Home » 2017-2025 6.6L Chevy GMC Duramax L5P diesel EGR Valve Cooler Delete kit

Compatibility: 2017–2025 Chevrolet / GMC Duramax 6.6L L5P

Product: Full EGR Valve & Cooler Delete Performance Kit

LEGAL DISCLAIMER & COMPLIANCE

OFF-ROAD USE ONLY: This high-performance racing component is engineered exclusively for competition or sanctioned off-road use. It does not comply with federal or local emissions laws for highway operation. Installation on any vehicle registered for public roads is strictly prohibited. The end-user assumes all legal liability and risk associated with the installation and use of this product.

PHASE 1: INITIAL DISASSEMBLY & FLUID DRAINAGE

Step 1: Electrical & Access Disconnect the negative cables from both batteries. Remove the passenger-side inner fender liner to access the engine bay components.

Step 2: Coolant Drainage Locate the plastic threaded drain plug on the lower corner of the passenger-side radiator.

  • Tech Tip: The coolant reservoir cap is reverse-threaded. Do not remove the cap immediately to prevent pressurized spraying; loosen it slowly to allow the system to drain into a catch bucket at a controlled rate.

Step 3: Intake & Heat Shielding Remove the air intake box and induction pipe. Locate the EGR "hot side" pipe (connecting the valve to the cooler and Y-bridge). Remove its heat shield and the six (6) 13mm mounting bolts to extract the pipeline.

Step 4: Turbo Horn & PCV System Remove the turbocharger intake horn. To disconnect the PCV hose, use a flat-head screwdriver or pry tool to gently release the non-removable metal band from the horn. Note: Leave the PCV hose connected to the PCV box on the driver-side valve cover.

PHASE 2: TOP-END COMPONENT REMOVAL

Step 5: Coolant Hardlines Remove the small-diameter aluminum coolant line assembly bolted to the top of the Y-bridge. At this stage, remove only the aluminum hardline; leave the connecting rubber hoses in place.

Step 6: Intercooler Pipe Disconnection Remove the 13mm bolt from the cold-side pipe support bracket. Disconnect the plastic intercooler pipe from the Y-bridge/throttle body by rotating it clockwise and pulling downward.

Step 7: Harness Isolation Disconnect the wiring harness sitting atop the Y-bridge. Carefully remove all "Christmas tree" style clips and connectors, including those on the throttle blade, to clear the path for bridge removal.

Step 8: AC Compressor Positioning Release the serpentine belt tension using a 1/2” ratchet on the tensioner. Unbolt the AC Compressor and set it aside (complete removal of the compressor or belt is not required). Remove the bale connector bracket from the top of the compressor.

Step 9: Y-Bridge Extraction Using a 1/4” drive 10mm socket with a long extension, remove the eight (8) bolts securing the Y-bridge to the intake runners.

  • Critical: Once the bridge is removed, immediately stuff clean shop rags into the open intake runner ports to prevent debris from entering the engine.

PHASE 3: EGR SYSTEM REMOVAL & BLOCK-OFF

Step 10: Hot Side Pipe Removal Remove the heat shield from the shorter EGR hot side pipe (connecting the upper and lower valves). Remove the four (4) 13mm bolts to extract the pipe.

Step 11: Lower EGR Valve Removal Disconnect all coolant hoses from the upper EGR valve. Remove the four (4) 13mm bolts/nuts securing the lower EGR valve to the exhaust manifold and remove the unit.

Step 12: Manifold Block-Off Install the supplied Steel Manifold Block-Off Plate using a new gasket. Reuse two factory studs and nuts; torque to 25 ft-lbs.

Step 13: Coolant Housing Modification Remove the two large-diameter steel coolant pipes from the thermostat crossover housing.

  • Note: Retain the large spring clamp near the turbo for reuse.

Step 14: Thermostat Housing Plug Apply grease to the O-ring of the supplied Billet Plug. Insert it into the coolant port on the thermostat housing (in front of the passenger intake port) and secure it with the OEM bolt.

Step 15: Cooler Extraction Disconnect the small coolant line from the turbo to the EGR cooler. Remove the five (5) 13mm bolts securing the EGR cooler to the engine and remove the entire assembly.

PHASE 4: COOLANT SYSTEM REROUTING

Step 16-19: Heater Core Hose Integration

  1. Remove the aluminum coolant hardline connecting the firewall heater core hose to the lower radiator hose.

  2. Install the provided 20” Long 5/8” Hose Assembly. Use the brass barb fitting to connect to the OEM bottom hose with the factory spring clamp.

  3. Push the upper end of the new hose onto the heater core fitting until the quick-connect clips lock into place.

Step 20-21: Urea Injector Bypass Disconnect the rubber hoses from the Urea Injector (front exhaust elbow). Insert the 5/16” Barbed Plug into the rubber hose connected to the main lower radiator hose. Secure with the provided clamp and zip-tie the line away from heat sources.

PHASE 5: TURBOCHARGER & SCR REMOVAL

Step 22-24: Turbo & SCR Prep Remove the T-bolt clamp from the hot-side intercooler boot. Remove the PCV hardline bolts from the back of the turbo compressor cover. Remove the SCR heat shields and the NOX sensor. Loosen the V-band clamps at the downpipe and turbo housing.

Step 25-27: Turbo Extraction Disconnect the turbo oil drain line (save the non-replaceable gasket). Remove the coolant feed and return hardlines from the turbo center section. Remove the four (4) 15mm bolts securing the turbo to the pedestal. Lift out the turbocharger, followed by the SCR unit.

PHASE 6: DOWNPIPE INSTALLATION

Step 28-30: OEM Downpipe Removal Disconnect the downpipe from the exhaust front pipe. Remove the support brackets and pull the downpipe out through the bottom. Transfer the metal sealing ring to the new downpipe.

Step 31-32: Performance Downpipe Fitment Install the new 3.5” Downpipe from the top side. Position the support tab on the engine but keep the bolts loose for final alignment.

PHASE 7: FINAL REASSEMBLY

Step 33-37: Turbo Reinstallation

  1. Install a new Turbo Pedestal Gasket. Reinstall the turbocharger (Torque: 43 ft-lbs).

  2. Tighten oil drain bolts (Torque: 89 in-lbs).

  3. Connect the downpipe to the turbo using the OEM V-band clamp.

  4. Reinstall the oil feed line (Torque: 89 in-lbs) and PCV line fitting.

Step 38-41: Final Coolant Plumbing Reinstall turbo coolant lines. Flip the return line (upper hardline) upside down from its original position for proper routing. Install the 1/4” Silicone Cap to block the unnecessary port on the lower supply line. Connect the remaining heater and turbo coolant lines using the provided 15” and 3/8” hoses as specified.

Step 42-45: Intake & Finishing

  1. Install the Bridge Block-Off Plate with the provided gasket (Torque: 25 ft-lbs).

  2. Reinstall the Y-bridge (Torque: 89 in-lbs).

  3. Reinstall the AC Compressor, serpentine belt, and wiring harness.

  4. Reinstall the turbo intake horn and CAC pipe.

Step 46: 9th Injector Block-Off Locate the 9th injector on the passenger frame rail. Disconnect the hardline at the fuel cooler. Install the Billet Block-Off Plug and secure it with the yellow factory clip.

POST-INSTALLATION ADVISORY

  • ECM Tuning: This hardware modification requires a compatible Race Tune to prevent "Limp Mode" and engine codes.

  • Fluid Check: Refill engine coolant and bleed the air from the system.

  • Inspection: Re-torque all hardware after the first 100 miles.