Preventive maintenance starts before a vehicle even sees the inside of the shop; it really begins when a fleet specs its equipment

Ask Mike Lowrie to define "preventive maintenance" (PM) and he'll respond with a one-word answer: "money."

Lowrie, president and owner of Mike Lowrie Trucking, Dixon, Calif., relies on a fleet of 152 Peterbilt 379 tractors to haul sand, gravel and asphalt for highway construction projects in Southern California. Yet for three months out of the year, his trucks haul almost nothing but tomatoes for Heinz Corp., the world-famous maker of ketchup and other savory sauces.

When hauling tomatoes, Lowrie's fleet operates around the clock from July to September. During that time, he can't risk having any of his trucks break down, since Heinz's plant relies on him to deliver a steady stream of fresh tomatoes.

"Once the cannery fires up on July 1, it runs 24 hours a day, 7 days a week, for 100 days straight," Lowrie says. "It needs a constant flow of fruit to keep operating. Consequently, the trucks we have hauling tomatoes never shut down; maintenance is critical."

"We've got to grease those trucks and change the oil on time to achieve longevity and durability. During tomatoe season, our trucks turn 8,000 miles a week, so we only have time to change the oil and oil filter, grease them and get them back on the road."

Yet Lowrie doesn't rely on his mechanics alone to keep the trucks rolling. He believes that by investing more money in his trucks up front he helps support his mechanics' efforts.

"It's worth spending a little more money up front to get more durability," Lowrie explains. "We're running in 100-degree days from July to September, so spec'ing more power - 370- to 400-hp. engines - gives us more longevity to handle the heat."

Theory counts, too According to Jim Pirie, applications engineer for International Truck & Engine Corp., developing good preventive maintenance programs revolves around answering two questions: "What do I have to do to keep components from wearing out prematurely?" and "What can I do to catch component failures before they happen?"

Answering the first question is easy, said Pirie. "Keeping things from wearing out means changing the engine oil, air filters, coolant and other items at the proper intervals," he explains. "These are items with finite life spans that need to be replaced when wear limits are reached."

Answering the second question is harder. "Take engine belts, for example," says Pirie. "They're part of a group of items with no finite life span, yet you have to catch them before they break down. Knowing what this point is can be complicated. It can be affected by lots of outside influences, including external climate, internal temperature cycles and other extraneous circumstances."

In one instance, Pirie worked with a Florida-based trucking fleet that experienced major cooling problems twice a year that impacted vehicle life cycles. The reason? A plague of insects.

"Twice a year, this one area of Florida gets deluged with bugs," he explains. "They pack the radiators of the trucks, reducing cooling ability for long operational stretches. This means a change in PM cycles."

The same situation presents itself in the construction, feed-lot and tree-trimming industry, where airborne dirt, chaffe and wood particles can block truck radiators. Normal PM schedules need to be adjusted to keep vehicles clear and functioning.

PM guideline Two of the most critical elements in developing good PM programs, says Pirie, are communication with mechanics and manufacturers, and understanding every aspect of your fleet's operational climate and how it affects vehicle maintenance. "Keeping the technicians at our 500-plus dealers - not to mention customers - informed is difficult. We send just tons of literature on engines alone to our dealers."

Pirie says regular information bulletins on items ranging from cold- and hot-starting tips to fixing small glitches, are things "technicians cry out for."

Getting feedback from customers is also vital because they "work with the equipment day in and day out," Pirie explains. "I can guarantee you there's someone out there who has learned a good maintenance technique from a situation we can't reproduce in the lab."

Fleets must also understand how operational patterns affect the maintenance intervals for their vehicles, says Pirie. Dozens of external and internal circumstances that can severely affect the operational uptime of equipment have to be taken into consideration.

"Fleets must dissect their operation completely, especially in hard-use environments such as garbage collection and construction," Pirie says. "Maintenance intervals are set at nominal miles and hours levels, but operational patterns affect those intervals. The trick is to find the spot where engine oil, for example, does not have an excessive amount of life left in it, but well before the wear rate from 'poor' oil can affect the engine. Operational patterns have everything to do with finding that spot."

These are not low-cost issues. An oil and filter change alone can run $100 per truck, so changing both too soon for an entire fleet can substantially raise maintenance costs. Yet if the oil and filter are changed too late, the fleet can risk wrecking its motors, causing even higher maintenance costs, along with revenue lost from vehicle downtime.

"You have to find the spot between over-servicing the vehicle, which costs more maintenance dollars, and under-servicing it, which can cost you the engine or worse," Pirie says.

Smart spec'ing Many fleets and manufacturers see improving vehicle specs as the key to solving the majority of PM riddles.

"We're looking at the design criteria and focusing on building low- or no-maintenance components into trucks," says Keith Harrington, manager of product marketing for Freightliner Corp.

"For example, we're now working with long-life engine coolants in our trucks," he points out. "Instead of replacing the coolant every three years, we test it to make sure the pH balance is correct and put in additives and protectorates when needed. Updating the coolant, rather than replacing it, substantially reduces PM costs."

Harrington also points to automated mechanical transmissions (AMT), such as the Eaton 10-speed AutoShift, as another example. "With the AutoShift transmission, drivers only need to use the clutch to start and stop the vehicle. The rest of the shifting is handled automatically," he says. "That greatly reduces wear and tear on the clutch and transmission. Basically, in this situation, you could get a clutch to last the life of the truck."

Spec'ing synthetic lubricants can also reduce costs by extending baseline intervals, adds Ramin Younessi, Freightliner's director of product marketing. "We're seeing increased use of synthetics in engines, transmissions and axles. We think we can push those [baseline] intervals to 100,000 miles."

