Fits 2011-2016 GM 6.6L LML Duramax
Kit Contains:
(2) Cylinders 1 and 8 (GM Cross Reference Part # 12670468)
(2) Cylinders 2 and 7 (GM Cross Reference Part # 12670460)
(2) Cylinders 3 and 6 (GM Cross Reference Part # 12670469)
(2) Cylinders 4 and 5 (GM Cross Reference Part # 12670471)
Complete 8-line replacement kit – superior corrosion protection – direct OEM fit
The NorCal Diesel Performance High Pressure Injector Line Kit is a complete drop-in replacement for the high pressure injector lines on 2011–2016 GM 6.6L LML Duramax trucks. This 8-line kit restores fuel system integrity, eliminates leaks, and protects new injectors and pumps by replacing old, corroded, or contaminated lines with high-quality, corrosion-resistant replacements.
Includes all eight injector feed lines in four matched pairs:
Cylinders 1 & 8 – replaces GM 12670468
Cylinders 2 & 7 – replaces GM 12670460
Cylinders 3 & 6 – replaces GM 12670469
Cylinders 4 & 5 – replaces GM 12670471
Cross-reference GM numbers: 12670468, 12670460, 12670469, 12670471, 98063063, 98063064, 98063065, 98063066.
2011–2016 Chevy/GMC 2500HD & 3500HD (Silverado/Sierra)
2011–2016 Express/Savana 2500/3500/4500 with 6.6L LML Duramax (VIN 8)
Fuel system: Bosch CP4.2 high pressure common rail
High pressure lines on LML Duramax engines are wear items. They live in a 30,000+ PSI, high-heat environment and see the same pressure pulses and thermal cycles as the injectors and pump.
Replace all eight lines when:
Replacing injectors
Repairing or replacing a CP4 pump (especially after metal contamination)
Addressing external leaks, corrosion, or recurring fuel pressure codes
As preventive maintenance around 100,000 miles or 8–10 years
Reusing old lines risks:
Microscopic metal contamination destroying new injectors
Poor sealing at previously torqued fittings
Repeat leaks and come-backs that cost far more in labor than a complete kit
Complete 8-line kit – everything needed in one box
High-strength steel tubing rated beyond 30,000 PSI operating pressure
Enhanced corrosion resistance via zinc plating/protective coating
Direct OEM-equivalent fitment – correct routing and cylinder pairing
Helps protect new injectors and pumps from contamination damage
Material: High-strength steel with protective coating
Pressure rating: Exceeds 30,000 PSI (2,000 bar)
Sealing: Metal-to-metal taper (no sealant required)
Torque spec: 30 lb-ft (41 N·m) at injector and rail ends
Manufacturing: ISO 9001:2015 certified facility, tested to SAE J1958 standards
Typical professional install time: 3–5 hours
DIY owners should plan 4–6 hours with proper tools and torque wrench
Cleanliness is critical – keep all ports capped and work area clean
Do not use thread sealant on high pressure fittings
Properly bleed and prime the fuel system after installation
Recheck for leaks at idle and again at full operating temperature
2-year manufacturer warranty
Designed and supported by NorCal Diesel Performance
If you are replacing injectors or addressing CP4 issues on an LML, this kit is the correct way to restore the high-pressure side of the system and protect your investment in new components.
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