2023 Peterbilt 579 Spark Plug Type & Gap
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Quick reference
| Engine | OEM Plug PN | Aftermarket (NGK/Denso/Motorcraft) | Gap (in/mm) | Torque (lb-ft / Nm) | Interval |
|---|---|---|---|---|---|
| PACCAR MX-13 | N/A (Diesel) | N/A (Diesel) | N/A (Diesel) | N/A (Diesel) | N/A (Diesel) |
| Cummins X15 | N/A (Diesel) | N/A (Diesel) | N/A (Diesel) | N/A (Diesel) | N/A (Diesel) |
Why the right plug matters
For natural gas or gasoline engines, spark plugs are critical for proper combustion. However, the 2023 Peterbilt 579 is exclusively offered with diesel engines (PACCAR MX-13 and Cummins X15). Diesel engines operate on a compression-ignition principle, meaning they do not use spark plugs to ignite the air/fuel mixture. Instead, they rely on high compression to generate enough heat to ignite the fuel spontaneously.
Therefore, concerns about spark plug heat range, electrode material (iridium, platinum, copper), gap, and torque specifications are not applicable to this vehicle.
How to gap a spark plug
This section is not applicable as the 2023 Peterbilt 579 uses diesel engines.
Replacement procedure tips
This section is not applicable as the 2023 Peterbilt 579 uses diesel engines. Diesel engines often use glow plugs to aid in cold starting, but these are distinct from spark plugs and serve a different purpose.
Known issues
As the 2023 Peterbilt 579 utilizes diesel engines, common gasoline engine spark plug issues such as cracked porcelain, broken plug shells, or ionization-sensing coil problems are irrelevant to this vehicle.
Need plugs replaced? Find a shop on Repairius.
More specs for the 2023 Peterbilt 579
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
Battery Size & Group
Group size, CCA, AGM/flooded, dimensions, reset note.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Fuse Box Diagram & Amperage
Fuse box locations, layout, amps, and what each fuse controls.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Transmission & Axle Gear Ratios
Trans gear ratios, axle ratios, RPO codes, tow vs MPG impact.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
Maintenance & repair guides
2023 Peterbilt 579 Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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Values can vary by engine, trim and build date; check your VIN-specific service information. Updated 2026-06-23.