There are basically two ways to find out that something on an 18-wheeler needs attention.
The first is during a scheduled maintenance inspection while the truck is sitting safely at the shop.
The second is on the shoulder of I-10 with a loaded trailer, a driver staring at the engine, and everybody suddenly becoming very interested in what that strange noise was 200 miles ago.
I prefer the first option.
I’m Edyce Stone, owner of Dragon Diesel Mechanical in Baton Rouge, Louisiana, and preventative maintenance is one of those things that can seem routine right up until something gets skipped.
An 18-wheeler spends its working life dealing with heat, vibration, heavy loads, long distances, road debris, potholes, stop-and-go traffic, and Louisiana weather. Every component eventually experiences wear.
Preventative maintenance intervals create regular opportunities to find that wear before it turns into something considerably more complicated.
Mileage Doesn’t Tell the Whole Story
Maintenance schedules are often discussed in terms of miles.
That makes sense. Trucks travel for a living. But mileage isn’t the only measurement that matters.
Consider two trucks that each traveled 50,000 miles.
One spent most of those miles cruising steadily on the interstate.
The other spent significant time idling, making deliveries, crawling through city traffic, operating under heavy loads, and stopping constantly.
Those trucks may have the same mileage, but they haven’t lived the same life.
Engine hours, idle time, operating conditions, loads, road conditions, and manufacturer recommendations can all influence maintenance intervals.
The odometer tells part of the story.
The truck tells the rest.
Oil Changes Are Important, but There’s More to PM
Ask most people about diesel maintenance and oil changes immediately come to mind.
They’re certainly important.
Diesel engine oil lubricates moving parts, helps manage heat, carries contaminants, and protects components operating under substantial loads.
Filters also matter.
Oil filters capture contaminants in the lubrication system. Fuel filters help protect the fuel system. Air filters help keep unwanted material from entering the engine.
But a preventative maintenance inspection shouldn’t become an oil change followed by somebody slamming the hood and calling it a day.
There is considerably more truck underneath that hood.
Brakes Deserve Attention Before They Demand It
Stopping an 18-wheeler involves a lot of physics.
And physics does not negotiate.
Brake components experience normal wear every time the truck slows down. Linings, drums, rotors, chambers, hoses, air lines, and related components all need attention.
The important thing about preventative inspection is that wear can sometimes be identified before it becomes a performance problem.
A component doesn’t need to be completely broken to deserve attention.
Cracks, leaks, unusual wear, contamination, looseness, or adjustment issues can provide early clues.
Mechanical equipment has a habit of whispering before it starts yelling.
Maintenance is about listening while it’s still whispering.
Tires Can Tell Stories
Tires are surprisingly talkative if somebody knows what to look for.
Uneven wear isn’t always simply a tire problem.
Wear on one edge might suggest an alignment issue.
Unusual patterns can point toward suspension or steering conditions.
Inflation pressure affects wear, handling, heat generation, and tire life.
Then there are the wheel ends.
Bearings, hubs, seals, and lubrication all deserve inspection.
A leaking wheel seal may initially look like a relatively small problem. Left alone long enough, it can become considerably more interesting.
In heavy-duty diesel repair, “interesting” is rarely the word anyone wants to hear.
Cooling Systems Have a Difficult Job
A diesel engine produces a tremendous amount of heat.
The cooling system spends its entire working life trying to keep that heat under control.
Coolant, radiators, hoses, clamps, thermostats, water pumps, belts, and fans all participate.
A hose rarely wakes up one morning and decides to fail for no reason.
It may have been deteriorating for months.
- Belts can crack.
- Connections can loosen.
- Small leaks can develop.
Preventative maintenance creates opportunities to find those problems while the truck is already at the shop.
That’s considerably more convenient than discovering a coolant problem halfway between Baton Rouge and Houston.
Suspension Components Take a Beating
Louisiana roads provide plenty of opportunities for suspension systems to demonstrate their purpose.
I’ll leave it at that.
Springs, shocks, bushings, air suspension components, steering linkages, kingpins, tie rods, and other parts spend thousands of miles dealing with road surfaces and heavy loads.
Wear in these components can affect handling and tire wear.
Small amounts of looseness can become larger amounts of looseness.
Air leaks don’t usually repair themselves.
Regular inspections provide an opportunity to catch changes before they become bigger problems.
Modern Trucks Are Rolling Computers
Today’s 18-wheelers aren’t purely mechanical machines.
There are sensors everywhere.
Electronic controls manage engine operation, emissions systems, transmissions, electrical systems, and numerous other functions.
Then there are batteries, starters, alternators, wiring, connectors, lighting, and charging systems.
A weak battery or corroded electrical connection can create symptoms that appear and disappear.
Anyone who has ever chased an intermittent electrical problem understands how much fun that can be.
And by fun, I mean almost anything else would be more fun.
Testing components during routine maintenance can sometimes identify electrical conditions before they become roadside problems.
Maintenance Records Matter
One of the most useful tools in preventative maintenance isn’t actually a tool.
It’s history.
Knowing what has been replaced, when fluids were changed, how often certain problems occur, and what inspections previously revealed creates a picture of how an individual truck is aging.
Patterns can emerge.
If the same component repeatedly fails, the component itself may not be the real problem.
Something else may be causing it.
Records also eliminate the highly scientific maintenance system known as, “I think that was changed sometime last year.”
For commercial trucks accumulating serious mileage, guessing isn’t much of a maintenance strategy.
Preventative Maintenance Is Really About Timing
At Dragon Diesel Mechanical in Baton Rouge, I look at preventative maintenance as a matter of choosing when a problem gets attention.
A worn belt discovered during an inspection can be handled while the truck is already down for maintenance.
That same belt breaking on the interstate has now invited a tow truck, downtime, scheduling problems, and probably several phone calls nobody wanted to make.
Preventative maintenance can’t predict every mechanical failure.
Parts still break.
Unexpected problems still happen.
Trucks still occasionally decide to have bad days.
But scheduled inspections create regular opportunities to find wear, leaks, damage, looseness, contamination, and changing conditions before they progress.
An 18-wheeler is built to work.
It can travel hundreds of thousands of miles while hauling enormous loads through some pretty unforgiving conditions.
But even the toughest truck needs attention occasionally.
Because when an 18-wheeler decides it’s done moving, 80,000 pounds of truck and cargo isn’t exactly something that can be pushed to the nearest gas station.
