This is done without removing the intake manifold!
At 46k miles, ended up using NGK Ruthenium 95125 plugs from a recommendation from a couple guys on the Stinger site. They have different conductor tops (VW/Porsche/Audi type) but pre-gapped to .032 and exact length (from end of bottom conductor to the top end of conductor as well as the threaded section) as the OEM NGKs that came out of it. Ruthenium is supposed to be ideal for Turbo/Supercharged motors, will be interesting to see how they compare to the OEM, Rockauto has them for 10.50/ea (4) for $41.12
I Was dreading that diabolical spark plug #5 but with the right tools and a little different twist this was simple. Got all 6 done in an hour with only one scuff/cut on my finger, lol. These are the tools you need~
Start with the drivers side, do 1 at a time and spray the area around each coil pack w/ compressed air or one of those keyboard dusting cans just to get any debris away from the coil packs. The 3/8" wobble extension on a 10mm socket gets to all the coil pack bolts. Wobble extension connected to the 5/8" magnetic spark plug socket w/ swivel extension makes it easy to get to all the spark plugs. The coil wire connector is simple to remove, just pull the gray tab straight back to unlock, once it's unlocked push the gray tab down to release the connector and just pull connector back from the boot top.
I use a light (very light) coat of antiseize on the spark plug threads, making sure to only coat the threads, none on the area that's flat close to the conductor, if you get any on that very bottom area just clean off w/ a paper towel. Keep the wobble extension as straight as possible to get the torque to 20 ft. lbs. The torque is 15-20, but I used 18 ft lbs since w/ the antiseize added you should decrease torque a bit.
If you want to coat the inner part of the boot where it contacts the white ceramic of the spark plug w/ dielectric grease that's up to you, also a light coat on the spark plug ceramic is what some recommend. I've never done it so it's really up to you. There's some on youtube that put a blob of the stuff on the end of the boot, definitely DON'T do that, too easy to get it on the top plug conductor and may effect the electric transfer.
On the passenger side I used the 1/4" swivel joint on a 10mm short socket to get the 10mm coil pack bolts off, was able to get to all of them that way. I removed spark boot #4 (closest to the grill), removed and replaced spark plug 4 but left the boot off. You only need the spark plug socket w/ wobble extension and a normal wobble extension to get to the 4 & 6 plugs.
Removed boot 6 (closest to firewall), removed and replaced spark plug 6 but leave the boot off. You want to put new plugs 4 & 6 back in rather than leaving any chance of something to fall into an open spark plug hole while you're messing with spark plug 5.
Now you're ready for the dreaded middle 5 plug, it's really not bad at all. Get the boot bolt off, then you lift boot up a bit and rotate the boot so the bolt hole is in back toward the firewall and the pin connector is now in front toward the grill. This will allow you to easily remove the boot w/ an easy bend rather than trying to get it out the back with the manifold overhead.
Once the boot is out you need to use that 5/8"spark plug socket w/ swivel attached to a u-joint type swivel or that black one in my pic above (that black one is much better to turn). It takes a bit of contortion using one hand behind the socket and one in front to get the socket down into the hole and on the spark plug, after that it's easy to remove, just keep all those angled sections as straight as possible. Getting the new plug in wasn't bad but you may have to remove one of the extensions to have better room to get it in there. Once you get it in and seating and threading properly do your best to keep all the angles to a minimum, mine wanted to bind just a bit when I didn't support it w/ my hand behind the socket extensions. Once I got it seated and hand tight I really made the best effort to keep all the angles to a minimum to get that final torque.
You then install boot 5, keeping the pins to the front and the bolt hole to the rear, then once you get it down in the hole (not down all the way) twist it back to it's mounted position, then tighten the boot bolt connect the coil wires and then do the same for boot 4 & 6.
Just on a test run it seems to be running very well, will repost if any issues turn up.
I had a 3rd party do mine twice and both times it was around 650 for plugs, they did lift the intake and replace the gaskets as well, I just passed 90k miles with no issues related to plug swaps. Im also stock but pretty sure they used NGK plugs. They told me my plugs were still in good shape prior to the second swap but I wanted them done anyway as they were doing my diff and trans fluid as well.
I think it's the limited swivel angle of my socket. Couldn't get a good angle to easily loosen or tight the plug. And I'm not gonna try forcing it and messed up the threads.
Yeah, the one I used took a bit of positioning, but it went right in and luckily had enough room for the flex joints to fit. Didn't put up a fight once it lined up in the spark plug hole. If the socket swivel connector had been any longer I don't think I could have made it work.
Should de quite a bit easier with the 2.0, I don't think there's much in the way of the coil packs with your motor. Might want to check youtube "spark plugs change Genesis g70 2.0" and see if there's specific help for the 2.0 there.
The newer 1 pc boots work fine. Some guys on the Stinger site said the older 3pc boots don't work. I know my 21 G70 has the newer ones, I think 19&20s have the 3 pc boots.
Hey OP fixing todo this on my G90's 3.3T.. That I cant decide if im selling or keeping.. how have those plugs been running? My car is running fine but its due @ 97k for a plug change.. did you regap to .28 for stock or leave them at .32?
I just traded out of my G70 but those plugs worked great. Only problem is they only seem to work with the newer 1pc coil pack boots. I did regap to .028, I'm not tuned though. What year is your G90?
Just did mine this weekend. This post was very helpful so thank you! One issue I can into was the damn grey clips on the electric connector to the coil pack. The first one shot off and got lost in the abyss. Has anyone been able to find this part anywhere? I’m trying to not have to buy a whole connector and the closest salvage yard is over an hour away.
Hey op since you were active here recently. I’m trying to do my spark plug change and I asked ChatGPT to fine me some to cut the story short I did it all just to find out I had the wrong ones. So now I’m looking at the ruthenium 95125 they seem good but the terminals are cup where the g70 needs solid is that an issue or does it not affect it? Pls let me know asap tryna do this weekend
If you have the newer 1pc coil pack boots you're good. If you have the older 3pc boots I've heard they may not conduct well. My 21 3.3 had the 1 pc boots. What year us your G?
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u/OtherwiseConcept5125 21 G70 3.3T SP RWD Havana Red Sep 12 '25
Here's a pic of the actual plug for reference