There’s an eternal principle that experienced big rig drivers live by: Inspect your semi-truck regularly to identify and address minor issues before they become serious and expensive problems. Frequent inspections and routine maintenance can be the reason you arrive at your next stop on time instead of sitting roadside for hours waiting for a service truck. Whether you're a business owner with a fleet of semi-trucks or a proud, independent owner/operator, taking care of your expensive investment is vital. Establishing a schedule for regular maintenance on your truck is the key to worry-free operation and longevity for your semi.
What is covered in this article:
Why Semi-Truck Maintenance Matters
In an industry where circumstances can be unpredictable and outside of your control, there is one factor that you can manage: big-rig maintenance. With scheduled routine maintenance for your semi, you can avoid damage, downtime, and unexpected repair costs. Instead of reacting to maintenance emergencies, identify small issues and schedule repairs at your convenience. Your hauls will keep moving on schedule, and future loads can be easily planned.
These are the four primary advantages of preventive semi-truck maintenance checks.
Safety for Your Team & Equipment
This is the most important reason to keep your big rig properly maintained: protecting your drivers, shipment, and other road-sharing drivers from harm.
Meet DOT Regulations
Once you’re flagged for maintenance issues or violations, you’re in the system. Every out-of-service (OOS) violation must be fixed before the semi-truck is considered roadworthy again.
Avoid Costly Repairs
Performing routine maintenance makes your costs more predictable. Avoid calling emergency roadside service for expensive repairs that eat away at your profits and impact your bottom line.
Increase the Truck’s Lifespan
Maintaining your big rig increases uptime, lowers your operating costs, decreases your cost per mile, and makes your job more lucrative.
Routine preventive semi-truck maintenance helps avoid unnecessary downtime while promoting safe operation. On average, a more detailed inspection for preventive maintenance is performed every 30,000 miles. Refer to your owner’s manual for the recommended service intervals for your truck and always hire a trained professional to perform the work.
- Preventive maintenance services include:
- Oil change
- Oil filter, air filter, and fuel filter change
- Fuel system bleed
- Water separators drain
- Brake inspection
- Exhaust inspection
- Steering and alignment inspection
- Tire inspection and inflation
- Lighting and electrical inspection
- Grease necessary components
- Engine cleaning
- DOT standards repairs
How Often Does My Truck Need Maintenance?
The Federal Motor Carrier Safety Administration (FMCSA) requires the semi-truck owner to “systematically inspect, repair, and maintain all motor vehicles and intermodal equipment subject to its control.” Establishing a preventive maintenance schedule ensures your truck is safe, legal, and ready for the road.
So how often should I service my big rig? It all depends on how often the manufacturer recommends service. On average, the recommended range to receive basic service is every 15,000 – 25,000 miles. Refer to your owner’s manual on when to service your truck, and always have it worked on by a trained professional with semi-truck experience.
These are the factors to consider for regular maintenance:
- Type of truck (different makes and models have different maintenance schedules)
- Mileage
- Oil type and viscosity
- Age of the truck
- Time of year
- Operating environment
How Often Should I Change My Engine's Oil?
The most responsible truck drivers and owners ask this question. Changing your oil is the most common and easiest maintenance, but it is the most effective in protecting your engine from wear and tear. On average, an oil change for a semi-truck is recommended every 25,000 miles. Recent developments in engine efficiency and oil formulations have significantly increased the interval between oil changes. Truckers are now going further between service visits thanks to advances in technology. Refer to your owner’s manual on what type of oil to use and when to service your truck.
So, besides the mileage indicator, how else can you know if it is time for an oil change? Most experienced mechanics recommend looking for these signs:
- The oil looks sludgy.
- The dipstick shows a low oil level.
- The oil sensors detect low oil levels.
- You receive operational maintenance suggestions from the information center.
How to Maximize Your Truck’s Oil Lifespan
While it’s important not to skip routine service for your big rig, you also should avoid performing unnecessary maintenance. Follow these tips to maximize the distance intervals between oil changes:
- Plan routes with minimal stop-and-go traffic.
- Do not idle unnecessarily (in some states, it’s illegal).
- Keep the engine maintained and up to date on service.
- Avoid extreme temperatures.
How Much Does Diesel Maintenance Cost?
Trying to identify an exact amount for maintenance costs is not easy. There are too many makes and models of trucks and variables to consider. On average, expect to pay around $15,000 per year and even more as the truck ages.
