hello guys...

got a noob question here...I have done some search but i cant seem to find the answer...

at what mileage or timeline do I need to replace the spark plugs for my 2004 G35 5AT??

I have looked through the service manual as well as Infiniti help website but neither one indicates the time/mileage when the spark plugs need to be replaced....

is it something that's totall up to owner's choice?!

and also.. what benefit would it give to me to replace the spark plugs?? bettter gas mileage, gaining loss hps?????

and last question.. What's a reasonable price to have someone other than the dealership done the job for me (labor + parts)......

thanks in advance for your inputs...
Modified by Smartidiot at 7:33 PM 12/12/2007

I'm going to a dealership for an flashing airbag light issue. I'm curious about that too - I'll check with them regarding the spark plugs and let you konw.

OEM Plugs are good till about 100k...

joe603 wrote:OEM Plugs are good till about 100k...

Hi Joe,

So are we talking about 100,000 miles here or 100,000kms??

just to make sure since i am from Canada......

thanks again!

LOL! miles...so 160k kms.

I have another stupid question... Where are the spark plugs?? Do I have to take the stupid engine cover off to get to them?

yup. they're a pain in the butt to change too.

100k?! Wow!I'm so used to my old '96 camry which required new ones every 35-40k or so. I love it! Thanks for the info!

stephenbaird wrote:100k?! Wow!I'm so used to my old '96 camry which required new ones every 35-40k or so. I love it! Thanks for the info!

You didn't mention which engine you had but I'm assuming it was a V6?I had a 92 Lexus 5 speed for 14 years which had the same engine. I sold it over book value with over 100k miles and never changed the spark plugs. Most spark plugs in new Japanese cars sold in the last 10 years or so are good for 100k miles. What I generally do around 50k miles is remove and inspect them and place a little high temp grease on the threads so they do not sieze in the head. I'll probably attempt this on my G in the spring 2008. I have 45k miles now. I'll let you know how difficult it is. On my Lexus there was one plug that I could not access to remove.Perhaps one of the Infiniti techs can let us know if any special ratchets, entension bars or other part removals are necessary, to remove all 6 plugs?

Telcoman

stephenbaird wrote:100k?! Wow!I'm so used to my old '96 camry which required new ones every 35-40k or so. I love it! Thanks for the info!

Nissan parts rep here. The 350z and the g35 (vq35de or vq35hr) part # is 22401-5m015 for the spark plugs and they do not recommend replacement till 105, 000 miles.

Here you go!

TOOLS:

6 OEM plugs (part # is 22401-5m015) or equivalent 3/8" Rachet3/8" long extension (at least ten inches)10mm socket16mm "deep" socket (or "sparkplug socket")Magnetic pick up tool3-prong grabber (optional, you'll need it if you don't have a "sparkplug socket")PliersTorque Wrench

Most people would have these tools in their garage. The long extension is a must. The magnetic and pronged "pickup tools" make this much easier.

PROCEDURE:

1) DISCONNECT THE NEGATIVE BATTERY TERMINAL!2) Remove the engine cover. it is 2 10mm nuts and 2 10mm bolts3) Remove the intake tube. This should require the removal of (1) 10mm bolt and 2 hose clamps. Don't forget to disconnect the rubber breather tube; use pliers to loosen the clamp. Tne pull the rubber tube away from the intake pipe.4) Let's start on the driver's side first.5) There are 3 coils on each head. They are held in place with a single 10mm bolt. Underneath these coils are the sparkplugs.6) to gain better access to the coils, you'll need to remove 3 10mm bolts which hold down an electrical harness just above the coils. All the bolts are easy to get to. You may have to push a couple hoses out of the way to get the back bolt though. Be careful not to drop the bolts!!! The magnetic pick-up tool can be very helpful here!7) After you have removed the bolts for the electrical harness, Disconnect the plugs going to the individual coils. There are 3 plugs to undo. They are snug, but they come off fairly easily with just your fingers. Remember which plug goes to which coil. That is extremely important!!!!8) Now you have good access to the coils! Use the 10mm socket to remove the bolt from the coil. Once you have removed the bolt, the coil will pull straight up out of the head. This should be very easy to pullout.9) You should be able to see the spark plug in the hole. It is pretty far down there.10) Use the 16mm socket with the extension to remove the plug. If you aren't using a sparkplug socket, you'll need to use a 3-prong, spring loaded pick-up tool. This tool makes plucking the plug out the head very easy. I'm sure you can come up with some other sort of tool to do the job, but that is what I used.11) Replace the spark plug with your new plug! Torque the plug to 20 FT-LBs! Make sure not to crossthread or overtorque the plugs! Aluminum heads are easy to strip out!12) Replace the coil; torque its bolt to 95 IN-LBs and plug it back in to the harness.13) Repeat steps 8-11 for the other 2 cylinders!14) Now, you have completed the driver's side of the engine. Don't forget to bolt the wiring harness back into position with its 3 10mm bolts. 15) You can also replace the intake tube at this time.16) On to the passenger's side of the engine.17) This side is slightly harder....only because some of the bolts are difficult to reach by hand.18) I started by removing 2 10mm bolts which retain the wiring harness. I only removed the 2 bolts closest to the front and middle of the head. The rear bolt is not necessary to remove.19) You will need to remove the rubber breather tune that runs from the valve cover to the intake manifold. Use the pliers to loosen the clamps; then, slide the tube off of the engine.20) Now, you should be able to disconnect the electrical plugs from the coils. This is the same as on the driver's side.21) The coil removal and plugs change is the same as described above. The only difference is that the back (toward firewall) coil bolt is difficult to get to with your fingers. Use the magnetic tool to remove and replace this bolt.22) After repeating the procedure for all the cylinders, you should be done. Make sure to check that all the electrical connectors are snug and "clicked" tight.23) Very important, you shouldn't have any extra bolts laying around!!!!24) put the engine cover back on. Secure it with its 4 fasteners25) reconnect the negative battery terminal.26) YOU ARE DONE!!!!!

