Service bulletins for the 2021 Western Star 4900
A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.
117 on file from NHTSA, as of 2026-10-19.
By type
By component
Only bulletins with component: Engine are shown. Show all
| D20M3 | 2020-06-26. Service bulletin. ENGINE AND ENGINE COOLING. Detroit Field Service campaign for DETROIT Export DD15 and DD13 Valve Lash Adjustment, Throttle Connector O-ring, and TC Air Line Spacer Installation. |
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| WI20-009 | 2020-06-13. Service bulletin. ENGINE AND ENGINE COOLING. Warranty Information Letter for a Warranty Service Replacement Engine Program Clarification. Detroit established the Warranty Service Replacement Engine Program to support an unrepairable catastrophic engine failure due to manufacturing defect. To improve understanding and utilization of the program, DTNA is clarifying eligibility and engine returns. |
| WI20-004 | 2020-04-23. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. Warranty Information Letter for Warranty Long Block Program Change. The Detroit Reman Long Block Program has expanded. The expansion reduces complexity in ordering reman engines and promotes stocking reman engines to meet uptime commitments. |
| SS1034681 | 2020-03-24. Service bulletin. ENGINE AND ENGINE COOLING:COOLING SYSTEM:RADIATOR ASSEMBLY. Service Solution for Lower Radiator Pipe Rubbing on X15 Cummins engine. Due to limited clearance, the lower radiator pipe may rub on the engine block and lower radiator hose may rub on the front engine support causing radiator coolant leakage on Cummins X15 installations. |
| 20CSA-04 | 2020-03-22. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. Customer Service Announcement saying that Service Pack (SP) 3 for DiagnosticLink® 8.11 Standard and Professional will be available for download from the Detroit Diesel server. |
| 20TS-02 | 2020-03-06. Service bulletin. ENGINE AND ENGINE COOLING. Technical Service Letter for DD Platform Heavy Duty, Metal in the Oil and Oil Filter. Some engine component failures can cause metallic debris to circulate throughout the engine lubrication system. Although the oil filter will capture most of this debris, some debris may enter the clean side of the lubrication system during oil filter bypass. Detroit has created a lubrication system cleaning and flushing procedure to address this problem. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.