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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

Bulletins, newest first
PB-47-900-WST2026-07-06. Service bulletin. FUEL/PROPULSION SYSTEM. Parts Bulletin for Fluorosilicone Fuel Tank Cap Seals
CXA 03_26_Surge Tank2026-04-02. Other. ENGINE. CX Advocate for discolored coolant surge tanks (24CSA-20)
CXA_10_25_Conmet Oil Pan2025-11-05. Other. ENGINE. CX Advocate for ConMet Oil Pan Insert Additional Issues
24CSA-19Rev2025-09-02. Other. ENGINE. Revised Customer Service Annoucement for No Trouble Found Heavy Duty Engine Product (HDEP) Oil Separator Leaks
CXA 3_25_NOx2025-04-02. Other. ENGINE. CX Advocate for NOx conversion low faults
CXA 2_25_NOx2025-03-04. Other. ENGINE. CX Advocate for NOx conversion low faults
CXA 1_16_NOx2025-01-29. Other. ENGINE. CX Advocate for NOx conversion low faults
SS1023366-Detroit2024-11-06. Other. ENGINE. Service Solution for Detroit Successful Regen Reference for GHG17 DD Engines
24CSA-202024-11-06. Service bulletin. ENGINE. Customer Service Annoucement for Discolored Coolant Surge Tank on Heavy Duty Engine Product (HDEP)
24CSA-192024-11-06. Other. ENGINE. Customer Service Annoucement for Heavy-Duty Engine Product (HDEP) Oil Separator Leaks
SS1023366-Detroit2024-10-04. Other. ENGINE. Service Solution for Detroit Successful Regen Reference for GHG17 DD Engines
CXA 8_24_Conmet Oil Pan2024-09-07. Other. ENGINE. CX Advocate for ConMet Oil Pan Insert Additional Failures
CXA 8_24_AutoElevate Disa2024-09-07. Other. ENGINE. CX Advocate for AutoElevate Disablement Gen5 Engines
CXA 8_24_AutoElevate and2024-09-07. Other. ENGINE. CX Advocate for benefits of Autoelevate and hydrocarbon faults
CXA 7_24_NOx2024-08-02. Other. ENGINE. CX Advocate for NOx conversion low faults. Update to CXA 6_24_NOx submission.
CXA 7_24_Conmet Oil Pan2024-08-02. Other. ENGINE. CX Advocate for ConMet Oil Pan Insert Additional Failures
CXA 7_24_AutoElevate Disa2024-08-02. Other. ENGINE. CX Advocate for AutoElevate Disablement Gen5 Engines
CXA 06_24_Clutch Bolts2024-07-09. Other. POWER TRAIN. CX Advocate communication for clutch bolts
CXA 06_24_NOx2024-07-09. Other. ENGINE. CX Advocate communication for NOx conversion low faults
VSWP Customer Letter2024-06-22. Other. ENGINE. Customer letter regarding variable speed water pump.
SS734-WST2024-06-05. Other. SUSPENSION. Service Solution for Thread Spring Pin Suspension Alignment & Installation
SS763-WST2024-06-05. Other. ENGINE. Service Solution for DEF Pump Wiring for Cummins CM2450 Engine Controller
TSB35-023-WST2024-06-05. Service bulletin. POWER TRAIN. Technical Service Bulletin for New Final Drive Over Heat Diagnostic
SS3144-FTL2024-05-07. Service bulletin. ENGINE AND ENGINE COOLING. Service Solution for DEF Pump Wiring for Cummins CM2450 Engine Controller
ICI24-0062024-03-06. Service bulletin. ENGINE AND ENGINE COOLING. Important Campaign Information letter for FL974 - Revised Bulletin & Population

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.