand oil and filters on sale, don’t buy an off-brand. That is false economy!
The vehicle used for trailer towing, such as a pickup truck, has service intervals similar to that of modern gasoline engines with extended service intervals for oil and filter changes. It is imperative that RVers consult and follow the truck manufacturer’s Maintenance Schedule. Since these trucks are designed to be used in a towing environment, the schedule can be relied upon to be suitable for RV usage.
For diesel-engine equipped Type B or Type C (van style) RVs, the Maintenance Schedule will be similar to those used in diesel pickup trucks or cars. Other than focusing on the time frames rather than distance traveled, most maintenance regimens recommended by the manufacturer should be followed.
The Type A motorhome Maintenance Schedule for the diesel-engine equipped RV chassis is targeted to “Highway Transport” use with hundreds-of-thousands-of-miles being clocked each year. This driving schedule is irrational for typical RV usage where the annual mileage often falls between eight and 20,000 miles (12,800 to 32,000 kilometers). Generally for an RVer the oil change interval will be once per year,
regardless of the mileage.
These engines usually hold much large quantities of oil than a comparable gasoline engine. Because of the large quantities of oil, the effect of condensation and oil contamination is less. These long oil-change intervals are designed to make it practical for truckers to run greater distances and return to their home base to have service completed. Time is money in these applications, so service on the road is the loss of income-producing time.
Most diesel-engine makers recommend fuel filter/water separator changes at the same time as the oil change interval. Some engines have multiple fuel filters, one of which, the primary filter, is mounted in an accessible location and another secondary filter is mounted on the engine. Some systems have water-in-fuel warning lights while others have a drain on the bottom of the fuel/water separator. Learn which system is on your RV and follow the maker’s recommendation for service or replacement.
Chassis Lubrication and Engine Oil—Change Interval
The annual oil change is a different interval than the engine lubrication interval. Typically the chassis lubrication of multiple fittings on the steering, suspension, air brakes, exhaust brake, and drive train, are every 3,000 miles (5,000 km) or every three months. For a seasonal RVer this will require that chassis lubrications be evenly spaced throughout the season. Fluid levels of the transmission, engine, rear axle, power steering, and radiator should be inspected at each lubrication interval. In addition the wheel lug nuts should be re-torqued to specifications.
Annual lubrications and inspections may include:
- checking belts
- air compressor filter change/cleaning
- hydraulic filter change
- coolant filter change
- replacing front axle oil (some diesel chassis)
- The strength and PH level of the coolant should be checked using the approved strips
- Addition of cooling system supplemental coolant additive (SCA) to rebalance the PH and extend protection
- Some engines require valve lash be checked and/or adjusted after two years of service
- Turbo chargers, water pumps, belt tensioners, crankshaft vibration dampers, air filters, engine mounts, radiators and charge air coolers need to be inspected
- Fan and fan shrouds should be inspected
- Allison Transmission Filters usually are changed every two years with Transmission fluid (TranSynd™) should be changed every four years.
The air suspension and air braking systems each have routine maintenance schedules that should be carefully followed. In most states and provinces only mechanics with air brake certification can inspect or make adjustments to these systems.
Tires should be inspected for any nicks or cuts in addition to checking the air pressure when cold. As tires age they deteriorate from ozone and ultraviolet light. Determine the production date of your tires, when they become five years old, carry out monthly inspections of the tires. Look for small hairline cracking in the sidewall, which is the beginning of the end. While RV style tires are designed to last longer in RV use, these tires should be replaced when they are six years old.