sixonemale

Mandy,

The plugs look pre-gapped, were they? I recently had plugs changed on another vehicle and even called the manufacturer of the car and plugs and they both said they were pre-gapped plugs and therefore, just install, no gapping necessary. They were wrong, the car ran horrible after the mechanic installed them. I took each one out, gapped it to spec, and reinstalled all of them and the car ran great.

Thanks

mandyfig

Yes they are pre-gapped. These things are almost common from platform to platform. It is quite good they are pre-gapped.

I will not touch them if I have to deal with calibrated shims and adjust the gap, that's way too far back many years, LOL.

But I have put this off for a long time, turns out it is quite an easy job, but as usual due dilligence required so that you do not mess up anything along the way.

sc2002

Thanks Mandyfig for posting valuable pictures,tips, and procedures to change the sparks plugs for your SC.

I am in search of the location of my O2 Sensor (Oxygen Sensor) for my SC, particularly the Bank 1 Sensor 1. Do you or anybody know the location of it in one these posted pictures? Or know how to get to it, either from top or bottom of the SC ? Thanks for your help.

Harold57

sc2002, do a search on this forum. VVTiBob posted a diagram of where the sensors are a while back. It shouldn't be too hard to find.

Welcome to the forum, BTW.

mandyfig

I must say that I do feel a better running engine after the plugs replacement. Smooth and responsive.

kjcole

OK, just changed my plugs - went with the Denso OEM Iridium long-life. Took about 1 1/2 hours but I wasn't in a hurry. An assortment of wobble-type extension bars are a must. 123K miles on the clock, but I'm the second owner so I don't know if the plugs are original (NGK Iridiums OEM were in it). Plugs had started to show deposits building up forming 'shoulders' on the center electrode. Engine was starting to idle just a little rough (some vibration showing up in rear-view mirror). Absolutely smooth now. Interestingly, for torquing Denso says finger tighten until the washers are snug, then give it another 1/16 turn. That's not much!

mandyfig

NGK showed in the box where you hand tighten and then move 1/3 to 2/3 max. Need to make sure the crush washers are "crushed-seated."

chrisv78

Thanks for the great DIY. I went out this morning, took out the battery, and then stared down at the tangle of tones associated with the air box and what I think is the mass air flow sensor system. Unfortunately I could not figure out how to remove these pieces and the plastic bracketry covering the #2 plug on the passenger side. I found a fairly long bolt and was able to remove the small and large hose from the air cleaner, but that was it. Any help would be appreciated.

mandyfig

I do not remember in detail however I know that it is straightforward. I did my Cold Air Intake a long time ago, way before I did the Plugs, so it is a blur.

Do not be afraid to go for it. It is not that bad. Go follow the manual if you have it. Otherwise I will look at my manual and will post it here.

mandyfig

This should show all the connections you need to take off and replace. Hope this helps. Let me know what is the challenge and if needed take a picture and will help.

chrisv78

One of the spark plugs is hiding behind the plastic assembly just to the left of the [22-224 notation on your picture. I thought it was a bracket that had to be removed, but this picture looks more like an entire assembly of some kind. There are a connector and three hoses are connected to it, as well as a bolt and large air hose. I tried jiggling it to see if it was free before using more muscle, but it was very tight so I figured there had to be another bolt somewhere. I was also having trouble with the large hose as well as it wouldn't budge for me at the manifold. I guess a little more muscle will be needed.

Thanks

mandyfig

Yes the entire assembly has to be taken out. Since I had a Cold Intake Air installed the, all of what you see in the diagram got removed. Take your time. Good luck.

sixonemale

Mandy, great thread! Brief question, what is the difference between the NGK 4589 and the DENSO 5304 spark plugs? Are they essentially the same spark plug? Also, which one is OEM? Thanks in advance of comments or answers.

mandyfig

I believe the manual specifies both a Denso and an NGK Laser Iridium plug. I got the NGK ones. You can go to the Denso and NGK website and plug in our SC and it will specify the OEM replacement.

mandyfig

Back from the archive...I had to make a correction on the NGK Plugs I used: 4589 (used to be 3589, w/c is wrong).

The Plugs I used: NGK IFR6T11 Stock 4589 Laser Iridium Premium