Recall 11V480 affects 1,825 2011-2012 Thomas Built Buses Saf-T-Liner C2, Mvp-Ef, and Hdx buses for failing exhaust clamps. Repairs are free at authorized Cummins dealers.
Thomas Built Buses is recalling 1,825 2011-2012 Saf-T-Liner C2, Saf-T-Liner Mvp-Ef, and Saf-T-Liner Hdx school buses because a V-band clamp T-bolt on the diesel exhaust aftertreatment system can fracture. Hot exhaust can vent before the tailpipe, which raises fire risk, and the dealer repair will be free once available.
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What's wrong?
The V-band clamp assembly on these 2011-2012 Thomas Built Buses Saf-T-Liner Mvp-Ef, Saf-T-Liner C2, and Saf-T-Liner Hdx school buses holds parts of the diesel exhaust aftertreatment system together. It connects the inlet and outlet cone sections to the diesel oxidation catalyst and diesel particulate filter, the housing that helps clean diesel exhaust before it leaves the bus.
The weak point is the T-bolt inside the clamp. That bolt supplies the clamping force that keeps the band tight around the exhaust housing. On affected buses with Cummins ISX or ISL diesel engines, the T-bolt can fracture when it is under stress or load. Once the bolt breaks, the clamp loosens and the inlet or outlet section attached to the DOC/DPF housing can disconnect.
There is no warning sign before failure. A driver or technician would likely discover the problem after the clamp has loosened or the exhaust aftertreatment section has separated.
Who's affected?
Spans Saf-T-Liner Mvp-Ef, Saf-T-Liner C2, and Saf-T-Liner Hdx buses across the 2011 and 2012 model years, all involving the same engine and engine cooling component.
| 2012 Thomas Built Buses Saf-T-Liner Mvp-Ef | Engine and engine cooling |
|---|---|
| 2011 Thomas Built Saf-T-Liner C2 | Engine and engine cooling |
| 2011 Thomas Built Buses Saf-T-Liner Mvp-Ef | Engine and engine cooling |
| 2011 Thomas Built Buses Saf-T-Liner Hdx | Engine and engine cooling |
| 2012 Thomas Built Buses Saf-T-Liner Hdx | Engine and engine cooling |
| 2012 Thomas Built Buses Saf-T-Liner C2 | Engine and engine cooling |
| Units affected | 1,825 |
The year and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific bus is included.
What's the safety risk?
If the exhaust inlet or outlet sections disconnect, hot exhaust gases can vent before the tailpipe, creating a fire risk. If both clamps fail, the DOC/DPF housing can detach and create a road hazard. Schedule service soon and avoid driving if you notice loose exhaust parts. Repair will be free at any franchised Thomas Built Buses dealer once available.
What should I do?
- Check your VIN to confirm your 2011-2012 Thomas Built Buses Saf-T-Liner Mvp-Ef, Saf-T-Liner C2, or Saf-T-Liner Hdx is included in this recall.
- Wait for the recall notice if your VIN is included, then contact a franchised Thomas Built Buses dealer or authorized Cummins dealer about the free repair.
- Reference recall number 11V480 when you call, and ask whether the V-band clamp and T-bolt repair is ready for your bus.
- Avoid operating the bus until the loose exhaust clamp is repaired, since a failed clamp lets hot exhaust vent near the DOC/DPF housing.
- Bring the recall notice and any service records to the repair visit.
What happens at the repair
The recall record says the safety recall began on October 10, 2011, and repairs are handled by authorized Cummins dealers. At the dealer, the technician addresses the V-band clamp assembly that connects the diesel oxidation catalyst and diesel particulate filter cone sections. The work focuses on the clamp and T-bolt connection so the inlet or outlet sections stay secured to the DOC and DPF housing. Parts and labor are covered by the recall once the repair is available through the authorized repair channel.
Timeline
| September 21, 2011 | NHTSA published the recall |
|---|---|
| October 10, 2011 | Owner notification mailed |
Frequently asked questions
What is recall 11V480?
Recall 11V480 covers 1,825 2011-2012 Thomas Built Buses Saf-T-Liner Mvp-Ef, Saf-T-Liner C2, and Saf-T-Liner Hdx school buses with Cummins ISX or ISL diesel engines. The V-band clamp T-bolt can fracture, loosen the exhaust connection, and allow hot exhaust gases to escape.
What should I do if my 2011-2012 Thomas Built Buses Saf-T-Liner Mvp-Ef, Saf-T-Liner C2, or Saf-T-Liner Hdx is on this recall?
Check your VIN to confirm your specific school bus is included in recall 11V480. If it is, contact Thomas Built Buses or Cummins service support and schedule the V-band clamp repair with an authorized Cummins dealer. Reference recall 11V480 when you call.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost, and this recall says repairs are performed by authorized Cummins dealers free of charge. Parts and labor are covered for included buses.
What is the safety risk?
The safety risk is fire and road debris. If the exhaust inlet or outlet sections disconnect, hot exhaust gases can vent before the tailpipe and create a combustion or fire risk. If both clamps fail, the DOC or DPF housing can detach and create a road hazard.
What if I bought this Thomas Built Buses school bus used?
The free recall repair still applies. Recall eligibility follows the VIN, not the first owner. Check your VIN to confirm whether this specific bus is included, then give recall 11V480 to the service desk when you schedule the repair.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/11V480000 |
|---|---|
| Thomas Built Buses customer service | 1-812-377-5000 |
| NHTSA recall # | 11V480 |
| NHTSA recall # (full) | 11V480000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Defect / Noncompliance Notice (PDF) (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on June 2, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →