How to change spark plugs on 2007+ G35/G37

The G-Series Tuning Forum is the place to discuss G35/G37 performance modifications and mechanical repair.
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gwoods
Posts: 3896
Joined: Fri Jul 27, 2007 11:57 am
Car: 2013 Infiniti M37x
1999 Nissan Altima SE limited 5spd
1992 Miata (soon to be turbo)
1965 Cj-5 with 327 v8
2012 Toyota Sequoia Limited
Location: Phoenix

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Changing Spark Plugs on 07+ G35 and G37

Tools: 10mm, 11mm 12mm and 14mm sockets5mm Allen keytwo 3/8 drive 12” extensions3/8 drive U jointMagnate on stickDi-Electric GreaseAnti-Seize 3/8 in diameter rubber hose 12” long

Using 10mm socket remove plastic intake manifold coverUsing 11mm & 10mm socket remove intake plumbingUsing 5 mm Allen keys remove both throttle bodies

Only work with 1 plug at a time so there is no danger of mixing anyparts.

Using a 10mm socket and your fingers unclip the wires to the coil pack and then remove the 10mm bolt that holds the coil pack in place. Lift the coil pack out and lube with di-electric grease.

Using a 14 mm socket very gently loosen the spark plug. The heads are aluminum so pay attention to what you are doing. The wrench and socket need to be straight into the hole so you don’t damage any threads.

Using the magnate on a stick fish out the spark plug. You can check the gap on the old spark plugs I don’t recommend checking the gap on the new plugs.Take a new spark plug, using a cloth coat the threads with a light coat of anti-seize lube. This will make it possible to change the plugs again. Push the back of the new spark plug into a clean section of rubber line. Then feed it into the hole, use the rubber line to start the plug. This lessens the chance of cross threading the spark plug. Once you have about 4 good turns on the plug pull the rubber line off the back and use a 14mm socket to put it in finger tight. The torque specs are 168 inch pounds or 14 foot pounds use a torque wrench so you don’t over tighten and damage threads.

Replace the coil pack and secure it with the 10mm bolt.

Move to the next plug.

The entire process should take about 2 hours.

I had 3 plugs that were very far out of range with the upper electrode worn away. My car has 69,000 very hard miles on it. The decision to change plugs is a result of gas mileage dropping to 19 mpg from 21 mpg. Rough idle and part throttle hesitation.


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SVTCOBRA
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Good Job!!! Will have to do this eventually since I traded the 05 for the 08


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G_whizz
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Car: 2010 G37 Coupe Sport
Location: Canada eh

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Nice job Jeff!!



Thanks for taking the time to do this! I'll get this added ASAP!


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gwoods
Posts: 3896
Joined: Fri Jul 27, 2007 11:57 am
Car: 2013 Infiniti M37x
1999 Nissan Altima SE limited 5spd
1992 Miata (soon to be turbo)
1965 Cj-5 with 327 v8
2012 Toyota Sequoia Limited
Location: Phoenix

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I have Diff fluid, serpentine belt and power steering fluid too. I sent the Serpentine Belt change to Greg about a month ago.

I'm planning on bleeding brakes one Sunday this month so I'll have that too. Then probably in another 80k miles Automatic Transmission rebuild! I am sure even changing the fluid every 20-30k miles the clutches are wearing out.

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G_whizz
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Car: 2010 G37 Coupe Sport
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Kewl..post them here or email me. Greg has 764872648726487264 things going on..so he can be hit and miss.

Really appreciate the hard work!


dohio69
Posts: 18
Joined: Sun Oct 11, 2009 9:23 pm

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Hi really colorful explanation aldowhat are the model # for a top brand as denso or ngk in a vq35HR???and how long between changes with hard use as you say???thnx for ur help

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gwoods
Posts: 3896
Joined: Fri Jul 27, 2007 11:57 am
Car: 2013 Infiniti M37x
1999 Nissan Altima SE limited 5spd
1992 Miata (soon to be turbo)
1965 Cj-5 with 327 v8
2012 Toyota Sequoia Limited
Location: Phoenix

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The factory plugs are Denso Infiniti part number 22401-EW61C

I changed mine at 69k and 3 of the 6 were very worn down. I will change plugs again around 140k and again at 200k.

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telcoman
Posts: 5763
Joined: Sat Jul 08, 2006 11:30 am
Car: Tesla 2022 Model Y, 2016 Q70 Bye 2012 G37S 6 MT w Nav 94444 mi bye 2006 Infiniti G35 Sedan 6 MT @171796 mi.
Location: Central NJ

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gwoods wrote:The factory plugs are Denso Infiniti part number 22401-EW61C

I changed mine at 69k and 3 of the 6 were very worn down. I will change plugs again around 140k and again at 200k.
Nice write up.

Here is what mine looked like at 106.7k miles



I had the dealer do it as it is too cold now in NJ

The gaps ranged from .40 to .55"

They are NGK PLF R5A

Telcoman

User avatar
gwoods
Posts: 3896
Joined: Fri Jul 27, 2007 11:57 am
Car: 2013 Infiniti M37x
1999 Nissan Altima SE limited 5spd
1992 Miata (soon to be turbo)
1965 Cj-5 with 327 v8
2012 Toyota Sequoia Limited
Location: Phoenix

Post

WOW thanks for posting that and your probably one of the more conservative G owners on the forum too.

