2023 Peterbilt 389 Serpentine Belt Guide
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Quick Answer
- Belt Length: 2108mm (83 inches)
- Rib Count: 8-rib
- OEM Belt Part Number: Peterbilt 07-08308
- Aftermarket Belt Cross-References: Gates K080830, Dayco 5080830, Continental Elite 4080830
- Auto-Tensioner Part Number: Peterbilt 07-08308AT
- Idler Pulley Part Number: Peterbilt 07-08308IP
Belt Routing
Before you begin, we strongly recommend taking a clear photograph of the current serpentine belt's routing to avoid any confusion during installation. The belt winds its way around several engine accessories in a specific order. For the 2023 Peterbilt 389, the belt path is as follows:
- Starts at the crankshaft pulley at the bottom of the engine.
- Wraps around the A/C compressor.
- Goes over the idler pulley.
- Around the alternator.
- Down to the power steering pump.
- Up and around the water pump.
- Finally, it goes to the auto-tensioner, which maintains the correct belt tension.
How to Replace the Serpentine Belt
To replace the serpentine belt, you'll need a serpentine belt tool or a 3/8" breaker bar. Insert the tool into the square hole on the auto-tensioner and rotate it to release the tension on the belt. While holding the tensioner, carefully slip the old belt off the pulleys.
Before installing the new belt, double-check that the routing is correct by referring to your photo. Start by routing the new belt around all the pulleys except for the idler pulley. Once the belt is in place on the other pulleys, release the tension on the tensioner again and slide the belt over the idler pulley. Slowly release the tensioner to apply tension to the new belt. Ensure the belt is properly seated in the grooves of each pulley.
Replacement Interval
We recommend inspecting the serpentine belt at every oil change and replacing it every 30,000 to 50,000 miles, or as recommended in your owner's manual.
Signs of a Failing Belt or Tensioner
Be on the lookout for these signs that your serpentine belt or tensioner may need replacement:
- Squealing or chirping noises from the engine bay
- Visible cracks, fraying, or glazing on the belt
- The A/C or power steering is not working correctly
- The engine is overheating
- The "battery" or "check engine" light is on
If you notice any of these symptoms, it's time to inspect your serpentine belt and tensioner.
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More specs for the 2023 Peterbilt 389
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.
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.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
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 389 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 2026-08-23.