Buyer Research

2020 Peterbilt 579 PACCAR MX-13 — Should You Buy One?

Typical asking price: $80,000–$115,000. There are 2 high-severity known issues you need to know before handing over a check.

Kestrel Take

The 579 is Peterbilt's aerodynamic flagship — fuel-efficient, driver-friendly, and equipped with Peterbilt's SmartNav and optional Bendix ADAS. The MX-13 by 2020 is a mature engine with most early issues resolved. Solid choice for a used long-haul truck with modern features.

What we checked

No public record to reconcile against

We don't yet have a public record to check this one against. Federal complaint records thin out badly on older vehicles, so there is little to check against. What follows is our own write-up, and it has not been reconciled against an official record. Treat it as a starting point, not a verdict.

Known Issues for the 2020 Peterbilt 579 PACCAR MX-13

Ranked by wallet impact. These are documented, recurring problems — not freak accidents.

MX-13 aftertreatment systemHigh — wallet impact

DEF, DPF, and SCR system failures trigger derate modes. Pre-purchase ECM scan is mandatory.

Repair cost (estimate): $500-$4,000

Source: not yet checked against public records.

MX-13 EGR coolerHigh — wallet impact

EGR cooler failures on the MX-13 — white smoke and coolant loss are the indicators. By 2020 the cooler design had improved but not eliminated the concern.

Repair cost (estimate): $2,000-$5,000

Source: not yet checked against public records.

ADAS radar and camera calibrationMedium

Bendix Fusion or OnGuard ADAS requires calibration after windshield replacement. Verify all safety systems active.

Repair cost (estimate): $500-$1,500 to calibrate

Source: not yet checked against public records.

Walk-Away Red Flags

  • Active emissions or engine fault codes on ECM scan
  • White smoke or coolant loss — EGR cooler
  • ADAS warning lights active

Good Signs

  • Peterbilt dealer PM service history
  • ECM scan clean
  • Long-haul highway miles
  • EGR cooler replaced or inspected and documented

Found a specific Peterbilt 579 PACCAR MX-13?

This page covers what goes wrong on the 2020 Peterbilt 579 PACCAR MX-13 in general. The Kestrel report covers this specific car— the asking price vs. market, the photos, the seller's description, and a BUY / NEGOTIATE / WALK AWAY verdict with a negotiation script.

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Not ready to pay for one? The free read is instant and needs no card — it checks the asking price against the market and names the top issues for this year. It stops short of the verdict, because that needs the photos.

Known issues on this page are based on documented owner reports, NHTSA complaints, class-action records, and manufacturer technical service bulletins. Individual vehicles vary. A pre-purchase inspection by a trusted mechanic is always worth doing.

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