Brakes are another area where design criteria can substantially extend PM intervals - and reduce costs. Brake pads on Freightliner's CamLaster brake, for example, have an extra inch of lining for a three-year projected life span. According to Freightliner, the CamLaster brake package, developed in conjunction with Meritor Automotive, requires no external adjustment or lubrication and is projected to go 500,000 miles before the first reline is needed. That cuts way back on brake PM costs.

All of these items cost more money up front. Yet Younessi believes that fleets must weigh that up-front cost against the maintenance savings over the projected trade-in cycle for their vehicles. "Most of our customers have a three- to four-year trade-in cycle, so if you have no oil changes in that cycle, for instance, you save a lot of dollars you would otherwise spend on maintenance," he points out.

The proper pieces Spec'ing, of course, goes beyond merely buying the latest components to hit the market. For PM purposes, components need to "match" operational requirements. If a vehicle is underspec'd, more maintenance work may have to be done over its life cycle.

"With engines, you need to look at the horsepower-torque curve to get the most amount of engine power while operating at lower rpms; this, in turn, lowers the need for maintenance," Harrington explains.

The dump trucks of Siskiyou County, Calif., provide a good example. Adjacent to the southern border of Oregon, Siskiyou is California's fifth largest county. Some 60% of the county's land is made up of national forests, wilderness areas and wildlife refuges maintained by the federal government.

Yet the same beautiful landscape makes life tough on the trucks used by Siskiyou's Public Works Dept., which has to keep 1,400 miles of road and 175 bridges open. Snowstorms can make clearing the roads a nightmare in winter, while heavy rains can trigger floods, rock slides and worse along the county's many steep mountainsides.

That's where the county's fleet of 600-plus vehicles comes into play, and and where truck specs, especially on its 22 ten-yard dump trucks, can make the difference between success and disaster. Virgil Hardy, equipment supervisor, explains that the county's trucks must operate in high elevations - sometimes more than 10,300 ft. above sea level - while fully loaded.

Hardy specs Siskiyou's twin-axle Kenworth T-800s with Caterpillar 3406 electronic diesel engines, Eaton 13-speed double overdrive transmissions, and 14,500- to 16,000-lb. front axles to handle steel plows that weigh between 1,800 and 2,300 lb.

The trucks, which sport 200-in. wheelbases, are spec'd with load boosters on the front and rear axles to gain an 80,000-lb. GVWR. This rating is critical as the trucks must carry spreader devices weighing 6,500 lb. unloaded to spread crushed volcanic rock cinders during winter to keep the roads clear of snow. Volcanic cinders, a plentiful geological by-product in Siskiyou, is cheaper than sand and weighs 1,500 lb./yd. Add 10 yd. of cinders to a 6,500-lb. spreader and 2,300-lb. plow, and you have a 26,000-lb. load for Siskiyou's dump trucks to haul in the winter.

As if that wasn't enough, some 22 of the county's 30 dump trucks are also equipped with towing hitches so they can haul 8- to 10-yd. dump trailers to maximize productivity at job sites year-round.

Engine specs are crucial to successful year-round, heavy-duty use. That's why Hardy upgraded the county's dump truck engines from 3208 Caterpillar diesels to 3406s, gaining higher horsepower as well as better fuel mileage. "The 3406s are spec'd to run at 415 to 435 hp.," Hardy says. "That means the engine doesn't have to work as hard at the higher horsepower, so they last longer."

The higher horsepower electronic engines also come with better fuel economy, which adds up to substantial savings for the fleet. "The 3208s averaged 3.6 mi./gal. The new 3406s average between 6.5 and 7.6 mi./gal.," he says. "Projected over 10 years, it's a huge savings."

Higher horsepower is also key to extending the life of Siskiyou's dump trucks and cutting maintenance costs. Hardy says the 315-hp. 3208s hit the limit of their useful life between 300,000 and 350,000 miles. With higher horsepower 3406s in place to better manage the workload, the T-800 fleet can reach 500,000 to 550,000 miles before they need to be replaced.

Tracking Maintenance Hardy also invests heavily in oil analysis for the fleet's heavy equipment, especially its dump trucks, and tracks all maintenance via a software program from Peregrine Systems. "We need to stay on top of the manufacturer's recommended PM schedules, and the software allows us to do that," he says.

"And because of the environment we work in, we use extensive oil analysis. We also use the lowest suggested oil-change interval for all of our engines, whether they are from Caterpillar, Cummins or Detroit Diesel." If we pay a little more up front with more frequent oil changes, we can avoid more expensive problems down the road."

Tire wear is also watched closely. "We get accelerated wear from the chains we use in the winter," Hardy explains. "We'll recap tires twice if the tire casing will allow it. We also keep a close eye on tire wear on the heavier equipment."

Down the road "In the future, we'll have to pay more attention to electronics to help fleets develop better PM practices," says International's Pirie. Electronically generated diagnostic information - especially when it comes to engine maintenance - will be critical to PM program development.

"One of the things that's most underutilized today is the onboard computer on engines and other truck components to help fleets find their optimum service intervals," he says. "Right now, only 5% of our customers are using that feature. That information can prove invaluable in helping fleets find the right intervals from their own operational data."

Freightliner's Younessi also believes such self-generated information will be critical to finding the right PM intervals for fleets.

"An option with our electronic onboard data logging units is the capture of information that goes above or below parameters set by the customer," he says. "If anything goes outside of those set parameters, the data logger will track it. That information will help mechanics when it comes to troubleshooting particular maintenance problems."

More detailed dash displays can also help involve a key PM program participant - the driver. "Fault code messages can give drivers a heads-up if something is wrong, such as low engine coolant, and that information can be transmitted back to the home office for analysis," Younessi points out. "This is a good way to stave off a potential maintenance road call."