Heavy-duty trucks have undergone significant changes in recent years, mostly driven by government-mandated reductions in emissions. If your preventive maintenance program hasn’t been updated accordingly, your equipment could be spending more time than necessary in the shop.

“Quite often, a lot of fleets are using preventive maintenance programs that may be back-dated a few years,” said Michael Kirby, service director, Altruck International Truck Centres. “We covered two emissions changes in the last five years. The question is, who wrote the PM program, when did they write it and what was it focusing on? And what are the additional systems we are maintaining today that were not included in the original iteration of the PM program when it was written?”

A PM program written in the early- to mid-aughts probably doesn’t adequately cover new emissions-related components such as diesel particulate filters (DPFs) and diesel exhaust fluid (DEF) systems. 

“The DPF has been around since 2008 but we still see guys trying to push it extra miles or they forget about it on the PM cycle,” Kirby said. “As a best practice, try to schedule that to be (cleaned) according to your manufacturer’s specifications, or err on the side of caution with that.”

A DPF that becomes clogged can cause the truck to de-rate or shut down on the side of the road, or can contribute to other engine problems. Several cleaning methods are available so when getting the filter serviced, be sure to use a reputable provider.

“The big thing is to understand your vendor’s cleaning process,” Kirby said. “There are a lot of snake oil guys in the marketplace who will hook up an air compressor and tell you they’ve cleaned the filter out. Others have invested in the proper equipment to do it properly.”

Smaller filters on the vehicle need attention too, including the screen on the DEF tank filler neck.

“Something that’s often overlooked is the DEF filter and auxiliary bunk heater filters,” said Marc Poland, service manager, Sheehan’s Truck Centre. “They are tiny little things, not something you think of, but you can end up with a $4 clogged fuel filter that provides fuel to the bunk heater going and then you end up with a driver who’s cold and ends up running your truck and using fuel.”

Cabin filters are another item that’s often overlooked, according to Mike Allen, service director for Greatwest Kenworth.

“These filters can cause poor air flow and cab air quality and are very easy to service, but as you guessed, they don’t get changed until there is a problem with the unit,” Allen explained.

The desiccant cartridge in an air dryer is another small item that can cause big problems if it isn’t replaced about once a year. 

“What happens is, the air dryer works well in the summer, then you get into winter and because the cartridge hasn’t been changed, a lot more water and contaminants get into the air system and freeze up suspension valves, brake valves – not only on the trucks, but on the trailers,” Poland explained. “Fleets need to be cognizant that their owner/operators are on a similar plan because you can maintain all your company-owned vehicles as well as possible but if you have an O/O who hasn’t had an air dryer cartridge changed pulling your trailers around, it could be one of your company trucks at the side of the road with its brakes frozen or damaged as a result.”

Most service managers we spoke to cited batteries as one of the biggest headaches for fleets.

“Batteries are only occasionally checked over and often not until there is a problem with the unit,” said Allen. “With the increase over the past few years in electrical/electronic requirements, it is important now, more than ever, to keep this system top notch.”

Altruck’s Kirby agreed. “Most of our service calls in winter are quickly resolved with a set of batteries,” he said. “When the truck is getting a PM inspection, hook it up for a load test.”

Kirby also stressed the importance of plugging trucks in when it’s cold outside.

“It sounds silly and at the end of the day everyone is looking to go home, but the big thing is, plug your truck in,” he suggested.

Poland said batteries and connections should be inspected regularly, not only when there’s an issue with starting.

“A lot of people think just because the truck starts, it’s fine,” he said. “But we definitely see issues with connections that are corroded or loose. They should be cleaned and sealed at least every six months.”

The same goes for electrical connections on the starter, Poland added.

Fleets and owner/operators should also monitor the condition of their coolant, especially on trucks that have been in service for a while.

Poland said extended life coolant on a truck that’s been on the road for five years or more may be reaching its best before date.

“We’re seeing trucks on the road now that, unless they have had a cooling system repair where the system had to be drained, they could be running on fluid that’s really old and can cause all kinds of problems inside the engine,” Poland warned.

Mechanical items on a truck, if not monitored as part of a PM program, can cause problems, as well.

Allen said suspension bushings and spring pins are usually inspected annually but should be examined throughout the year because “they can fail and cause different concerns, for example tire wear and steerability issues.”

While oil manufacturers have been producing better heavy-duty engine oils, allowing OEMs to extend engine oil drain intervals, Poland said some fleets are mistakenly assuming the same extensions apply to the lubrication of other components.

“OEMs are pushing out oil change intervals, so you’re seeing something that was changed at 40,000 kms pushed out to 50,000, 60,000 kms,” Poland said. “What happens is, some people aren’t maintaining the lubrication intervals for the chassis. We’re seeing stuff coming in with seized king pins and that sort of thing because it hasn’t been greased as it should have been.”

In addition to regularly monitoring problematic components and systems, fleets should also advise drivers on how to protect these systems from premature wear.

The easiest way drivers can help, according to Don Bailey, director of parts and service operations for Custom Truck Sales in Winnipeg, Man., is to reduce idling.

“The consensus number one item operators of heavy-duty vehicles can take action on to improve reliability and at the same time lower costs, is to keep engine idle time to a minimum,” Bailey said. “It is our experience that the lower the idle time, the fewer visits to a service provider a vehicle experiences.”

Reducing idling time also extends engine and emissions aftertreatment system life. Bailey said drivers can also help reduce downtime but conducting thorough pre-trip inspections, which should include checking all fluid levels.