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100k spark plug change

Old Jun 1, 2025 | 11:20 PM
  #1  
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100k spark plug change

I changed my plugs which I’m pretty sure were original after 100k miles. There do seem to be some deposits which would indicate some less than ideal valve sealing. Still, doesn’t look terrible for 100k miles. My car was tending to hesitate in first gear and seemed to get bogged down occasionally after fully releasing the clutch, even with what I consider an appropriate amount of accelerator pedal input.

car seems to cold idle a bit better and it’s still very early but I think the occasional sluggishness in first gear is improved.

Looks like the coil pack bolts have never been removed. The two rusted heads were for cylinders two and three, probably because the py didn’t get the rust preventative oil bath from the previous owner that added oil like it was a champagne shower.
Looks like the coil pack bolts have never been removed. The two rusted heads were for cylinders three & four, probably because they didn’t get the rust preventative oil bath from the previous owner that added oil like it was a champagne shower.

Cylinder 2 coil pack had some noticeable red/terra Cotta looking marks. I wonder what this could be.
Cylinder 2 coil pack had some noticeable red/terra Cotta looking marks. I wonder what this could be. The coils look very clean, I’m doubting these are the original ones from the factory. I like the design with a rubber gasket that fits over the plug hole tube, creating a nice seal against moisture or crud getting inside.

Old plugs, cylinder 1 through 4, from left to right. Electrode gap still looks ok but there are some whiteish deposits on the insulator and the ground electrode, probably from leaky valve seals.
Old plugs, cylinder 1 through 4, from left to right. Electrode gap still looks ok but there are some whiteish deposits on the insulator and the ground electrode, probably from leaky valve seals.
I opted for Iridum IX, lower life but higher performance plugs which I will likely change after 50k kilometers or so.
I opted for Iridum IX, lower life but higher performance plugs which I will likely change after 50k kilometers or so.
Opted for the cardinal sin of antiseize. Internet experts will predict my car will blow up after 500 miles. I’d rather not have to deal with a seized plug. NGK says up to 14.5 lb*ft of torque
Opted for the cardinal sin of antiseize. Internet experts will predict my car will blow up after 500 miles. I’d rather not have to deal with a seized plug. When I removed the plugs, they were in their good. I’d say it took a good 30-35 lb*ft of torque to break em free. I know NGK says not to apply anti seize but NGK will not wipe my tears either if I chowder my aluminum threads due to a seize plug . Also applied some dielectric grease to the ceramic insulator and a bit on the coil boots. Was extra careful not to get dielectric grease on the threads, or anti seize on the ceramic body.

NGK says up to 14.5 lb*ft of torque for an aluminum head. On the box it says a 1/4 turn of a wrench. I decided to go with 15 lb*ft with lube (anti seize) so I’m likely getting 16.5 ish lb*ft. My torque wrench clicked after about 80-90% of a quarter turn so I’m confident the plugs are not overtightened. I’ve seen people saying to torque to 20 lb*ft which seems excessive. On my GD, the plugs had a nasty tendency to loosen completely so hopefully these will stay in there.

PS: had to buy a new magnetic spark plug socket because of the weird size. I got twelve point (I hate 12 point) because it’s what I could get fast and cheap on Amazon. The inner ring had a weird little metal piece in it (perhaps staking) that makes the plug sit crooked as you can see in the pic. This increases the chance of cross threading so I was careful to thread the plugs with the fingertips of a gloved hand and only an extension. Will return this POS socket for sure for one that is 6 point and better quality.


 
Old Jun 1, 2025 | 11:28 PM
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Unfortunately my borescope battery was drained so I couldn’t get pics of the carbon festival happening inside the cylinders.
 
Old Jun 2, 2025 | 07:11 AM
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Originally Posted by MTLian
I’ve seen people saying to torque to 20 lb*ft which seems excessive. On my GD, the plugs had a nasty tendency to loosen completely so hopefully these will stay in there.
The reason the recommendation went to 20 ft-lbs was because spark plugs in Fits had a nasty tendency to loosen at the original recommendation of (I think) 13 ft-lbs.
 
Old Jun 2, 2025 | 07:51 AM
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Originally Posted by Drew21
The reason the recommendation went to 20 ft-lbs was because spark plugs in Fits had a nasty tendency to loosen at the original recommendation of (I think) 13 ft-lbs.
Yours is a GK?
 
Old Jun 2, 2025 | 09:58 AM
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Originally Posted by MTLian
Unfortunately my borescope battery was drained so I couldn’t get pics of the carbon festival happening inside the cylinders.
Just for fun, here's mine as a stand-in.

 
Old Jun 2, 2025 | 04:22 PM
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Never heard of it, none was loose when I changed them at 100K miles.

This is however, a problem with cylinder #5 on the earlier J-series V6 engines.
 
Old Jun 2, 2025 | 07:12 PM
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Originally Posted by MTLian
I changed my plugs which I’m pretty sure were original after 100k miles. There do seem to be some deposits which would indicate some less than ideal valve sealing. Still, doesn’t look terrible for 100k miles. My car was tending to hesitate in first gear and seemed to get bogged down occasionally after fully releasing the clutch, even with what I consider an appropriate amount of accelerator pedal input.

car seems to cold idle a bit better and it’s still very early but I think the occasional sluggishness in first gear is improved.

