Preventative Maintenance Checklist for Semi Trucks

30th Sep 2025

In this post, we’ll cover the need for a preventative maintenance checklist, and some of the common replacement parts you can buy online and ship directly to your specified address.

Why Preventative Maintenance Matters for Semi Trucks

Your truck is your income, making preventative maintenance a core business strategy. Treating PM as a priority rather than an afterthought extends the life of your rig and prevents catastrophic roadside failures.

The Benefits of PM:

Lowers repair and unexpected overhead costs.
Improves overall fuel efficiency.
Extends the lifespan and resale value of your truck.
Prevents critical failures like overheating, brake failure, tire blowouts, and electrical shutdowns.

How to Build a Preventative Maintenance Plan

Assess the Truck: Note the current mileage, driving frequency, typical weather conditions, and fuel system health.
Build a Schedule: Keep a logbook (binder or spreadsheet) tracking tasks, dates, mileage, and when the next service is due.
Communicate: Set clear expectations with drivers. Fleet managers should use apps like KeepTruckin, Fleetio, or SimpleTruckELD to manage this at scale.
Document Everything: Keep a running record of performance checks, service repairs, and your cost-per-mile to help with budgeting.

Daily & Routine Maintenance Checklist

Catching small issues before they become expensive repairs requires a consistent routine.

Daily (Pre-Trip & Post-Trip)

Tires: Check pressure and minimum tread depth (4/32" on steer tires, 2/32" on others).
Fluids: Verify engine oil, coolant, brake fluid, power steering fluid, and washer fluid. Keep spares in the cab.
Visibility: Inspect wiper blades, brake lights, and marker lights.
Walk-Around: Check for airline leaks, cracked suspension components, and loose connections.

Weekly

Inspect hoses, belts, and filters.
Re-check all fluid levels.
Test dash gauges, interior/exterior lights, and the horn.
Inspect wiring and clean electrical connections.

Monthly

Rotate tires and inspect lug nuts for rust or moisture buildup.
Deep-check the brake system (pads, drums, hydraulic/air lines).
Check wheel alignment, shock absorbers, bushings, and linkages.

Long-Term Service Intervals (By Mileage)

Note: Heavy-duty cycles change service intervals. Steady highway linehaul can stretch intervals, while stop-and-go, heavy loads, or extreme temperatures shorten them. Always confirm with your manufacturer.

Mileage / Time	Service System	Maintenance Tasks
10k–25k mi or 6 months	Routine / Engine	Change engine oil and filter. Inspect air and fuel filters. Check belts, compressor, and gearbox.
100k–150k mi	Air System	Replace air dryer desiccant cartridge. Check DEF system. Adjust valves according to OEM recommendations.
250k–400k mi	Aftertreatment	Clean or bake the DPF. Inspect the doser and DEF quality. Check sensors, clamps, and exhaust leaks.
500k mi or 60 months	Driveline	Replace transmission fluid and filters. Inspect clutch, shift linkages, and differential fluids.
750k mi	Cooling	Flush and replace coolant. Pressure-test the system and cap. Inspect hoses, water pump, and fan clutch.

Swipe horizontally on mobile to view the full maintenance table.

Seasonal Maintenance Needs

Weather fluctuations drastically impact a commercial vehicle. Prepare your rig accordingly:

Winter Preparation

Inspect defrosters and replace wiper blades.
Check the braking system for moisture or ice buildup.
Wash the undercarriage frequently to prevent salt corrosion.
Monitor air pressure, which drops in cold weather.

Summer Preparation

Flush and service the cooling system to prevent overheating.
Monitor tire pressure closely, as extreme heat increases PSI.
Test the air conditioning and electrical systems.

Compliance & Sourcing Parts

Staying on top of maintenance doesn't just save money; it keeps you legally compliant.

Who is checking your truck?

FMCSA: Mandates federal preventative maintenance requirements.
CVSA: Sets the North American Standard Inspection criteria used at weigh stations.
State Troopers: Perform real-time roadside safety and compliance inspections.

Shop for Diesel Truck Parts at 4 State Trucks

Be prepared for preventative maintenance with our broad selection of mechanical parts for your engine, AC, exhaust, and transmission system. Get any component you need shipped to your preferred location quickly and easily when you shop at 4 State Trucks. Questions about a part? Give us a call!

30th Sep 2025