The Ultimate LML Duramax Delete Kit Installation Guide (Step-by-Step)

Prepare Passenger-Side Access for EGR and Up-Pipe Work

After the factory exhaust components are removed, additional access is required to reach the passenger-side EGR system and Up-pipe. Removing the passenger-side wheel and inner fender creates additional working space.

Remove the Passenger-Side Front Wheel

1. Secure the truck on a stable lifting surface.
2. Remove the passenger-side front wheel.
3. Store the lug nuts in a clean location.
4. Keep the wheel installation hardware organized for reassembly.

Remove the Passenger-Side Inner Fender

1. Remove the plastic retainers and screws holding the inner fender.
2. Pull the liner away from the wheel opening.
3. If the lower section remains attached by factory rivets, it can remain attached.
4. Move the liner upward and secure it out of the way.

If the truck is only receiving EGR block-off components and the factory Up-pipe remains installed, inner fender removal may not always be required. However, replacing the Up-pipe requires additional access.

Remove the DEF Fill Neck

Removing the DEF fill neck provides additional room around the passenger-side engine bay area.

1. Remove the intake ducting for access.
2. Disconnect any sensors attached to the intake system.
3. Remove the DEF fill neck mounting hardware.
4. Release the fill neck from its mounting location.
5. Pull the DEF fill neck out of the engine compartment.
6. Store all removed hardware for reinstallation if needed.

Raise the Passenger Side of the Cab for Additional Clearance

The source installation raises the passenger side of the cab slightly to create additional room around the EGR cooler and Up-pipe area. Only a small amount of movement is required.

Loosen the Cab Mounts

1. Locate the four passenger-side cab mounts.
2. Remove the passenger-side cab mount bolts.
3. Move to the driver side of the truck.
4. Loosen all four driver-side cab mount bolts.
5. Do not remove the driver-side bolts.

Before lifting the cab, inspect all nearby components including:

• Brake lines
• Electrical harnesses
• Ground cables
• Air conditioning lines
• Coolant hoses
• Steering components

Lift the Cab Carefully

1. Place a jack under a reinforced pinch weld area.
2. Use a wide wood or rubber pad between the jack and cab.
3. Raise the cab slowly.
4. Check all lines while lifting.
5. Lift only enough to create working clearance.
6. Install a solid support block between the cab and mount area.
7. Remove the jack pressure.

Never work under a cab supported only by a hydraulic jack. The cab must be mechanically supported before working underneath.

Drain the Engine Coolant

The coolant system must be drained before removing the EGR cooler and changing coolant routing.

1. Allow the engine to cool completely.
2. Place a drain pan below the coolant connection.
3. Locate the metal retaining clip.
4. Use a pick tool to release the clip.
5. Pull the coolant connection apart slightly.
6. Allow coolant to drain.
7. Once drained, reinstall the connection.
8. Lock the retaining clip back into position.
9. Verify the connection is secure.

Remove Intake Components for EGR Access

Additional intake components must be removed to access the EGR system and Up-pipe area.

Disconnect Both Battery Negative Terminals

1. Turn the ignition off.
2. Disconnect the negative terminal from the first battery.
3. Disconnect the negative terminal from the second battery.
4. Secure the cables away from the battery posts.

Remove the Turbo Silencer

1. Locate the turbo silencer housing.
2. Remove the two mounting bolts.
3. Lift the turbo silencer away.
4. Store the bolts with the component.

Remove the Aluminum Intake Pipe

1. Disconnect all electrical connectors attached to the intake pipe.
2. Remove connected hoses.
3. Release the locking ring.
4. Rotate the ring counterclockwise.
5. Remove the side mounting bolts.
6. Remove the lower bracket fasteners.
7. Release plastic wiring retainers.
8. Remove the aluminum intake pipe.

Remove the Black Plastic Turbo Inlet

1. Disconnect rear sensors.
2. Loosen the turbo inlet V-band clamp.
3. Remove the attached hose clamp.
4. Remove the plastic turbo inlet assembly.
5. Cover the turbo opening to prevent contamination.

Remove Remaining Intake Piping

1. Inspect nearby brackets that may interfere.
2. Loosen support brackets if necessary.
3. Remove the remaining intake pipe.
4. Protect all open intake ports.

Remove Turbo Heat Shield

1. Remove the heat shield mounting bolts.
2. Lift the shield out of the engine bay.
3. Store the shield for reinstallation.

Remove the Factory EGR System

The EGR system consists of the EGR valve, EGR cooler, coolant hoses, and related mounting hardware. Remove each component carefully and keep track of all original fasteners.

Remove the EGR Valve

1. Locate the EGR valve assembly.
2. Remove the four mounting bolts.
3. Support the valve during removal.
4. Remove the factory gasket.
5. Protect the intake opening from debris.