Looks like the coil pack bolts have never been removed. The two rusted heads were for cylinders two and three, probably because the py didn’t get the rust preventative oil bath from the previous owner that added oil like it was a champagne shower.
Looks like the coil pack bolts have never been removed. The two rusted heads were for cylinders three & four, probably because they didn’t get the rust preventative oil bath from the previous owner that added oil like it was a champagne shower.

Cylinder 2 coil pack had some noticeable red/terra Cotta looking marks. I wonder what this could be.
Cylinder 2 coil pack had some noticeable red/terra Cotta looking marks. I wonder what this could be. The coils look very clean, I’m doubting these are the original ones from the factory. I like the design with a rubber gasket that fits over the plug hole tube, creating a nice seal against moisture or crud getting inside.

Old plugs, cylinder 1 through 4, from left to right. Electrode gap still looks ok but there are some whiteish deposits on the insulator and the ground electrode, probably from leaky valve seals.
Old plugs, cylinder 1 through 4, from left to right. Electrode gap still looks ok but there are some whiteish deposits on the insulator and the ground electrode, probably from leaky valve seals.
I opted for Iridum IX, lower life but higher performance plugs which I will likely change after 50k kilometers or so.
I opted for Iridum IX, lower life but higher performance plugs which I will likely change after 50k kilometers or so.
Opted for the cardinal sin of antiseize. Internet experts will predict my car will blow up after 500 miles. I’d rather not have to deal with a seized plug. NGK says up to 14.5 lb*ft of torque
Opted for the cardinal sin of antiseize. Internet experts will predict my car will blow up after 500 miles. I’d rather not have to deal with a seized plug. When I removed the plugs, they were in their good. I’d say it took a good 30-35 lb*ft of torque to break em free. I know NGK says not to apply anti seize but NGK will not wipe my tears either if I chowder my aluminum threads due to a seize plug . Also applied some dielectric grease to the ceramic insulator and a bit on the coil boots. Was extra careful not to get dielectric grease on the threads, or anti seize on the ceramic body.

NGK says up to 14.5 lb*ft of torque for an aluminum head. On the box it says a 1/4 turn of a wrench. I decided to go with 15 lb*ft with lube (anti seize) so I’m likely getting 16.5 ish lb*ft. My torque wrench clicked after about 80-90% of a quarter turn so I’m confident the plugs are not overtightened. I’ve seen people saying to torque to 20 lb*ft which seems excessive. On my GD, the plugs had a nasty tendency to loosen completely so hopefully these will stay in there.

PS: had to buy a new magnetic spark plug socket because of the weird size. I got twelve point (I hate 12 point) because it’s what I could get fast and cheap on Amazon. The inner ring had a weird little metal piece in it (perhaps staking) that makes the plug sit crooked as you can see in the pic. This increases the chance of cross threading so I was careful to thread the plugs with the fingertips of a gloved hand and only an extension. Will return this POS socket for sure for one that is 6 point and better quality.
100k is too optimistic . those plugs are not the same at half that distance , i've been replacing mine a lot sooner
 
Old Jun 2, 2025 | 10:36 PM
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My thinking also Bill. That’s why I opted for Iridium IX and will probably replace every few years.

Do people run colder plugs on the GK also? My GD really liked those Denso Iridium power IK22s.
 
Old Jun 3, 2025 | 09:19 AM
  #9  
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Originally Posted by MTLian
My thinking also Bill. That’s why I opted for Iridium IX and will probably replace every few years.

Do people run colder plugs on the GK also? My GD really liked those Denso Iridium power IK22s.
yea , i started using them at 33k miles , the car a had developed some hesitation issues which went away with the new plugs . so , i'm changing them now
at that roughly 33k interval . for me that's about 3 1/2 years . just put in my second set last month . as far as sparks going 100k , years ago i mentioned that
to the mechanic that used to service trucks for the company i used to work for . he told me no way . of course they'll still work , but won't be optimal .
 
Old Jun 3, 2025 | 07:49 PM
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[QUOTE=bill bosco;1489766]yea , i started using them at 33k miles , the car a had developed some hesitation issues which went away with the new plugs . so , i'm changing them now
at that roughly 33k interval . for me that's about 3 1/2 years . just put in my second set last month . as far as sparks going 100k , years ago i mentioned that
to the mechanic that used to service trucks for the company i used to work for . he told me no way . of course they'll still work , but won't be optimal .[/QUOTE

what exact model plug do you use please? Thanks.
 
Old Jun 3, 2025 | 08:59 PM
  #11  
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[QUOTE=MTLian;1489773]
Originally Posted by bill bosco
yea , i started using them at 33k miles , the car a had developed some hesitation issues which went away with the new plugs . so , i'm changing them now
at that roughly 33k interval . for me that's about 3 1/2 years . just put in my second set last month . as far as sparks going 100k , years ago i mentioned that
to the mechanic that used to service trucks for the company i used to work for . he told me no way . of course they'll still work , but won't be optimal .[/QUOTE

what exact model plug do you use please? Thanks.
those were the NGK Iridium IX
 
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