Figured I'd put this out there for anyone who was interested in changing their spark plugs on their own but wasn't feeling very comfortable. I have a 2007 M35x so, at the least, this would be the same for the 2006 M35. I haven't seen the V8 or the 08/09 car so I can't say if this process is any different. This should give you the general idea though.

*Disclaimer* - I am not liable for anything you do to your car. This is just a basic walkthrough.

I took the pics with my HTC EVO 4G from Sprint (love this phone). End of shameless plug lol.

Task: Change The Spark Plugs
Time: Took me 2 hrs because I was super careful and had to figure this motor configuration out (I'm coming from a VQ30DE - 99 Maxima)
Tools/Supplies Needed:

• Socket wrench
• 14mm deep socket for the spark plugs (I'm not exactly sure of this size because I forgot to make note of it - I'm pretty sure it's 14mm)
• 10mm socket + varying length extensions for all the bolts/nuts you have to take off
• 6 spark plugs of your choice (I used 6 NGK V-Power copper plugs). Nissan motors work best on NGK plugs.
• Spark plug gapping tool. Napa sells them for like a dollar. The plugs should be pre-gapped to .044" but I like to double check.
• Flat head screw driver
• An extendable magnet (this helps greatly in getting some of the bolts out without dropping them below the motor)

Process:

1) Open the hood and remove the plastic covers to give yourself some space. The engine cover is held on by 4 10mm bolts/nuts. The other two just pop off with clips.



2) Disconnect part of the air intake that goes into the throttle body and move it to the side (I wire tied it to a hole near the fender).



Should look like this when you're done with the first two steps:



3) Loosen the engine harness by taking off the following two 10mm bolts. This will give it some slack so you can pull the coil packs out.



4) Disconnect the PCV Hose to again offer a little more space to get the coil packs out.



5) Unscrew this bracket (not sure what sensor this is) to allow you to remove the middle coil pack on the passenger side of the car.



6) Remove the two 10mm bolts holding this sensor/bracket on the driver side part of the engine:



7) Now what you're left with is 6 coil packs and spark plugs. Each coil pack has 1 10mm bolt holding it to the block. I only have a picture of two of them, but you should be able to figure this part out. Be careful unclipping the harnesses.



8) Once you remove the coil packs, you should be left with just the plug.



9) I believe the spark plug is 14mm deep socket, but I forgot to note this so I'm not exactly sure. Be careful unscrewing/screwing it in and the rest is reverse of removal.

eXcellent write up bud! i vote to make this a sticky!

I have a FAQ/HowTo thread (that you've probably seen) but I have no idea why the mods haven't noticed it and made it a sticky. It's in that thread (linked to here). This way there is only one sticky needed for all howto's with links to the respective stickys.

Good job. Just to add to this. make sure you label the coil pack wires so you know which one goes into which cylinder. I made an expensive mistake and reversed two cylinders. Cost me $2000 in repairs because the misfiring was just sending unburned gas into the cat which caused it to explode and melt away

M

This is a good post. What plugs did you go with?

msvara wrote:Good job. Just to add to this. make sure you label the coil pack wires so you know which one goes into which cylinder. I made an expensive mistake and reversed two cylinders. Cost me $2000 in repairs because the misfiring was just sending unburned gas into the cat which caused it to explode and melt away

M

wow really? i've experiencing a lot of misfiring on my german audi but the cat is still in one piece. that's interesting to know about the infiniti misfiring issue.

msvara wrote:Good job. Just to add to this. make sure you label the coil pack wires so you know which one goes into which cylinder. I made an expensive mistake and reversed two cylinders. Cost me $2000 in repairs because the misfiring was just sending unburned gas into the cat which caused it to explode and melt away

M

Very good point. I typically look at the plug because they usually are 'bent' a certain way (from the wires being one way for a long long time). I came across that issue with the pack nearest to the firewall on the driver side. I wasn't sure which plug went in, but after looking at the plugs and seeing how they were 'leaning' towards a certain pack, it worked out okay.

1M2NV wrote:This is a good post. What plugs did you go with?

I went with the V-Power ones that go for $4.99. I believe they are the copper ones. Last about 30k, I might try platinum next time.

I thought I could get away with that too, however for some reason two of my wires were supposed to be xcrossed. I forgot this part and when I re-connected it began deiseling like crazy, however that wasn't the worst part. I had no idea why this was happening so I began driving it like this hoping it was an adjustment thing and it would eventually go away. Around 10kms away I began smelling coolant and decided to stop and get towed the rest of the way to the dearlership.

