{"product_id":"cummins-isx15-cylinder-head-4374091","title":"Cummins ISX15 Cylinder Head, 4374091 | X15 SOHC Loaded, New","description":"\u003ch2\u003e\u003cstrong\u003eBrand New Cummins ISX15 \/ X15 Single Overhead Cam Fully Loaded Cylinder Head — 4374091\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eEngineered for reliability | Backed by 1-year warranty\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThis is a \u003cstrong\u003ebrand new cylinder head\u003c\/strong\u003e — not remanufactured, not refurbished — for Cummins \u003cstrong\u003eISX15 and X15 single overhead cam\u003c\/strong\u003e engines. Precision machined to meet or exceed OEM standards and fully loaded, it is the direct replacement for a cracked or worn factory head without the gamble of a reman core that already failed once.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eKey Features\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eBrand new casting\u003c\/strong\u003e — zero hours, not remanufactured or refurbished\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eFully loaded\u003c\/strong\u003e — valve train components installed and ready to bolt on\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003ePrecision machined\u003c\/strong\u003e for exact fit and performance\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eHigh-strength materials\u003c\/strong\u003e built for heavy-duty cycles\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003e1-year warranty\u003c\/strong\u003e — no core charge, no core return\u003c\/p\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eChoose Your Stage\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eStage 2 (Reinforced)\u003c\/strong\u003e — upgraded casting, standard valve package\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eStage 3 Loaded\u003c\/strong\u003e — Inconel intake \u0026amp; exhaust valves for high-heat, high-load duty\u003c\/p\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cp\u003e\u003cstrong\u003eStage 4 (Fire Rings)\u003c\/strong\u003e — for fire-ringed applications; made to order, estimated prep time 1–3 days\u003c\/p\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eFitment\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eCummins \u003cstrong\u003eISX15 and X15 single overhead cam (SOHC)\u003c\/strong\u003e engines. \u003cstrong\u003eNot for early dual-overhead-cam ISX applications\u003c\/strong\u003e — if you are unsure which you have, send us your engine serial number and we will confirm before you order.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eComplete the Job\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eISX head bolts are torque-to-yield and single-use — every head swap needs the \u003ca href=\"\/products\/cummins-isx-head-bolt-kit-3678506\"\u003e\u003cstrong\u003eISX \/ X15 Head Bolt Kit (3678506 \/ 3678804)\u003c\/strong\u003e\u003c\/a\u003e, one kit for every year 1999–2026, standard or cryo treated.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoing the head only?\u003c\/strong\u003e Add the \u003ca href=\"\/products\/5406187-cummins-isx15-head-gasket-set-4376104-2881767\"\u003e\u003cstrong\u003eISX15 Head Gasket Set (4376104)\u003c\/strong\u003e\u003c\/a\u003e or \u003ca href=\"\/products\/5406187-cummins-x15-head-gasket-set-upper-gasket-set\"\u003e\u003cstrong\u003eX15 Upper Gasket Set (5406187)\u003c\/strong\u003e\u003c\/a\u003e.\u003cbr\u003e\u003cstrong\u003eDoing a full in-frame overhaul?\u003c\/strong\u003e Skip the gasket set — your overhaul kit already includes it.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eOEM Cross Reference Numbers\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e3686432 | 3686434 | 3686660 | 3686774 | 3686880 | 3686881 | 3687607 | 3688761 | 3688800 | 4298235 | 4298236 | 4298237 | 4298238 | 4356434 | 4386009 | 5394197 | 5394198 | 79438920 | 79457900 | 79469386 | 79527893 | 79575425 | 4374091\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eNote: please confirm compatibility with your engine serial number prior to purchase. Contact us if you need assistance.\u003c\/em\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePLEASE NOTE: FIRE RING HEADS ARE MADE TO ORDER, ESTIMATED PREP TIME IS 1-3 DAYS.\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs this a new head or a remanufactured head?\u003c\/strong\u003e\u003cbr\u003eNew. A remanufactured head starts as a used core that has already been through hundreds of thousands of heat cycles. This casting has zero hours on it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill this fit my ISX?\u003c\/strong\u003e\u003cbr\u003eIt fits ISX15 and X15 single overhead cam engines. Early ISX engines with dual overhead cams use a different head — send us your ESN and we will verify.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I know if my ISX head is cracked?\u003c\/strong\u003e\u003cbr\u003eCoolant loss with no external leak, white smoke on cold start, combustion gases in the coolant, and overheating that a thermostat does not fix. A pressure test confirms it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo I need to return my old head?\u003c\/strong\u003e\u003cbr\u003eNo — no core charge, no core return required.\u003c\/p\u003e","brand":"TTM Diesel","offers":[{"title":"STAGE 2 (REINFORCED)","offer_id":47259159724244,"sku":"4374091","price":3400.0,"currency_code":"USD","in_stock":true},{"title":"STAGE 3 LOADED (INT \u0026 EXH INCONNEL VALVES)","offer_id":47259171553492,"sku":"4374091-3","price":4000.0,"currency_code":"USD","in_stock":true},{"title":"STAGE 4 (W\/FIRE RINGS)","offer_id":47259159757012,"sku":"4374091-FR","price":4200.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0671\/9927\/1124\/products\/CUMMINSISXSOHCHEAD2_600x1_a65b6145-15a7-469d-b946-2074f7fc23a8.png?v=1741700705","url":"https:\/\/ttmdiesel.com\/products\/cummins-isx15-cylinder-head-4374091","provider":"TTM Diesel","version":"1.0","type":"link"}