55 thousands is pretty far out! and none of yours were in range.

Besides being worn out the plugs look great none of them are burned from running lean a testament to your claim that 87 octane works just fine.

One of the techs offered to make a change to my ECU where he would take out 4 degrees of timing from the car perminately but I would always need to run 91 octane which I always do. I didn't take him up on the offer.

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telcoman
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Car: Tesla 2022 Model Y, 2016 Q70 Bye 2012 G37S 6 MT w Nav 94444 mi bye 2006 Infiniti G35 Sedan 6 MT @171796 mi.
Location: Central NJ

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gwoods wrote:WOW thanks for posting that and your probably one of the more conservative G owners on the forum too.

55 thousands is pretty far out! and none of yours were in range.

Besides being worn out the plugs look great none of them are burned from running lean a testament to your claim that 87 octane works just fine.

One of the techs offered to make a change to my ECU where he would take out 4 degrees of timing from the car perminately but I would always need to run 91 octane which I always do. I didn't take him up on the offer.
They cleaned the throttle body as well. The vehicle felt "WOW" when I got it back. I had a 2009 loaner with 765 miles on it. My G felt as powerful as the 09 when I left the dealer with the new plugs. I guess I got my moneys worth out of them. New belts and antifreeze flush. What a treat for my G I guess it deserved it after 4 years.

My MPG so far has not improved with the new plugs but I attribute that to the cold weather.My G has never liked cold weather. I did my 5th 1230 mi round trip to Florida on the old plugs. It was warmer on the way down than itwas on the way back. I got 24MPG on the old plugs on the way down and 23MPG on the way back. I'm still getting 23 even with the new plugs but hopefully that will increase once the weather warms?

Telcoman

User avatar
gwoods
Posts: 3896
Joined: Fri Jul 27, 2007 11:57 am
Car: 2013 Infiniti M37x
1999 Nissan Altima SE limited 5spd
1992 Miata (soon to be turbo)
1965 Cj-5 with 327 v8
2012 Toyota Sequoia Limited
Location: Phoenix

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how did you feel about the 7 speed auto? I was annoyed by all the shifting and my 07 G is faster.

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telcoman
Posts: 5763
Joined: Sat Jul 08, 2006 11:30 am
Car: Tesla 2022 Model Y, 2016 Q70 Bye 2012 G37S 6 MT w Nav 94444 mi bye 2006 Infiniti G35 Sedan 6 MT @171796 mi.
Location: Central NJ

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gwoods wrote:how did you feel about the 7 speed auto? I was annoyed by all the shifting and my 07 G is faster.
Mileage update

The weather warmed up the past few days and after this afternoons fillup my MPG was back up slightly over 24.

As for the 7 speed, te car was quick, and powerful. I put slightly over 150 miles on it.At 80 the RPMS are considerably lower and it seems to use less gas than the 5 speed autos.

It had XM radio but I prefer my Sirius. No one it seems can explain to me why CNBC channel 129 on Sirius scrolls most active stock quotes and CNBC channel 127 on XM does not?

The dealer also mentioned the bushings in the lower control arms are wearing but they are still ok.

I have now made five round trips from NJ to Florida with my G over the past four years. The 2009 loaner was as comfortable as my 2006 and I wouldn't have a problem spending 12 hours and 600 miles behind the wheel in it.

Telcoman

orthogod1
Posts: 2
Joined: Fri Apr 20, 2012 7:52 pm
Car: 2008 G35

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Hugh Shoutout. Your post made this an easy task. Changed plugs in 1 hour 20 min. Easiest job I have ever done and those mutts at infiniti wanted 295.00 labor. THANKS AGAIN!!!!

v36nspec
Posts: 5
Joined: Sun Nov 04, 2012 12:54 pm
Car: 2007 G35x sdn

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Anyone who has done their own sparkplugs on their g35 HR notice any oil in the spark plug tubes? I know the VQ35DE V35 G's as well as early Z's had this problem, me being one of them with my 03 350z. Wanted to know if the upgraded VQ35HR's have this potentially continuing problem... I know this may be asking much, as most of 07's and 08' G owners haven't put enough miles on the clock to warrant a sparkplug change. We're close!

tgeml
Posts: 5
Joined: Wed Mar 04, 2015 7:15 pm
Car: 2008 G35X Premium Package + Tech Package.

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Yes, my 2008 G35X went into the dealership under my extended warranty for this exactly. I was changing my plugs during my 87500 maintenance and the passengers side rear plug well had oil pooling in it and all over the plug. The dealership said that they also found pooling oil in plugs 3 and 4 on the drivers side. Both of my valve covers, valve cover gaskets, and upper plenum gaskets were changed out. Thank god I had a 100 dollar deductable 3rd party warranty which covered the work, or else id be out 1100 dollars. Ill post pictures of my old plugs soon.

It was difficult handing my courtesy loaner vehicle in, the dealership let me drive a 2015 QX60 for the 5 days the car was in the shop, damn was that thing nice, even the CVT was acceptably good.


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