2020-2024 3.0L Duramax LM2 EGR & DPF Instructions

Before starting, please confirm the truck is an LM2 3.0L Duramax application and that the correct tuning is available for the vehicle. We also recommend flashing the truck before removing any factory emissions hardware.

Kit Contents

The kit should include:

• Blue silicone coolant bypass hose
• Two blue silicone caps
• Ground cable
• Two EGR block-off plates
• Aluminum intake plug
• EGR gaskets

Before Installation

1. Park the truck on level ground.
2. Allow the engine to cool completely.
3. Disconnect the batteries.
4. Drain enough coolant so the level is below the EGR cooler/coolant hose area.
5. Remove the engine cover and intake/charge piping as needed for access.
6. Remove any heat shields or brackets blocking access to the EGR cooler, EGR valve, and related piping.
7. Take photos before removing hoses, brackets, or connectors so everything can be referenced during reassembly.

Installation Procedure

1. Remove the factory EGR coolant hoses
2. Place a drain pan underneath the work area. Remove the coolant hoses connected to the EGR cooler. Expect some coolant to spill. Inspect the factory coolant ports and clean off any leftover hose material or debris.
3. Remove the EGR valve and cooler assembly
4. Unplug the EGR valve electrical connector. Remove the bolts securing the EGR valve, EGR cooler, cooler pipe, and related brackets. Carefully remove the EGR cooler and valve assembly from the engine bay.
5. Be careful not to pry against plastic intake parts, fuel lines, wiring harnesses, or coolant hard lines.
6. Install the aluminum intake plug
7. Clean the intake-side EGR opening. Remove any soot or gasket material, making sure no debris falls into the intake. Install the supplied aluminum intake plug into the EGR/intake opening. Make sure it seats evenly and fully. Secure it using the factory or supplied hardware, depending on the kit design.
8. Do not overtighten aluminum components.
9. Install the EGR block-off plates
10. Clean both sealing surfaces where the EGR cooler/valve assembly was removed. Install the supplied gaskets where applicable. Install the smaller and larger block-off plates in the appropriate EGR locations.
11. Start all bolts by hand first, then tighten evenly in stages. Use OEM torque specs where available. If torque specs are not available, tighten the plates snugly and evenly without bending the plates or crushing the gasket.
12. Install the blue coolant bypass hose
13. Identify the two coolant ports that previously fed and returned coolant through the EGR cooler. Install the large blue silicone bypass hose between those two ports.
14. Make sure the hose is fully seated, not kinked, and routed away from sharp edges, exhaust heat, belts, or pulleys. Secure the hose using the factory clamps or suitable replacement clamps.
15. Install the two blue silicone caps
16. Locate any unused coolant ports left open after removing the factory EGR coolant routing. Install the supplied silicone caps fully onto those ports and secure them with clamps.
17. Do not leave any coolant port open or loosely capped.
18. Install the ground cable
19. If the factory EGR or exhaust valve assembly had a ground strap or ground point that was removed, install the supplied ground cable to restore a proper ground path.
20. Attach one end to a clean engine ground point and the other end to the corresponding chassis/body/bracket ground location. Make sure the cable has enough slack for engine movement and is routed away from heat, sharp edges, and moving parts.
21. Reinstall surrounding components
22. Reinstall any intake piping, charge piping, heat shields, brackets, and covers that were removed for access. Secure all wiring harnesses and connectors away from heat or moving components.
23. Refill and bleed the coolant system
24. Refill the cooling system with the correct coolant. Reconnect the batteries. Start the truck and allow it to idle while monitoring coolant level and temperature. Turn the heater on high and top off the coolant as needed while air works out of the system.
25. Check for leaks and proper operation

While the truck is running, inspect the following areas:

• Blue coolant bypass hose
• Blue coolant caps
• EGR block-off plates
• Aluminum intake plug
• Any coolant fittings or ports that were disturbed
• Any wiring or hoses near exhaust heat

Watch for coolant leaks, exhaust soot marks, hissing, abnormal idle, or warning lights.

11. Final inspection

After the first heat cycle, shut the truck off and allow it to cool. Recheck coolant level, clamps, block-off plates, and all accessible hardware. Road test the truck briefly, then inspect again for leaks or soot tracking around the block-off plates.

Important Notes

• The truck must have proper emissions-off tuning loaded before operating with the EGR components removed or blocked.
• Flash the vehicle before removing hard parts whenever possible.
• Use a battery charger/maintainer while flashing.
• Keep all factory parts until the truck has been fully tested.
• If any coolant leak, exhaust leak, or electrical issue is present after installation, stop and inspect before continuing to drive the truck.

Professional installation is recommended if the installer is not familiar with LM2 EGR and coolant routing.