A predictable PM schedule is the cheapest insurance against roadside calls. Here’s a simple interval guide based on mileage, hours, and duty cycle for the engines and axles we see most in the Lehigh Valley.

1. Oil & Filters

   Long-haul: 25,000–35,000 mi with oil analysis; Regional/stop-and-go: 15,000–20,000 mi; Severe/vocational: 7,500–12,000 mi. Always pair oil with fuel filters and crankcase filters to keep soot in check.

2. Coolant & Cooling System

   Test nitrite and pH every service, replace coolant filters as spec’d, pressure test cap, inspect hoses for soft spots. Full coolant exchange every 2–3 years or per OEM OAT/NOAT spec.

3. Air System & Dryers

   Replace desiccant cartridges yearly before winter. Drain wet tank weekly, check purge valve operation, and listen for governor cycling too often (sign of leaks).

4. Aftertreatment (DPF/SCR)

   Passive-friendly routes: bake/clean DPF every 250k–300k mi; stop-and-go or idle-heavy: 120k–150k mi. Inspect clamps, flex, and DEF doser at each service; perform forced regen if soot load trends up.

5. Driveline & Axles

   Grease U-joints and slip yokes every 10k–15k mi. Change drive axle fluid every 150k–250k mi (severe) or per OEM spec; check for metallic sheen indicating bearing wear.

6. Brakes & Wheel Ends

   Inspect lining thickness, hardware, and chamber travel every service. Torque wheels, check hub seals for wetness, and verify ABS tone rings are clean for reliable inspections.

7. Electrical & Batteries

   Load-test batteries pre-winter, clean/coat terminals, verify alternator output under load, and inspect starter draw to catch slow cranks early.

How We Run Fleet PMs

- Build a VIN-specific interval table with mileage and hour triggers.
- Sync reminders to your telematics odometer/hours or manual log.
- Perform inspection sheets with red/yellow/green status and photos.
- Stage commonly used filters and fluids for your fleet to cut downtime.
- Track recurring defects to eliminate root causes (driver behavior, routes, or parts).

Set Up a PM Plan

Call 610-419-1247 or book a PM kickoff. We can service in our Allentown shop or send mobile techs to your yard during off-hours.