Air intakes reduce engine intake temperatures by moving the intake opening away from the engine's heat. Reduced engine temperatures creates a denser air intake charge, which combines with more fuel to generate more power. Performance air intakes use a high flowing synthetic filter and an aluminum or polyethylene tube. These materials are constructed with smooth bends to reduce restriction and keep intake flow high.
How to Install an Air Intake
Materials Needed
From 2007 to 2011, the Jeep JK used the 3.8 liter engine. The JK now uses the 3.6 liter Pentastar engine. Although the steps are similar for intake installation, the locations of bolts and electrical connectors is different. These differences will be highlighted during the guide.
Step 1 – Disconnect negative battery cable
Use your 10mm socket and disconnect the negative (black) battery terminal. Refer to the article How to Replace the Battery on a Jeep Wrangler JK.
Step 2 – Remove your engine cover
The engine cover needs to be removed for access, pop it off and set it aside.
Refer to the article How to Replace the Camshaft Position Sensor on a Jeep Wrangler JK for detailed instructions. This step is not required for the 3.8 liter engine.
Step 3 – Remove the air intake tube
Start by removing the two bolts holding the intake tube to the air shroud. Remove the rubber line from the intake tube by pulling it out of the tube grommets.
Loosen the worm gear hose clamps at the air box and throttle body with a flat head screwdriver. Pull and twist the intake tube off the throttle body, but be careful as the air inlet temperature sensor connector is still attached. The sensor is located on the left side of the intake pipe near the throttle body. Disconnect the sensor by squeezing the flexible tab on the connector and simultaneously pulling the connector away from the sensor. Twist and pull the intake tube off the air box.
On the 3.8 liter, the I.A.T. sensor is located on the right side of the intake tube near the throttle body. The connector style is different. To disconnect it, slide the red locking tab up and squeeze the flexible tab while pulling the connector away from the intake tube.
Figure 1. The intake tube to air shroud bolts.
Figure 2. Removing the intake tube from the throttle body.
Figure 3. Removing the I.A.T. sensor on the 3.8 liter.
Step 4 – Remove the air filter housing
Disconnect the crankcase rubber vent hose from the plastic vent tube. Carefully pull and twist the rubber off the plastic, then lift up and remove the air box.
On the 3.8 liter engine, the crankcase hose connects to the air box. Once it's removed, loosen the clamp holding the intake tube to the throttle body, and pull upwards on the air box to dislodge it from the mounting grommets.
Figure 4. The crankcase hose location.
Figure 5. Removing the air box from the 3.8 liter engine.
Step 5 – Install the new air filter box
This step will vary by manufacturer, as each uses their own style of air box. Start by removing the bolt connecting the air box mount bracket to the inner fender. Also, remove the bolt that secures the radiator to the core support. Install the brackets, lid, and trim to the new heat shield. Leave off the top lid for now. Place the heat shield into the vehicle and tighten down the mounting bolts. This includes the two bolts removed from the air box mounting bracket and radiator core support. Install the new air filter into the air box and secure it with a hose clamp. Install the air box cover lid, making sure the lid mounting brackets are correctly positioned to create an air tight seal in the air box.
If you have a 3.8 liter engine, you'll need to remove both bolts from the air box mounting bracket and the power steering reservoir bolt. K&N also has you remove a bolt to the right of the power steering pump pulley to mount a bracket.
Figure 6. The air box mounting bracket bolt.
Figure 7. The power steering pump reservoir bolt.
Figure 8. Installing the new bracket on the 3.8 liter engine.
Step 6 – Install the new intake pipe
Install the new hose onto the air box and throttle body. Secure the hose to each with hose clamps. Before installing the new pipe, you'll need to screw the new vent fitting into the intake tube and remove/install the air temp sensor. The air temp sensor slides into a rubber grommet. Gently twist/pull it from the factory intake tube. Applying a small amount of Vaseline to the rubber grommet makes installation easier. Slide the new vent hose onto the vent fitting. The new intake may no longer have locations for the two air shroud mounting bolts. Zip tie the coolant overflow hose to a nearby component to achieve a factory style route if no new mounts are included. Now install the intake pipe into the air box and throttle body and tighten down the required hose clamps. Re-connect the crankcase vent hose to the vent tube and the I.A.T. sensor to the electrical connector. Finish the installation by re-installing the engine cover and re-connecting the negative battery cable.
Remember to re-install the power steering reservoir pump bolt for 3.8 liter engine owners.
