Management & Operations

Small Bus Maintenance Concerns of the Future

Posted on February 1, 2006 by Halsey King

Advanced design and manufacturing requirements of engines and their operating systems have pushed us beyond the “consumables” distinction used to describe yesterday’s iron and steel engines. But in a fleet maintenance environment, antifreeze, coolants, oil, power steering fluids, brake fluids, spark plugs, belts and filters are still referred to as consumables. Engineers and scientists who develop products specified for today’s small bus engines work within many segments of industry and government to provide fleets with high-tech consumables. This interactive work allows them to review today’s operating environment and glance into the needs of the future. In just the past five years, many who operate small buses and vans have seen rapid technology advances in consumable items. Recent advances make it easier to envision, and take advantage of, changes in the future of buses. Antifreeze and coolants
Antifreeze is any of several liquids, including ethylene glycol or propylene glycol, mixed 50-50 with distilled water. When added to a bus cooling system, it will lower the freezing point of the coolant and inhibit the formation of rust and other deposits that can clog the radiator and reduce cooling system efficiency. During the 1960s, ’70s and ’80s, antifreeze was always green. Of course, most bus engines of the time were made of iron or steel, and owners would use antifreeze that fit the engine manufacturers’ specifications and their budget. But, by the mid-80s, engines started becoming smaller, made of aluminum and, in some cases, equipped with silicone hoses instead of rubber hoses. Fleet managers had to revisit their fleet needs for antifreeze, especially in mixed vehicle fleets, where they probably purchased and used several types of antifreeze coolant. It is even more of an uneven playing field today, as each manufacturer has its own unique antifreeze requirements. Both Ford and Chrysler, for example, specify a hybrid coolant that uses nitrite and silicate in the formulation. But neither of these two recommends the same antifreeze that General Motors uses. Don’t let the colors fool you. Yes, antifreeze and coolants now come in more colors that the rainbow, but smart managers compare a product’s labeled specification against the engine manufacturers’ specifications in the engine manual. Service procedures
Most experts agree that bus-cooling systems can be the source of up to 50% of maintenance problems. Issues like overheating, coolant loss, plugged radiators, loose belts and bad water pumps are the result of more than the color or type of coolant. These issues can become the bane of a good technician’s daily work, especially with regard to older buses where the cooling system was ignored, over time. This points to the need for good preventive maintenance service procedures on a regular and consistent basis. The following are several tips you may want to work into your PM program:

  • Purchase the large, three-ring manufacturers’ manual at your local bus dealer and read it cover to cover.
  • Hook up with your dealer service manager and ask about any change notices or service updates issued by the manufacturer.
  • Go online and look up the phone numbers for the manufacturers’ customer service departments. Call and obtain a FIN code, which allows the dealer and manufacturer to know who owns the fleet and where it is located.
  • Purchase special tools and equipment to service your cooling system correctly, and follow the recommended practices outlined by the manuals and dealer. Engine oil basics
    The oil in your bus engine is just one of more than 360 different products that can be refined from a single gallon of crude oil. Maybe you never thought of it that way, but refiners know that process and its profit potential very well. For our purposes, let’s break the refining process down to three levels. We’ll call them top distillates, middle distillates and heavy distillates. 1. Top distillates come from the top of the refining process. These products are made for such uses as cosmetics, medicines and other products that require ultra-refined oil. 2. Middle distillates of crude oil are used for everyday products such as bug sprays, paints, bus fuel systems, cleaners, certain bus trim products, gym shoes, toys and basketballs. 3. Heavy distillates are used to manufacture a host of products that we are very familiar with in the bus maintenance shop. Among these are gasoline, diesel fuel, wheel bearing grease and many more. In our homes and offices, we can see products that are directly manufactured from crude oil or manufactured in concert with other products that result in everyday items. Some of these are roof and floor coverings, the plastic that covers your fax machine, the ink it uses, some of your clothing and the asphalt on the road that we drive our buses on. When refined form crude oil, engine oil is as clear as water and is referred to as “base stock quality oil.” From there, it is shipped to a blender, who mixes in an additive package of chemical products. This additive package helps to protect engine parts during cold days and hot days, guarding against fuel dilution and sludge buildup. It also helps to suspend small particles such as carbon and sand until they are trapped in the oil filter. At a certain time or mileage interval, it is imperative to change the oil and filter because they both can become so contaminated with chemicals that they begin to damage the very parts they are intended to protect. Modern oil considerations
    In the late ’70s, a new product became available to bus fleets in the form of synthetic lubrication. These were not petrochemical-based oils; rather they’re classified as “blended lubrication.” These partial synthetics are available today, as are 100% synthetic engine and transmission oils. Manufacturers say that there are vast differences in the performance of synthetic over petrochemical-based oils.
  • Synthetic oils handle engine heat much better and can help lower operating temperatures by as much as 10 degrees. Reducing engine and transmission temperature extends their life.
  • Synthetic oils have good “suspension quality,” which means that they help keep contamination such as carbon, sand and water afloat until they are trapped in the oil filter. It is now more common for full-sized bus transmission manufacturers to extend warranties to those who purchase and install synthetic oils. Other manufacturers are considering incentives to encourage the switch from petrochemical-based to synthetic oils. Tighter controls are in the works for handling and storage of all oils. In the near term, we may see buses delivered with no oil drain plugs. Shop service technicians will simply vacuum the oil through the dipstick or fill tube, making the EPA happy. The bottom line is, if you can use synthetic oils without violating your warranties, go for it. King has more than 26 years' experience in fleet maintenance.
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