Comprehensive Semi-Truck Inspection Checklist
Developing and then using an inspection checklist, also known as a pre-trip (or post-trip) inspection, helps you guarantee that nothing gets left out when it is time for routine servicing. There are three elements to a quality inspection checklist that help identify future semi-truck maintenance tasks:
- Lays out scheduled inspection tasks for potential maintenance
- Identifies defective components to repair/replace promptly
- Helps you commit to a scheduled maintenance program to keep your big rig in safe health conditions
The following list is similar to the surprise roadside inspections and what the Department of Transportation (DOT) reviews during your annual vehicle inspection. This list is considered typical and will vary depending on Federal Motor Carrier Safety Administration (FMCSA) requirements or road and weather conditions.
Perform these inspections before or after each trip or job:
Fluids
- Check for fluid reservoir leaks to ensure liquid is not dripping from a tank, reservoir, connection, or tubing.
- Closely monitor the wiper washer, coolant, power steering, brake fluid, engine oil, DEF, and fuel levels.
- f your dashboard warning lights are activated, refer to your operator’s manual to troubleshoot the fault.
- In Winter months, make sure that you use the winter formulas or include the correct additives to ensure the diesel fuel, coolant, and engine oil do not freeze.
- If any of the tanks, reservoirs, connections, or tubing have leaks, repair or replace them ASAP and top off all fluids as necessary.
Coolant and Cooling System
- Check the coolant level and top-off as necessary with the high-quality coolant recommended by your truck’s manufacturer.
- Visually confirm the coolant solution is clear with a bright tint and free of any debris or replace immediately.
- Check the cooling system hoses and clamps for leaks.
- If possible, test the coolant to see if the freeze point protection is adequate. Use a handheld refractometer, test strip, or hydrometer. If in doubt, send a sample to a lab. A 50-50 solution should protect your engine down to -34 °F.
- Drain, flush, and pressure test the system as per the manufacturer’s service instructions (performed at least once per year).
- Repair or replace any coolant components which are not operating correctly.
Battery and Electrical System
- Check the electrical system for loose connections or frayed wires.
- Clean the corrosion from the battery terminals.
- Test the battery State of Charge (SOC)and charge if necessary.
- Consider replacing the battery if three years old or older.
- Inspect the alternator and the internal wiring of the system.
- If your control panel has active electrical fault warning lights, refer to your operator’s manual to troubleshoot the fault.
- Review the electrical system components for proper operation and repair or replace faulty battery or system parts.
Brakes
- Inspect the brake pads for adequate brake linings.
- Inspect the rotors, drum, and disc brakes for cracks or road debris.
- Check the brake lines for leaks or damage.
- Check the S-cam brake adjusters for the proper amount of slack.
- If your control panel has active ABS fault warning lights, refer to your operator’s manual to troubleshoot the fault.
- If brake system components are not working correctly, repair or replace them immediately.
Lights
- Inspect the tractor and trailer’s headlights, warning lights, flashers, turn signals, and brake lights.
- Inspect the lenses for cracks or holes.
- If any of the lighting system components are not working correctly, repair or replace them.
Air Conditioner and Heater
- Check connections and hoses for leaks or debris buildup.
- If any A/C system components are operating incorrectly, repair or replace them promptly.
Tires and Wheels
- Inspect the tires for dry rot, uneven wear, bulges, cuts, and punctures on the side walls and tread area.
- Inspect retreaded tires for signs of separation.
- Check and maintain the proper tire pressure by referring to the inflation specifications on the tire.
- Inspect tires for tread depth of 4/32 minimum inch on the steer tires and 2/32 of an inch on all other tires according to federal regulations.
- Inspect the rims and lug nuts for cracks or tire damage.
- Equip your semi-truck with tire chains during icy conditions in the winter.
- If any of the tires fail the inspection, have a professional truck technician evaluate your semi for service.
Cab, Trailer, and General Engine Checks
- Inspect the 5th wheel, pin, assembly mounting, and kingpin for cracks or rust.
- Inspect the trailer landing gear for cracks or damage.
- Check the mudflaps for proper positioning (covering the back axle trailer wheels, body load, or tractor).
- Inspect the electrical, brake, and release airlines for tears or cracks.
- Inspect the cab or trailer exhaust system for leaks or soot.
- Inspect the engine's fuel system for leaks.
- Inspect the trailer's steering system for excessive play or leaks.
- Inspect the windshield wipers for proper function.