If I ever decide to do this again I'm going to label each connector before I take them off.

Cheers,
M

Lesson learned I suppose. Sorry to hear about your troubles.

Don't forget a dab of anti-seize on the new plug threads.

EcstaSPT wrote:Don't forget a dab of anti-seize on the new plug threads.

That & the correct torque on the wrench when installing. Seems like common sense, but you'd be amazed at how many cars I've worked on where the plug was just hand tight (or so tight it bonded).

I do it hand tight + another couple of small turns to be safe. Never had issues and I've been doing my own work since I was 16 (I'm 23).

infiniti_lineup wrote:Again, IlyaKol, your posts aren't going unnoticed! Please continue showing your support for NICOclub and posting helpful tutorials, such as this one.

As usual, your original post has been converted into an article which can be found by clicking here.

Thanks for everything!

Glad I could help!

thanks for this awesome post! i will b changing the plugs this week!

No problem. Glad I could help.

Anybody have any tricks to get the spark plugs out? After I loosen them up I can get em out.

This is great. This will come handy when I do the plug replacement in July.

antzrus wrote:

Good Idea!! Blow up my car and use the insurance money on a down payment for an M56!!

nolmt50 wrote:Anybody have any tricks to get the spark plugs out? After I loosen them up I can get em out.

Use the spark plug wire to pull out the plug once it's completely loose.

wingFeather wrote:

EcstaSPT wrote:Don't forget a dab of anti-seize on the new plug threads.

That & the correct torque on the wrench when installing. Seems like common sense, but you'd be amazed at how many cars I've worked on where the plug was just hand tight (or so tight it bonded).

SO what is the torque supposed to be then? I will be doing my spark plugs in a week or two and dont want to screw it up. First time I will be doing the spark plugs myself. The dealership wants and outrageous amount of money to do them.

^you'll be good using anywhere 15-22 ft/lb...

When I changed mine out, it took me approx 1.5 hours

Just make sure you have all the tools prior to starting.. I gapped the spark plugs the night before.

I know there's some videos on YouTube as DIY for spark plug change on the VQ35's

Every 'mechanic' should have a magnet of some sort in their tool kit. When I loosen the plugs, I take a magnet inside there and it grabs the plug and I pull it out. Same thing for 'dropping' them in there.

CPJ LB wrote:^you'll be good using anywhere 15-22 ft/lb...

When I changed mine out, it took me approx 1.5 hours

Just make sure you have all the tools prior to starting.. I gapped the spark plugs the night before.

I know there's some videos on YouTube as DIY for spark plug change on the VQ35's

what did you gap them too? I am doing spark plugs soon and want to make sure things go smooth

For the Vq35DE, service manual states gap should be 1.1 mm or 0.043 inches

This is great thanks for the info changing my plugs in a couple of weeks along with various other maintenance items thanks again

Anyone got the process for a 2009 M35x?

Good stuff IlyaKol,
I ordered 6 coils & spark plugs from Rock Auto. They had best prices I could find for Hitachi coils, which are supposedly the OEM coils for this application. I have a code PO304, #4 cyl. misfire. I did not drive it too long after the light came on, but I am concerned about the CAT. As SVARD75 pointed out, raw fuel & cats do not get along!
I pulled 2 coils following your guidleines. (#2 coil & PO304 code suspect #4 coil). I put an ohm meter across multiple points of the coils, & did get a reading between the 2 of them that did not match. Maybe I will get lucky with a bad coil! I did not order coil boots, not sure if new coils come with them or not! I will probably change out the 3 plugs & coils on the problem side & re-check for codes before moving on to the other side of the engine. Total for parts & shipping came to $348.00.

The other way you could see is just moving the OEM coilpacks around and see if the misfire follows it before installing the new ones (therefor making them non-returnable in many cases). If the misfire follows the coilpack, then you know it's a bad coil and can proceed installing a new one. If it doesn't, then you have some other issue.

Ilya - thanks for creating this! I changed my plugs out today and followed your instructions - the car runs great. One plug was near failure, so I'm glad I did it.

I found the perfect tool for this job - GearWrench 80546 5/8-Inch x 6-Inch Swivel Spark Plug Socket- it has a built in magnet and makes changing the plugs so much easier. I bought it with the plugs from Amazon:
- http://www.amazon.com/gp/product/B0014Z ... ge_o08_s00