For additional EGR system information, see:

• What Is an EGR Valve?
• EGR Delete Full Overview

Disconnect the EGR Cooler

1. Remove the EGR cooler mounting hardware.
2. Disconnect the coolant hoses.
3. Disconnect the remaining brackets.
4. Remove the cooler from the engine bay.

Whenever possible, disconnect coolant hoses without cutting them. Preserving factory hose lengths makes coolant rerouting easier during reassembly.

Remove the Factory Up-Pipe

The factory Up-pipe connects the exhaust manifold area to the turbocharger side of the exhaust system. The replacement Up-pipe removes the original EGR branch design.

Remove the Coolant Pipe Blocking Up-Pipe Access

1. Locate the metal coolant pipe near the Up-pipe.
2. Remove the retaining bolt.
3. Move the pipe carefully.
4. Release the pipe from the O-ring connection.
5. Inspect the O-ring before reuse.

Remove the Six Up-Pipe Bolts

The Up-pipe uses three bolts on each end.

1. Apply penetrating lubricant to the bolts.
2. Allow time for the lubricant to work.
3. Loosen each bolt gradually.
4. Alternate between both ends.
5. Support the Up-pipe before removing the final bolt.
6. Remove the factory Up-pipe.
7. Remove old gaskets.

Handling Stubborn Up-Pipe Bolts

If a bolt becomes tight while removing:

1. Stop forcing the bolt.
2. Thread it back inward slightly.
3. Apply penetrating lubricant.
4. Work the bolt back and forth.
5. Repeat until it releases.

Breaking an Up-pipe bolt can create major repair work, especially if the bolt breaks near the turbocharger or exhaust manifold.

Install the Replacement Up-Pipe

Prepare the New Gaskets

1. Install the new gaskets in the correct orientation.
2. Confirm the locating features match the flange design.
3. Keep sealing surfaces clean.

Apply Anti-Seize to New Hardware

1. Clean the new bolts.
2. Apply a thin layer of high-temperature anti-seize.
3. Avoid applying compound to gasket surfaces.

Transfer the Factory Bracket

1. Remove the required bracket from the factory Up-pipe.
2. Clean the bracket mounting surface.
3. Modify clearance if required.
4. Install the bracket onto the replacement Up-pipe.

Install the New Up-Pipe

1. Position the new Up-pipe.
2. Install both gaskets.
3. Start all bolts by hand.
4. Confirm proper alignment.
5. Tighten both ends gradually.
6. Install the transferred bracket.
7. Verify the pipe is not under stress.

Always follow the torque specifications provided with the specific Up-pipe hardware. Do not apply torque values from unrelated applications.

Reroute the Coolant System After EGR Cooler Removal

After removing the factory EGR cooler, the original coolant routing must be modified. The goal is to maintain proper coolant circulation while removing the factory EGR cooler from the system.

The main coolant connections involved include:

• Firewall heater hose connection
• Coolant hose behind the turbo area
• Small coolant line near the engine front
• Original EGR cooler coolant connections

Prepare the Replacement Coolant Hose Assembly

1. Compare the supplied coolant hose with the factory routing.
2. Identify each connection point before cutting any hose.
3. Do not remove more material than necessary.
4. Confirm the hose length allows smooth routing without kinks.

Connect the Rear Coolant Hoses

1. Locate the factory hoses previously connected to the EGR cooler.
2. Route the replacement hose assembly between the required connection points.
3. Push each hose fully over the fitting.
4. Install hose clamps behind the fitting bead.
5. Verify the hoses are not twisted.

Connect the Small Coolant Line

1. Locate the smaller coolant branch line.
2. Connect the small replacement hose.
3. Secure the connection with the correct clamp.
4. Verify the hose cannot slide off the fitting.

Connect the Front Coolant Line

1. Route the remaining hose toward the front of the engine.
2. Connect it to the original coolant connection.
3. Secure the clamp.
4. Check clearance around belts and moving components.

Final Coolant Hose Routing Check

Before continuing, verify:

• No hose is kinked.
• No hose touches the Up-pipe.
• No hose contacts the turbocharger.
• No hose rubs against wiring or brackets.
• Engine movement will not pull the hoses tight.

Install Heat Protection

1. Reuse factory heat shields where possible.
2. Add heat protection near exhaust components.
3. Secure insulation away from moving parts.
4. Do not allow hoses to contact hot exhaust surfaces.

Reinstall the Intake System

After the Up-pipe and coolant routing are complete, reinstall the intake components removed earlier.

Install the Turbo Heat Shield

1. Position the factory heat shield.
2. Install the mounting bolts.
3. Confirm the shield does not contact the replacement Up-pipe.

Reconnect the PCV Hose

1. Inspect the PCV hose condition.
2. Remove the original crimp sleeve if required.
3. Install a suitable replacement hose clamp.
4. Secure the hose connection.

Install the Turbo Inlet

1. Inspect the O-ring condition.
2. Clean the sealing surface.
3. Install the turbo inlet assembly.
4. Reconnect the hose connections.
5. Tighten the V-band clamp.

Install the Aluminum Intake Pipe

1. Position the intake pipe into place.
2. Reconnect the mounting brackets.
3. Reconnect active sensors.
4. Reconnect power connections.
5. Install all original retainers.

Secure Unused Electrical Connectors

Any unused emissions-related connectors should be protected from moisture and secured away from heat.

1. Install connector caps where supplied.
2. Secure unused connectors with zip ties.
3. Keep wiring away from the turbocharger.
4. Prevent contact with exhaust components.
5. Do not leave wiring hanging near moving parts.

Lower the Cab and Complete Engine Bay Assembly

Lower the Cab Carefully

1. Inspect all hoses and wiring before lowering.
2. Confirm no tools remain under the cab.
3. Raise the cab slightly.
4. Remove the support block.
5. Lower the cab slowly.
6. Check for pinched hoses or wiring.
7. Allow the cab to fully settle onto the mounts.

Reinstall Cab Mount Hardware

1. Install all passenger-side cab mount bolts.
2. Install all previously loosened driver-side bolts.
3. Start all bolts by hand.
4. Confirm proper thread engagement.
5. Tighten according to factory specifications.

Never operate the vehicle with missing or loose cab mount hardware.

Reconnect Batteries

1. Confirm all electrical work is complete.
2. Reconnect both negative battery terminals.
3. Tighten battery connections.

Refill Coolant and Perform Initial Testing

Refill the Cooling System

1. Confirm all coolant connections are locked.
2. Check every hose clamp.
3. Add the correct coolant type.
4. Fill slowly to the correct level.
5. Do not reinstall the inner fender until leak checks are complete.

First Engine Start

1. Start the engine.
2. Allow it to idle.
3. Monitor coolant connections.
4. Check for leaks.
5. Listen for abnormal exhaust sounds.
6. Check for warning lights.

After reaching operating temperature, allow the truck to cool completely and recheck coolant level. Additional coolant may be required after air leaves the system.

Install the Replacement Exhaust System

The final exhaust installation depends on whether the truck uses replacement pipes or a complete exhaust system.

Option 1: Install DPF Replacement Pipes

When retaining the factory tailpipe, measure carefully before cutting any factory tubing.

Measure Before Cutting

1. Compare the replacement pipe with the factory exhaust.
2. Determine required overlap length.
3. Identify the correct straight section for cutting.
4. Mark the cutting location.
5. Measure again before cutting.

Cut the Factory Straight Pipe

1. Support the exhaust on both sides of the cut.
2. Verify no wiring or fuel lines are nearby.
3. Cut the marked straight section.
4. Deburr the pipe edge.
5. Clean all metal debris.

Install Replacement Pipe

1. Install the exhaust clamp over the pipe.
2. Slide the replacement pipe into position.
3. Confirm proper overlap.
4. Align the exhaust system.
5. Tighten the clamp after final positioning.

Option 2: Install Full 5-Inch Exhaust System

Install Front Exhaust Section

1. Position the front exhaust pipe.
2. Reconnect the factory support bracket.
3. Install the front connection hardware loosely.
4. Allow movement for final alignment.

Install Intermediate Exhaust Sections

1. Install the transition pipe.
2. Install exhaust clamps loosely.
3. Connect rubber hangers.
4. Continue installing rear sections.

Install Over-Axle Pipe

1. Position the over-axle section.
2. Clear the rear axle and suspension components.
3. Connect the hanger points.
4. Keep clamps loose during adjustment.

Install Tailpipe

1. Install the final tailpipe section.
2. Align the exhaust tip.
3. Confirm body clearance.
4. Confirm spare tire clearance.

Final Exhaust Alignment

Before tightening all clamps, verify:

• No contact with the frame.
• No contact with suspension components.
• No contact with brake lines.
• No contact with wiring.
• Proper exhaust hanger alignment.
• Correct tailpipe position.

Tighten Exhaust Connections

Tighten the exhaust system from the front toward the rear.

1. Front connection.
2. Support bracket.
3. Intermediate clamps.
4. Rear exhaust clamps.
5. Tailpipe clamp.

Final Inspection Checklist

Electrical

• All required connectors disconnected.
• Unused connectors protected.
• Harnesses secured away from heat.
• Battery connections tightened.

Cooling System

• All coolant hoses secure.
• No coolant leaks.
• Correct coolant level.
• Heat protection installed.

Up-Pipe and EGR System

• New Up-pipe installed correctly.
• New gaskets installed.
• Fasteners tightened properly.
• EGR block-off plate installed.

Exhaust

• All clamps tightened.
• No exhaust leaks.
• No rattles.
• No contact with chassis components.
• Exhaust hangers aligned.

Related Resources

• Best Delete Kits for LML Duramax Buying Guide
• Best EGR Delete Kit for LML Duramax
• Is Tuning Necessary After DPF Delete?
• DEF Delete Guide
• EZ Lynk Auto Agent Installation Guide