2019 International ProStar Cummins ISX15 — Should You Buy One?
Typical asking price: $52,000–$78,000. There are 2 high-severity known issues you need to know before handing over a check.
Kestrel Take
The International ProStar with Cummins power is a popular choice in fleets — the combination of International's cab and Cummins' proven engine is well-regarded. The ProStar itself has fewer fans than the LoneStar, but it's a capable long-haul truck at a lower price point.
What we checked
Not checked against public records
No federal database covers this category in a form we can match to a single year and model. 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 2019 International ProStar Cummins ISX15
Ranked by wallet impact. These are documented, recurring problems — not freak accidents. How we decide that.
Same DEF/DPF/SCR concerns as all modern Cummins engines. ECM scan mandatory before purchase.
Repair cost (estimate): $500-$4,500
Source: not yet checked against public records.
EGR cooler failures and valve fouling are documented on ISX15s at higher mileage. Coolant loss signals cooler failure.
Repair cost (estimate): $1,500-$4,000
Source: not yet checked against public records.
ProStar cabs had documented ergonomic complaints and some electrical system issues. Diamond Logic faults are the main electrical concern.
Repair cost (estimate): $200-$1,200
Source: not yet checked against public records.
Walk-Away Red Flags
- ✗Active fault codes on ECM scan
- ✗Coolant loss or white smoke — EGR cooler
- ✗Multiple electrical system faults or warning lights
Good Signs
- ✓Cummins dealer engine service records
- ✓ECM scan clean
- ✓Cummins-powered ProStar preferred over A26-powered ProStar for long-term reliability
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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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