How Often Do Semis Need Maintenance?
If you operate a semi-truck or manage a fleet, knowing how often semis need maintenance is essential for reliability, safety, and profitability. Regular maintenance keeps your truck on the road, prevents costly breakdowns, and ensures compliance with federal inspection requirements.
Based on industry standards and real-world experience with owner-operators across the country, most semi-trucks should follow a service interval between 10,000 and 20,000 miles, or roughly every 3 to 6 months. However, the right interval depends on your routes, loads, and truck condition.
Why Regular Maintenance Matters
Routine maintenance isn’t just about following rules—it’s about protecting your investment and avoiding downtime.
Key benefits include:
Fewer breakdowns: Prevent small issues from turning into expensive repairs.
Improved safety: Ensures brakes, tires, and systems perform properly on the road.
Lower operating costs: Well-maintained engines run more efficiently, saving on fuel.
Better resale value: A clean service history increases your truck’s market appeal.
Regulatory compliance: Keeps your truck in line with FMCSA inspection standards.
Typical Maintenance Intervals for Semi-Trucks
Mileage-Based Service Intervals
Most heavy-duty trucks require basic service every 10,000–20,000 miles.
Trucks with synthetic oil and steady highway mileage may stretch to 25,000 miles.
For older engines or trucks running in harsh conditions, stay closer to 10,000–12,000 miles.
Time- or Usage-Based Intervals
Even if mileage is low, schedule service every 3–6 months to inspect wear items, fluids, and systems.
Components like batteries, hoses, and belts should be checked on a calendar basis rather than mileage.
Trailer Service Intervals
Semi-trailers often require inspections every 25,000–50,000 miles, or every 3–6 months.
Focus on brakes, air systems, suspension, lights, and landing gear.
Rule of thumb: Start with 10,000–15,000 miles or 3–6 months, and adjust based on performance data and environment.
Factors That Influence Maintenance Frequency
1. Route Type and Operating Conditions
Long-haul routes with consistent highway miles may allow longer intervals.
Regional or local routes with frequent stops, heavy loads, or rough terrain require shorter intervals.
Extreme climates—hot, cold, or wet—accelerate wear on fluids, seals, and tires.
2. Truck Age, Engine Type, and Oil Quality
Older trucks need more frequent checks for leaks, vibration, and engine wear.
Synthetic oil may extend intervals but still requires regular inspection.
Always follow your OEM manual for precise service timelines.
3. Trailer vs. Tractor Maintenance
The tractor focuses on engine, drivetrain, and electrical systems.
The trailer needs structural and braking system inspections.
Each should have separate maintenance logs and inspection records.
4. Preventive vs. Reactive Maintenance
Preventive maintenance means servicing on schedule, not waiting for a failure. Fleets that follow preventive plans report significantly lower repair costs and downtime.
Semi-Truck Maintenance Schedule Example
Daily or Pre-Trip Checks
Inspect tires, lights, and brakes.
Check oil, coolant, and air pressure.
Note leaks, noises, or dashboard warnings.
Every 10,000–15,000 Miles or 3–6 Months
Change oil and filters (engine, fuel, and air).
Inspect brakes, belts, hoses, and suspension.
Check tires for tread depth and uneven wear.
Lubricate fifth wheel, landing gear, and chassis.
Inspect electrical and lighting systems.
Every 50,000–60,000 Miles or Annually
Perform full transmission and differential inspection.
Flush coolant system if required.
Check frame, alignment, and undercarriage.
Conduct a detailed brake and suspension evaluation.
Seasonal Maintenance
Summer: Check coolant strength, tire pressure, and A/C system.
Winter: Inspect heater, defroster, and brake air lines for moisture or freeze.
Building a Preventive Maintenance Plan
Log mileage and engine hours: Helps you predict service needs accurately.
Use telematics or fleet software: Automate reminders and maintenance tracking.
Train drivers for inspections: Daily checks reduce breakdown risk.
Keep detailed records: Supports warranty claims and resale value.
Review performance monthly: Adjust intervals if certain systems wear faster.
Conclusion
Semi-truck maintenance isn’t a one-size-fits-all process. The general rule is every 10,000–15,000 miles or 3–6 months, but factors like load weight, routes, and truck age play a big role. A consistent preventive maintenance schedule extends lifespan, improves safety, and saves thousands in repair costs.
Keep your maintenance plan proactive, your records detailed, and your trucks in peak condition—because time off the road costs more than time in the shop.
FAQ
Q1: How often should a semi-truck get an oil change?
Most semis need an oil and filter change every 10,000–15,000 miles, though modern synthetic oils may allow longer intervals.
Q2: Do trailers need separate maintenance schedules?
Yes. Trailers require brake, air system, and structural inspections every 3–6 months or 25,000–50,000 miles.
Q3: What’s the risk of skipping scheduled maintenance?
Skipping service can lead to breakdowns, higher fuel consumption, and costly engine repairs. Preventive maintenance always costs less than emergency repairs.