In the world of modern diesel engines, your aftertreatment system is only as strong as its weakest link—and often that link is the DEF (Diesel Exhaust Fluid) head. For Stewart & Stevenson units employing the Cummins ISL engine, the OEM 24300154-11 DEF Head Unit (Tamerx part no. 4310-18-16) is a critical component that ensures accurate sensing, fluid dosing, and compliance with emissions standards. When this head fails or drifts out of spec, you could face warning codes, engine derates, or worse—a breakdown at the worst possible moment.
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Senses DEF fluid parameters—level, temperature, and urea/quality—and relays precise data to the engine control module
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Controls dosing of DEF into the exhaust to enable the SCR (Selective Catalytic Reduction) system to reduce NOx emissions
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Matches the OEM 24300154-11 specification for Stewart & Stevenson Cummins ISL applications
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Helps prevent system fault codes, emissions warnings, and engine derating triggered by incorrect sensor readings
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Constructed to withstand vibration, thermal cycling, and exposure to corrosive DEF chemicals
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Relatively user-friendly replacement design to cut down on downtime
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Backed by Tamerx’s one million mile / one year warranty when installed correctly
Don’t let a degraded or failing DEF head compromise your emissions system or force unexpected service stops. By installing the OEM 24300154-11 Stewart & Stevenson Cummins ISL DEF Head Unit, you restore accurate sensing and dosing, maintain system integrity, and safeguard your vehicle against avoidable emissions issues. Make this component a maintenance priority and keep your engine running clean and reliable.



























































































































































































































































































