In this tutorial, you will learn how to replace the spark plugs on Nissan V6 3.5L engine. Nissan recommends that you replace the spark plugs every 105,000 miles. This recommendation can vary if you have iridium, platinum or standard spark plugs. Replacing the spark plugs yourself will typically cost most DIYers from $25-$60 for parts and two to three hours of work.
Park you Nissan on a level ground. Allow your Nissan or Infiniti engine to cool down.
Step 2: Open Hood
Pull the hood release on your Nissan and open the hood.
Step 3: Disconnect battery
Disconnect the negative battery terminal on your Quest
Step 4: Remove Engine Cover
Remove the engine cover.
Step 5: Remove Ignition Coils
Unplug the electrical connector from the ignition coil. Press the small tab then pull. Do this for all three front coils.
Remove the 10mm bolts that secure the coil in place. Pull the coils out.
This engine also has three coils hidden under the intake manifold. To replace those spark plugs, remove the intake manifold by removing the 10mm bolts that hold it in place. Disconnect the air intake from the manifold. Remove any hoses and pull out the intake manifold.
Step 6: Remove Spark Plugs
Use the spark plug socket, extension, and ratchet to remove the spark plugs from your Nissan. Use a magnetic pickup tool to pull out the spark plugs.
Step 8: Install new spark plugs
Use anti-seize on the spark plug threads. Install new spark plugs by hand on your Nissan until they are finger tight. Then use a ratchet to tighten an additional 1/4-1/2 turn. Ideally, use a torque wrench to tighten the spark plugs. Typical torque values are 10 to 15 lb-ft for 14mm threads and 15 to 20 lb-ft for 18mm plugs.
Standard spark plugs should be gapped to 0.043.
Step 9: Install Igntion Coils
Ensure the connectors don't get mixed as they need to be in the same coil as before removal.
Step10: Start the car
Reinstall the engine cover. Reconnect the negative battery terminal. Remove any tools from the engine bay and start the car.