Diesel engines produce nitrogen oxide gases during combustion that must be treated before leaving the exhaust system. The Cummins B6.7, L9 SCR 2018–2021: OEM 5418654 is a Selective Catalytic Reduction (SCR) assembly designed to reduce these emissions by supporting the chemical reaction that converts nitrogen oxides into safer compounds within the exhaust stream.
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Designed for Cummins B6.7 and L9 engines from 2018 to 2021, the OEM 5418654 SCR fits directly into the factory exhaust aftertreatment system.
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The catalyst chamber allows diesel exhaust fluid to mix with exhaust gases so nitrogen oxide emissions can be treated.
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As gases pass through the catalyst substrate, chemical reactions transform harmful NOx gases into nitrogen and water vapor.
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The internal honeycomb-style structure increases the surface area where emission-reducing reactions take place.
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A properly functioning OEM 5418654 SCR assembly supports stable readings from NOx sensors placed before and after the catalyst.
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The SCR works together with the DEF system, which injects a urea-based fluid into the exhaust stream to assist with emission reduction.
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The durable housing is designed to tolerate continuous exposure to high exhaust temperatures during heavy-duty truck operation.
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Replacing a restricted or worn SCR unit helps restore proper exhaust flow and consistent emission system function.
The Cummins B6.7, L9 SCR 2018–2021: OEM 5418654 from Tamerx Diesel Parts provides a dependable replacement solution for maintaining proper aftertreatment operation. With the correct SCR assembly installed, the emission system can continue processing exhaust gases effectively while supporting reliable engine operation.











































