Fleet Preventive Maintenance Cost Analysis and Scheduling

PM Intervals by Vehicle Class

Light-duty vehicles (cars, pickups, SUVs under 10,000 lbs GVWR): PM A service every 5,000 to 7,500 miles or 6 months. Includes oil and filter change, tire rotation, fluid level check, brake inspection, lighting check, and a multi-point visual inspection. PM B service every 15,000 to 20,000 miles adds transmission fluid check, coolant condition check, air filter, and cabin filter.

Medium-duty vehicles (10,001 to 26,000 lbs GVWR, box trucks, shuttle buses): PM A every 5,000 to 6,000 miles or 90 days. PM B every 12,000 to 15,000 miles adds brake adjustment, u-joint lubrication, and fuel filter. PM C every 25,000 to 30,000 miles adds transmission and differential service, coolant analysis, and detailed chassis inspection.

Heavy-duty vehicles (over 26,000 lbs GVWR, semis, dump trucks): PM A every 10,000 to 15,000 miles or 90 days. PM B every 25,000 to 30,000 miles. PM C every 50,000 to 75,000 miles with full annual inspection. DOT annual inspections under FMCSA 396.17 are required and should be coordinated with PM C service.

Off-road equipment (loaders, excavators, dozers): PM by engine hours, not miles. Typically 250-hour intervals for minor service, 500 hours for intermediate, and 1,000 to 2,000 hours for major service. Manufacturer recommendations take priority over general guidelines.

PM Cost Components: Parts, Labor, and Overhead

Parts cost for a standard PM-A service: light-duty oil and filter $25 to $45, medium-duty $50 to $80, heavy-duty $80 to $150. Synthetic oil adds $15 to $30. Filters (air, cabin, fuel) on PM-B services add $30 to $80 depending on vehicle type. Brake components on PM-C services vary widely from $150 for light-duty pads to $600 or more for heavy-duty shoes and drums.

Labor cost depends on technician pay rate and service time. A PM-A on a light-duty vehicle takes 30 to 45 minutes. A medium-duty PM-A takes 45 to 75 minutes. A heavy-duty PM-C with full inspection takes 3 to 5 hours. At a loaded labor rate of $65 to $85 per hour (including benefits, training, and overhead), labor is typically 50% to 60% of total PM cost.

Overhead includes shop rent or depreciation, utilities, diagnostic tools, lifts and equipment, waste oil disposal, environmental compliance, and management time. A common method allocates overhead at 30% to 50% of direct labor cost. A more precise method calculates actual facility and equipment costs and divides by total billed hours.

In-House vs Outsource Break-Even Analysis

The break-even point for in-house maintenance depends on fleet size, utilization rate of the shop and technician, and local labor market rates. A single full-time technician can handle PM and light repairs for 50 to 75 light-duty vehicles or 25 to 40 medium-duty vehicles.

In-house costs: technician salary and benefits ($55,000 to $85,000/year), shop facility ($500 to $2,000/month rent or equivalent depreciation), tools and equipment ($10,000 to $30,000 initial, $3,000 to $5,000/year ongoing), parts inventory, waste disposal, and management overhead.

Outsource costs: shop labor rate ($90 to $150/hour retail), parts markup (30% to 60% over wholesale), convenience fees, and vehicle downtime for transport. Outsourcing eliminates facility and staffing overhead but costs more per service event.

Most fleets find the break-even at 25 to 40 light-duty vehicles or 15 to 25 medium/heavy-duty vehicles. Below that, outsourcing is typically more economical. Above it, in-house saves 20% to 40% on total maintenance cost. Hybrid approaches (in-house PM, outsource specialized repairs) are common for mid-size fleets.

Hidden Costs of Deferred Maintenance

The visible cost of skipping a $150 PM service is zero saved dollars. The hidden costs are substantial. A missed oil change leads to premature engine wear. At 100,000 miles, a poorly maintained engine may need $4,000 to $8,000 in valve train or bearing repairs that a well-maintained engine avoids entirely.

Roadside breakdowns cost $300 to $800 for towing plus $200 to $500 per hour in lost productivity for the driver and equipment. A single breakdown can cost more than an entire year of PM services for that vehicle.

Fleet vehicles with incomplete maintenance records have 15% to 25% lower resale value. Auction buyers and dealers check service records. A well-documented PM history commands premium resale prices. Over a fleet's lifecycle, this alone can justify the PM program cost.

Scheduling Strategies and ROI Tracking

Schedule PM services based on calendar, mileage, or engine hours — whichever trigger comes first. Fleet management software automates tracking and generates work orders when a vehicle reaches a service threshold. Manual tracking with spreadsheets works for fleets under 20 vehicles but becomes unmanageable above that.

Stagger PM scheduling across the fleet so vehicles come in steadily rather than all at once. If you have 50 vehicles on 90-day PM intervals, schedule roughly 2 to 3 per week rather than 50 every quarter. This levels the workload for technicians and minimizes simultaneous vehicle downtime.

Track ROI by comparing total maintenance cost per mile (or per hour for off-road equipment) before and after implementing a PM program. Industry benchmarks: light-duty vehicles should cost $0.08 to $0.15 per mile in total maintenance. Medium-duty: $0.12 to $0.22 per mile. Heavy-duty: $0.15 to $0.30 per mile. Fleets exceeding these ranges likely have deferred maintenance or aging vehicle issues.