- In Winter months, inspect the mechanical components, cab, frame, and undercarriage for salt buildup. Wash the tractor, trailer, and undercarriage regularly to remove the corrosive road salt.
- If any parts fail the inspection, have a professional mechanic evaluate the components for proper service.
Recommended Semi-Truck Maintenance Schedule
Following the manufacturer’s maintenance schedule is the best way to avoid unexpected breakdowns. Refer to your owner’s manual on when to service your semi-truck, and always have it worked on by a trained professional.
Here is a general maintenance schedule to use for reference.
| Maintenance Item |
Normal and Heavy Duty |
Severe Duty |
| Oil and Filter Change |
15,000 miles |
10,000 miles |
| 5th Wheel and Kingpin Grease |
Every 3 months or 30,000 miles |
Every 3 months or 30,000 miles |
| Battery Service |
Every 6 months |
Every 6 months |
| Air and Cabin Filters Replace |
Every 6 months |
Every 6 months |
| Shocks Replace |
Every 12 months |
Every 12 months |
| 3-Axle Alignment and Tire Maintenance |
Every 12 months |
Every 12 months |
| Air Filter Fuel Tank Vent |
Every 12 months |
Every 6 months |
| Air Dryer Filter Replace |
150,000 miles |
100,000 miles |
| Power Steering Fluid Filter Replace |
150,000 miles |
150,000 miles |
| Valve Adjustment |
150,000 miles then every 300,000 miles after the first overhead (valve adjustment) |
150,000 miles then every 200,000 miles after the first overhead (valve adjustment) |
| DEF System Service |
150,000 miles |
150,000 miles |
| DPF Filter Clean and Bake |
400,000 miles |
250,000 miles |
| Coolant Filter Replace |
300,000 miles |
150,000 miles |
| Coolant Flush and Replace |
750,000 miles |
750,000 miles |
| Transmission Filter and Fluid Replace |
500,000 miles or 60 months |
500,000 miles or 60 months |
| Fan/Accessory Drive Belt Replace |
300,000 miles |
150,000 miles |
| Differential Oil Replace |
250,000 miles |
150,000 miles |
What Are The Consequences of Poor Semi-Truck Maintenance?
It’s no secret that poor maintenance of your truck will lead to unsafe trips, expensive repair costs, and unnecessary downtime. Remember that your semi is your money maker, so keep it in good working order.
Wise truckers know that if your wheels are turning, you’re earning. The bottom line is that inspections and a detailed maintenance schedule not only save money but promote safer operations and fewer breakdowns. Perform daily pre-trip inspections and follow a maintenance plan so that minor problems do not become costly repairs or replacements. One fleet manager put it this way: With a reliable maintenance program in place, you will appreciate the safe and profitable miles as you drive toward success.
Where Can I Purchase Diesel Engine Parts?
So, where can you buy high-caliber parts to keep your semi-truck running smoothly? The easiest way to purchase diesel parts is to order them online and have them shipped right to you. Diesel Dash offers same-day shipping and convenient store pickup from our select network of locations.
Shop DieselDash.com or call 833-DSL-DASH for diesel engine and truck parts at a great price.
Resource Links
Web
Semi Truck Preventative Maintenance Schedule & Checklist - CloudTrucks
Keep Your Truck Running Optimally With Quality DEF – International Used Truck Center
A Fleet Manager’s Guide to Preventative Maintenance for Semi Trucks - Samsara
Essential Diesel Engine Maintenance Checklist for Truckers - Kelly’s Truck Repair
Truck Maintenance – Why & When You Should Maintain Your Truck - Cargomatic
Why Proper Fifth Wheel Maintenance is Important – TruckingInfo.com
Semi Truck Oil Change Intervals – Rechtien
YouTube
Troubleshooting: #1 Problem and Fix on DEF/DPF Systems - TruxasSales
Scheduled Preventative Maintenance at G&P Trucking Company, Tyler Walker – G&P Trucking Company
How to grease a semi/ How to properly grease a semi-truck/ How often to grease a semi-truck/ - TAT Express Inc.
Trucking Maintenance Basics ALL New Owner Operators MUST KNOW! – Driven Trucking
Top Ten Truck Maintenance Tips – Dan Klepper
18 Wheeler DOT Inspection check list, Semi Air Brake Inspection, Roadside inspection for CMV Driver. – TAT Express Inc.
Repair
Stewart & Stevenson Diesel Service and Repair Locations
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