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: Cooling system are shown. Show all
| 18SP736 | 2020-10-01. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:BELTS AND ASSOCIATED PULLEYS; ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN. Detroit Diesel Special Publication informing about Heavy Duty Friction Style Belt Tensioner Kit. This heavy duty friction style belt tensioner kit contains the belt tensioner and two M10 bolts to correctly pin the friction style belt tensioner. The M10x80mm bolt is used to pin the engine cooling fan drive arm. The M10x50mm bolt is used to pin the engine accessory drive arm. |
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| 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. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.