Recall 21V327 affects 1,262 2018-2021 Thomas Built Buses Saf-T-Liner Hdx school buses for a fuel rail leak risk. Free repair once Thomas Built Buses opens it.
Thomas Built Buses is recalling 1,262 2018-2021 Saf-T-Liner Hdx school buses under recall 21V327 because the sealing washer in the high pressure fuel rail assembly can fail to seat correctly, allowing fuel to leak. A fuel leak near an ignition source raises the risk of a fire, and the dealer repair will be free once Thomas Built Buses opens the remedy.
Does this recall apply to your specific vehicle?
The official, free per-VIN recall check is run by NHTSA. Enter your VIN and we'll forward you directly — and add you to a free watchlist so you hear about new recalls for your vehicle.
Check my VIN at NHTSARecallNotify doesn't check your VIN — NHTSA's official tool does. We use your email only to alert you to new recalls.
Watch this vehicle for recalls
Add it to your free watchlist and we will alert you as new federal recalls are posted for your year, make and model. New-recall alerts are rolling out now.
You are on the watchlist.
We will email you as new federal recalls are posted for your vehicle.
What's wrong?
The high pressure fuel rail on the 2018-2021 Thomas Built Buses Saf-T-Liner Hdx is part of the Cummins common rail diesel fuel system. The rail holds diesel fuel at very high pressure and feeds it to each injector at the right moment for combustion. A small sealing washer sits in each pilot bore hole on the rail to keep that pressurized fuel inside the assembly.
On affected buses, the sealing washer does not seat correctly in the pilot bore hole. With the washer out of position, the joint cannot hold the high pressure, and diesel fuel leaks from the rail assembly. Leaking fuel near a hot engine raises the risk of a fire, which is especially serious in a school bus carrying children.
There is no warning sign before failure. Owners and drivers will not see a dashboard alert or feel a change in how the bus drives before fuel begins to escape from the rail.
Who's affected?
Covers the Saf-T-Liner HDX across four consecutive model years (2018-2021), all built with the same high-pressure fuel rail assembly.
| 2021 Thomas Built Buses Saf-T-Liner Hdx | fuel system |
|---|---|
| 2020 Thomas Built Buses Saf-T-Liner Hdx | fuel system |
| 2018 Thomas Built Buses Saf-T-Liner Hdx | fuel system |
| 2019 Thomas Built Buses Saf-T-Liner Hdx | fuel system |
| Units affected | 1,262 |
| Field incidents | NHTSA has logged no field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether your specific bus is included in this recall.
What's the safety risk?
A fuel leak near an ignition source raises the risk of an underhood or undercarriage fire. Watch for a fuel smell around the engine bay, visible wet spots near the fuel rail or lines, or a fuel gauge dropping faster than usual, and stop driving the bus if any of those show up. Park away from buildings until the work is done. Repair will be free at any franchised Thomas Built Buses dealer once available.
What should I do?
- Check your VIN to confirm your 2018-2021 Thomas Built Buses Saf-T-Liner Hdx is included in this recall.
- Wait for the final remedy notification from Thomas Built Buses. The fuel-rail and fuel-line replacement is still under development.
- Park the bus away from buildings and other vehicles until the repair is complete, since a fuel leak near an ignition source raises the fire risk.
- Watch for fuel odors or visible leaks around the engine. If you notice either, stop using the bus and call the dealer.
- Contact a franchised Thomas Built Buses dealer once the final remedy opens to schedule the free fuel-rail and fuel-line replacement that fixes the leaking high-pressure fuel rail.
- Call Thomas Built Buses customer service at 1-800-547-0712 with questions and reference recall number 21V327 (DTNA recall FL-886) when you call.
What happens at the repair
The final dealer repair is still under development. Cummins is preparing the remedy, which will be performed at Cummins authorized service facilities. Once the repair opens, technicians will replace the fuel rail and fuel lines, with parts and labor free under the recall. Reimbursement details have not been published yet. Daimler Trucks North America will submit the reimbursement plan as a supplemental report when it is available. If you have questions about your bus in the meantime, contact DTNA customer service at 1-800-547-0712 and reference recall FL-886.
Timeline
| May 7, 2021 | NHTSA published the recall |
|---|---|
| July 5, 2021 | Dealer notification began |
| July 5, 2021 | Dealer notification ended |
| July 5, 2021 | Interim owner notification (was planned for this date) |
| October 29, 2021 | Owner notification mailed |
Frequently asked questions
What is recall 21V327?
Recall 21V327 covers 1,262 2018-2021 Thomas Built Buses Saf-T-Liner HDX school buses with a fuel rail sealing washer that can fail to seat correctly in the pilot bore holes. The defect allows the high-pressure fuel rail to leak, and a fuel leak near an ignition source raises the risk of a fire.
What should I do if my 2018-2021 Thomas Built Buses Saf-T-Liner Hdx is on this recall?
Check your VIN to confirm your specific bus is included in recall 21V327. If it is, contact a Thomas Built Buses dealer to schedule the fuel rail and fuel line replacement once the final remedy opens. Reference recall 21V327 when you call, or reach DTNA customer service at 1-800-547-0712.
Is the recall repair free?
Yes. Federal recall law requires manufacturers to repair the defect at no cost to the owner. Dealers will replace the fuel rail and fuel lines free of charge once the final remedy is released. Parts and labor are covered under the recall.
What is the safety risk with the fuel rail on these buses?
If the sealing washer does not seat correctly, the high-pressure fuel rail can leak. Leaking diesel fuel near an ignition source raises the risk of an underhood fire. Park the bus away from structures if you smell fuel, and contact a Thomas Built Buses dealer to confirm next steps.
When will the repair for recall 21V327 be available?
The final remedy is still under development. Interim owner notification letters were mailed on June 21, 2021, and a second notice will be sent once the fuel rail and fuel line replacement parts are ready. Check your VIN to confirm inclusion, then contact a Thomas Built Buses dealer when the final remedy opens.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/21V327000 |
|---|---|
| Thomas Built Buses customer service | 1-800-547-0712 |
| NHTSA recall # | 21V327 |
| NHTSA recall # (full) | 21V327000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Misc. Document (PDF)
- Download Recall Document (PDF) (PDF)
- Download Owner Notification Letter (PDF)
- Download Owner Notice (PDF)
- Download Recall Report (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 24, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →