Installation Guide: High-Flow Intake for 5.9L Cummins (2003-2007)

4 min read
Installation Guide: High-Flow Intake for 5.9L Cummins (2003-2007)

 

This guide covers the removal of the restrictive stock airbox and the installation of a performance Cold Air Intake (CAI) on the 3rd Gen Dodge Ram 2500/3500.

  • Vehicle Fitment: 2003, 2004, 2005, 2006, 2007 Dodge Ram 2500/3500
  • Engine: 5.9L Cummins Turbo Diesel (24V Common Rail)
  • Difficulty: Beginner to Intermediate
  • Time Required: 60 Minutes

Tools Required

Don't get stuck halfway through. Gather these specific tools before you start:

  • Ratchet with extension
  • Sockets: 10mm (battery/airbox), 13mm (radiator shroud bolt), 7/16" or 11mm deep socket (for heavy-duty clamps)
  • Drivers: 5/16" Nut Driver or Flathead Screwdriver
  • Torx Driver: T-20 (required for some kits to mount the MAF/IAT adapter)
  • Panel Popper or Flathead (for removing wiring loom clips)
  • Clean rag (to cover turbo inlet)
⚠️ CRITICAL SAFETY NOTE:
The turbocharger on the 5.9L Cummins gets extremely hot. Allow the engine to cool for at least 2 hours before beginning this installation to avoid severe burns.

Part 1: Removing the Stock Air Intake

Step 1: Disconnect Batteries

This truck has a dual battery system. You must disconnect the Negative (-) terminals on BOTH driver and passenger side batteries using a 10mm socket. This prevents electrical shorts and resets the ECU to learn the new airflow data.

Step 2: Disconnect the IAT Sensor

Locate the Intake Air Temperature (IAT) sensor on the stock intake tube near the airbox.
CAUTION: This sensor locks in place.

  1. Slide the Red Locking Tab back to unlock it.
  2. Depress the tab and pull the harness plug off gently.
  3. Use a panel popper to remove the wire loom clip from the intake tube so the wire is free.

 

Step 3: Remove the Intake Tube

Loosen the hose clamp at the airbox lid and the hose clamp at the turbocharger inlet using a flathead screwdriver or 5/16" driver. Pull the tube off the turbo first, then detach it from the airbox. Remove the tube from the truck.

Step 4: Remove the Stock Airbox

The stock airbox is held in by one nut and rubber grommets.

  1. Locate the 10mm nut on the front-right side of the airbox (near the fender). Remove it.
  2. Lift the airbox straight up firmly. It is held in by grommets on the bottom—a good yank is usually required to pop it free.
  3. IMMEDIATELY place a clean rag over the open turbo inlet. Dropping a bolt or screw into the turbo will destroy your engine.

Part 2: Pre-Assembly & Sensor Transfer

🔧 The "Filter Minder" Trick:
Your stock airbox has a clear gauge called a "Filter Minder." Most aftermarket kits require you to reuse this. Remove it from the stock box by pushing it out from the inside or gently prying the rubber grommet. Do not pull by the plastic gauge itself or it may crack.

Step 5: Transfer the IAT Sensor

This is the most delicate part of the install.

  • Removal: The sensor is twist-locked. Grasp the sensor body, twist it counter-clockwise (about 1/4 turn), and pull it straight out. Be careful not to damage the plastic tip.
  • Installation: Install the supplied rubber grommet into your new intake tube. Lubricate the inside of the grommet with a little water or silicone spray. Push the IAT sensor gently into the new grommet until seated. Note the orientation (airflow direction).

Step 6: Prepare the Heat Shield

If your kit includes a heat shield (open box style):

  • Install the rubber edge trim around the top of the heat shield to seal against the hood.
  • Install the provided grommets into the bottom mounting points of the heat shield.

Part 3: Installing the New System

Step 7: Install Heat Shield & Mounting Points

Drop the new heat shield into the truck.
Crucial Step: Most kits utilize a mounting point on the radiator fan shroud. You will likely need to remove the top 13mm bolt on the fan shroud, align the new heat shield tab, and reinstall this bolt.
Push the bottom of the box firmly onto the factory mounting studs.

Step 8: Turbo Coupler & Tube

  1. Remove the rag from the turbo inlet.
  2. Install the straight silicone coupler onto the turbo inlet. Tighten the turbo-side clamp, but leave the tube-side clamp loose.
  3. Insert the new intake tube into the heat shield/filter side first, then slide it into the turbo coupler.
  4. Align the tube so it does not rub against the oil dipstick or A/C lines.

Step 9: Filter & Final Connections

  1. Install the large air filter onto the end of the intake tube inside the box. Tighten the large band clamp.
  2. Reconnect IAT: Plug the wiring harness back into the IAT sensor. Slide the red locking tab forward.
  3. Filter Minder: If reusing, press the Filter Minder grommet and gauge into the designated port on the new tube.

Part 4: Final Checks

  • Clearance Check: Ensure the tube is not touching the positive battery cable or hood insulation.
  • Tighten Clamps: Go back and tighten the clamp at the turbo coupler (don't over-torque or you'll tear the silicone) and the air filter base.
  • Power Up: Reconnect both negative battery terminals.
  • Start Engine: Start the truck. It is normal for the idle to fluctuate for a few seconds as the computer relearns the airflow. Listen for whistling sounds (air leaks).

Disclaimer: This guide is for reference only. Performance modifications may affect your vehicle's warranty. Always follow the specific instruction manual provided by the manufacturer of your intake kit.