This tutorial will guide you on how to install a K&N intake on a 2.5 Nissan Altima
K&N intake “kit”
8mm and 10mm sockets
ratchet and extension
philips and flathead screwdrivers
3mm and 5mm allen key wrenches
rags (box of rags works wonders)
1) Turn off the ignition and disconnect the negative battery cable.
2) Disconnect the mass air sensor electrical connection and then unhook the wiring harness clips from the air box. (use pliers if needed)
3) Using the 5mm allen key remove three bolts which secure the engine cover and then remove the engine cover. (Save the bolts)
4) Using a philips screwdriver (or an 8mm ratchet) remove the two bolts that secure the fresh air inlet assembly and remove the fresh air inlet assembly from the air box and radiator core support. (save the bolts)
5) Using pliers (if needed) release the crank case vent hose spring clamp and detach the crank case vent hose from the intake tube.
6) Using a philips screwdriver or a ratchet unscrew the the air box mounting bolt.
7) Using a flathead screwdriver loosen the hose clamp which secures the intake hose to the throttle body.
8) Remove the air box assembly.
9) Stuff some rags into the throttle body opening so that nothing will accidentally end up in the engine.
10) Remove the two rubber air box mounting grommets.
11) Install the 1.0” high rubber mounted stud onto the front air box mounting location using a 10mm ratchet in the following order nut, metal washer, rubber washer, mounting location, metal washer, 1″ rubber stud.
12) Install the 1/2” high rubber mounted stud onto the front air box mounting location using a 10mm ratchet in the following order nut, metal washer, rubber washer, mounting location, metal washer, 1/2″ rubber stud.
13) Using an 8mm ratchet Remove the lower-front throttle body mounting bolt. (save the bolt)
14) Install the tube mounting bracket (part number 070091 should be printed on the bracket itself) onto the throttle body using the bolt removed in the previous step.
15) Remove the rags from the throttle body opening and install the provided silicone hose onto the throttle body and secure with the smaller of the provided hose clamps using a flathead screwdriver.
16) Install the provided ¼”npt vent fitting into the K&N intake tube.
17) Using a philips screwdrive remove the two bolts which secure the mass sensor to the OEM intake tube and remove the mass air sensor.
18) Install the mass air sensor into the K&N intake tube and secure with the hex bolts using 3mm allen key.
19) Install the K&N Intake Tube into the silicone hose at the throttle body and align with the mounting bracket. Secure to the bottom of the bracket with a washer, locking washer, and nut using a 10mm ratchet from and a hose clamp using a flathead screwdriver.
20) Attach the edge trim to the heat shield starting by the pipe end and trim as desired/necessary (make sure the oblong hole is uncovered)
21) Install the heat shield mounting bracket onto the heat shield with a bolt washer and bracket on one side and a washer and nut on the other side of the heat shield using a 10mm ratchet.
22) Using a 10mm ratchet attach the heat shield to the rubber grommets with two nut-locking washer-washer assemblies.
23) Using a 10mm ratchet attach the L brace from the heat shield with another assembly.
24) Install the factory crank case vent hose to the ¼”npt vent installed onto the K&N intake tube.
25) Reconnect the mass air sensor electrical connection.
26) Open air filter slightly keeping most of the plastic cover on (so as not to get your hands covered in oil) and wipe excess oil off rubber tubing.
27) Install the air filter onto the K&N intake tube and secure with the provided hose clamp using a flathead screwdriver.
28) Remove remaining plastic from the air filter
29) Reinstall the fresh air inlet supply to the original location and into the fresh air tube on the heat shield then secure with the factory bolts.
30) Reinstall the engine cover and secure with the factory bolts.
31) Reconnect the negative battery cable.
32) Double check to make sure everything is tight and properly positioned before starting the vehicle.
32) Start up the engine and inspect installation for any air leaks or odd noises.
Originally posted by Marisha