To test for leaks, first start the engine. Listen for any hissing noises around the intake piping. If you have propane available, spray some around the intake tube connections. Rising engine RPMs while emitting propane indicates an air leak.
How to Install an Air Intake
Materials Needed
- Flat head screwdriver
- Ratchet
- Extension
- 15mm socket
- 10mm socket
- 4mm Allen wrench
From 2007 to 2011, the Jeep JK used the 3.8 liter engine. The JK now uses the 3.6 liter Pentastar engine. Although the steps are similar for intake installation, the locations of bolts and electrical connectors is different. These differences will be highlighted during the guide.
Step 1 – Disconnect negative battery cable
Use your 10mm socket and disconnect the negative (black) battery terminal. Refer to the article How to Replace the Battery on a Jeep Wrangler JK.
Step 2 – Remove your engine cover
The engine cover needs to be removed for access, pop it off and set it aside.
Refer to the article How to Replace the Camshaft Position Sensor on a Jeep Wrangler JK for detailed instructions. This step is not required for the 3.8 liter engine.
Step 3 – Remove the air intake tube
Start by removing the two bolts holding the intake tube to the air shroud. Remove the rubber line from the intake tube by pulling it out of the tube grommets.
Loosen the worm gear hose clamps at the air box and throttle body with a flat head screwdriver. Pull and twist the intake tube off the throttle body, but be careful as the air inlet temperature sensor connector is still attached. The sensor is located on the left side of the intake pipe near the throttle body. Disconnect the sensor by squeezing the flexible tab on the connector and simultaneously pulling the connector away from the sensor. Twist and pull the intake tube off the air box.
On the 3.8 liter, the I.A.T. sensor is located on the right side of the intake tube near the throttle body. The connector style is different. To disconnect it, slide the red locking tab up and squeeze the flexible tab while pulling the connector away from the intake tube.
Figure 1. The intake tube to air shroud bolts.
Figure 2. Removing the intake tube from the throttle body.
Figure 3. Removing the I.A.T. sensor on the 3.8 liter.
Step 4 – Remove the air filter housing
Disconnect the crankcase rubber vent hose from the plastic vent tube. Carefully pull and twist the rubber off the plastic, then lift up and remove the air box.
On the 3.8 liter engine, the crankcase hose connects to the air box. Once it's removed, loosen the clamp holding the intake tube to the throttle body, and pull upwards on the air box to dislodge it from the mounting grommets.
Figure 4. The crankcase hose location.
Figure 5. Removing the air box from the 3.8 liter engine.
Step 5 – Install the new air filter box
This step will vary by manufacturer, as each uses their own style of air box. Start by removing the bolt connecting the air box mount bracket to the inner fender. Also, remove the bolt that secures the radiator to the core support. Install the brackets, lid, and trim to the new heat shield. Leave off the top lid for now. Place the heat shield into the vehicle and tighten down the mounting bolts. This includes the two bolts removed from the air box mounting bracket and radiator core support. Install the new air filter into the air box and secure it with a hose clamp. Install the air box cover lid, making sure the lid mounting brackets are correctly positioned to create an air tight seal in the air box.
If you have a 3.8 liter engine, you'll need to remove both bolts from the air box mounting bracket and the power steering reservoir bolt. K&N also has you remove a bolt to the right of the power steering pump pulley to mount a bracket.
Figure 6. The air box mounting bracket bolt.
Figure 7. The power steering pump reservoir bolt.
Figure 8. Installing the new bracket on the 3.8 liter engine.
Step 6 – Install the new intake pipe
Install the new hose onto the air box and throttle body. Secure the hose to each with hose clamps. Before installing the new pipe, you'll need to screw the new vent fitting into the intake tube and remove/install the air temp sensor. The air temp sensor slides into a rubber grommet. Gently twist/pull it from the factory intake tube. Applying a small amount of Vaseline to the rubber grommet makes installation easier. Slide the new vent hose onto the vent fitting. The new intake may no longer have locations for the two air shroud mounting bolts. Zip tie the coolant overflow hose to a nearby component to achieve a factory style route if no new mounts are included. Now install the intake pipe into the air box and throttle body and tighten down the required hose clamps. Re-connect the crankcase vent hose to the vent tube and the I.A.T. sensor to the electrical connector. Finish the installation by re-installing the engine cover and re-connecting the negative battery cable.
Remember to re-install the power steering reservoir pump bolt for 3.8 liter engine owners.
To test for leaks, first start the engine. Listen for any hissing noises around the intake piping. If you have propane available, spray some around the intake tube connections. Rising engine RPMs while emitting propane indicates an air leak.