Ummm... nice one Mr Joe... let's get this added to the How to tech pages as well!!

this is what i like about this site.. always plenty of help.....but i found this piece of information that it seems like one of the Toronto dealership recommends spark plug replacement at 10800km rather than 10800miles..

(competing forum) (competing forum)

Is it true or they are just shxting us to get more money!?!?!?

Call around to other dealers...

Trust us, it's 100k miles.

G_whizz wrote:Ummm... nice one Mr Joe... let's get this added to the How to tech pages as well!!

Working with Noah on it....

joe603 wrote:Here you go!

TOOLS:

6 OEM plugs (part # is 22401-5m015) or equivalent 3/8" Rachet3/8" long extension (at least ten inches)10mm socket16mm "deep" socket (or "sparkplug socket")Magnetic pick up tool3-prong grabber (optional, you'll need it if you don't have a "sparkplug socket")PliersTorque Wrench

Most people would have these tools in their garage. The long extension is a must. The magnetic and pronged "pickup tools" make this much easier.

PROCEDURE:

1) DISCONNECT THE NEGATIVE BATTERY TERMINAL!2) Remove the engine cover. it is 2 10mm nuts and 2 10mm bolts3) Remove the intake tube. This should require the removal of (1) 10mm bolt and 2 hose clamps. Don't forget to disconnect the rubber breather tube; use pliers to loosen the clamp. Tne pull the rubber tube away from the intake pipe.4) Let's start on the driver's side first.5) There are 3 coils on each head. They are held in place with a single 10mm bolt. Underneath these coils are the sparkplugs.6) to gain better access to the coils, you'll need to remove 3 10mm bolts which hold down an electrical harness just above the coils. All the bolts are easy to get to. You may have to push a couple hoses out of the way to get the back bolt though. Be careful not to drop the bolts!!! The magnetic pick-up tool can be very helpful here!7) After you have removed the bolts for the electrical harness, Disconnect the plugs going to the individual coils. There are 3 plugs to undo. They are snug, but they come off fairly easily with just your fingers. Remember which plug goes to which coil. That is extremely important!!!!8) Now you have good access to the coils! Use the 10mm socket to remove the bolt from the coil. Once you have removed the bolt, the coil will pull straight up out of the head. This should be very easy to pullout.9) You should be able to see the spark plug in the hole. It is pretty far down there.10) Use the 16mm socket with the extension to remove the plug. If you aren't using a sparkplug socket, you'll need to use a 3-prong, spring loaded pick-up tool. This tool makes plucking the plug out the head very easy. I'm sure you can come up with some other sort of tool to do the job, but that is what I used.11) Replace the spark plug with your new plug! Torque the plug to 20 FT-LBs! Make sure not to crossthread or overtorque the plugs! Aluminum heads are easy to strip out!12) Replace the coil; torque its bolt to 95 IN-LBs and plug it back in to the harness.13) Repeat steps 8-11 for the other 2 cylinders!14) Now, you have completed the driver's side of the engine. Don't forget to bolt the wiring harness back into position with its 3 10mm bolts. 15) You can also replace the intake tube at this time.16) On to the passenger's side of the engine.17) This side is slightly harder....only because some of the bolts are difficult to reach by hand.18) I started by removing 2 10mm bolts which retain the wiring harness. I only removed the 2 bolts closest to the front and middle of the head. The rear bolt is not necessary to remove.19) You will need to remove the rubber breather tune that runs from the valve cover to the intake manifold. Use the pliers to loosen the clamps; then, slide the tube off of the engine.20) Now, you should be able to disconnect the electrical plugs from the coils. This is the same as on the driver's side.21) The coil removal and plugs change is the same as described above. The only difference is that the back (toward firewall) coil bolt is difficult to get to with your fingers. Use the magnetic tool to remove and replace this bolt.22) After repeating the procedure for all the cylinders, you should be done. Make sure to check that all the electrical connectors are snug and "clicked" tight.23) Very important, you shouldn't have any extra bolts laying around!!!!24) put the engine cover back on. Secure it with its 4 fasteners25) reconnect the negative battery terminal.26) YOU ARE DONE!!!!!

Thanks Joe

Great post

Telcoman

Pull one gap it and visably inspect it for wear.

I change my plugs every 40,000 miles or so. Will the car run fine with plugs that have 100,000 miles on them? Yes yes it will.

Can you loose some power & fuel economy from plugs with 100,000 miles on them? Yes yes you can.

i've heard/read that the plugs should be torqued to 15 foot-pounds (180 inch-pounds)...whats the real number because im doing going to be changing my plugs tomorrow and i wanna make sure im doing it right. also it is necessary to torque down the screws that hold the coil pack on or can you just hand tighten it and then a little more with the ratchet?

Did you check the FSM in the FAQ section??

I didn't torque mine...

joe603 wrote:yup. they're a pain in the butt to change too.

TROOF!

update

I decided to let the dealer replace the plugs at 106.7k miles. Also had the belts changed and the cooling system flushed.



Now at 112.5k miles and runs like new. Get 25MPG + in warmer weather. Regular 87 octane of course

Telcoman

The FSM states 105,000 miles spark plug interval.

HOWEVER - if you care about your car I would not wait until then.

I would change at 60K miles. I change mine every 40-50K with the Stock Platinum or even the Iridium tip. If you go with the cheaper copper version (good spark) you will want to change every 30K miles.

IMO.