[srpotter]

This is my first and will probably be my last attempt to change the dreaded #6 plug on the 3.3L V6.

First off I did my research, read the sticky on the #6 plug removal and removed the hood, used u-joints, extensions... you know the story. The ceramic on the old plug broke off while I was removing it so I carefully used my handy bore scope camera and a brush to clean the debris before I put the new plug in.

This is where the frustration begins! for the life of me I cannot get the [email protected]$n thing to thread properly! I tried for close to 5 hours last night with no luck. It feels like it wants to thread in but gets jammed up after maybe only one turn. I am super scared of cross threading this thing so tonight I am going to borrow the neighbors air compressor and blow out any reaming debris for the threads and hopefully that helps.

If that does not work the only other thing I can think of is removing the upper manifold to hopefully gain more access. Is removing the upper manifold enough or would I have to remove the lower too.

Thoughts? this has me super frustrated!

 

[TexasScout]

You really need to "chase" those thread with a tap. You can usually get one at the AP store. Smear it with grease first so it picks up the chips.

 

[jon_bransford]

My last truck had three plugs that were seized and could not get them to thread back in.
Took it to a buddy's shop and tack weld them in.



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[srpotter]

You really need to "chase" those thread with a tap. You can usually get one at the AP store. Smear it with grease first so it picks up the chips.

Auto Zone has a thread chaser in stock that looks like it would work. From what I am seeing online the threads on the truck look to be M14x1.25. I compared this to the threads on the new spark plugs and they appear to be a perfect match. Can anybody else confirm that this is the correct thread size?

 

[smj999smj]

Yes, that's the size.

 

[srpotter]

Bought the thread chaser, smeared it with anti-seize and was unable to get it to thread. It would catch then pop back out. Looks like I will be taking the upper and possibly lower manifold off to fix the issue. Any other suggestions?

 

[TexasScout]

One last thing, go to a welding ship and get a 1/2" spiral wound metal brush and clean that hole out good.

 

[Cusser]

Disclaimer: I've only done this job once, on my daughter's 1998 Pathfinder with same engine (my 2 Frontiers are 4-cylinder). I did not remove the hood on that Pathfinder to change the plugs though; took me like 1.25 hours to do all six, and for me the toughest part was getting the spark plug wire ends off the spark plugs, and I have a puller tool. I did use a little mirror, flashlight, and two 3-inch extensions to get to the #6 plug, remember using my left hand on the ratchet wrench - because I had to, for clearance (I was laying across the engine for this one).

I do like the thread chaser idea, used one on my neighbor's Toyota after he fussed for 5 hours trying to thread in a plug, took 5 minutes. My guess is that you don't have the plug or the thread chaser exactly parallel to the threads/aligned properly; it's not that easy to get it straight, the plug is in at an angle, not straight up and down.

Have you thought about towing the truck to a mechanic who would be more experienced?

 

[srpotter]

Well... I had the truck towed to a local mechanics shop. I hope to hear back soon on what they say. I will keep you posted.

 

[FrontierSE4x4]

Sorry about your luck. I remember that one being a bear. I did take the hood off my truck because it gave me a little more access to the incredibly small and cramped space where that plug is located. I used a series of extensions and just kind of felt around until I felt what seemed like the threads. Slowly turned it until it felt tight and the plug was secure. Poor design from the factory.

 

[smj999smj]

Knowing how bad the VG33E plugs were to replace, I figured the VG33ER would be a lot easier because of having the supercharger rather than the VG33E's upper plenum in the way. Boy, was I wrong! The only good thing...if one could say it was that...is that I had to remove the supercharger to replace the fuel injectors, so it was a great time to do plugs and wires and throw a new fuel pressure regulator in while I was back there!

 

[RedDR]

Yeah, it's a real bear. That engine is really crammed into the truck.

 

[Cusser]

The good thing is that plugs these days last like 100K.

I did read on this site that some figure if the first 5 plugs don't look too bad, that they just "forget" the #6. I didn't do that, figured it was a challenge to myself, and I had read the posts on this forum. So I got out an old towel, laid it over the engine, laid down on that and was careful not to break any fasteners or anything on top of the engine. My daughter had been experiencing lack of power going up hills in that 1998 Pathfinder, so I felt it was important there to change all 6, even though the plugs did look pretty good (had no idea if they had been changed previously, and if so: just 5 or all 6).

The power issue wasn't helped by the plug change, the issue I found a year later was a faulty distributor. So runs good now; even 2 shops could not diagnose lack of power to a faulty distributor; so either its coil or its advance likely faulty.

 

[TexasScout]

I had mine done at the dealer.... no sweat.

 

[das boots]

With my recurring lower back problems, I know I was not able to do the #6. Thank you independent shops that cater to Japanese vehicles. I provided the plugs, they did the labor.

 

[kevinjohnson3216]

It's much easier with the hood and upper plenum off, thats when I did mine and I upgraded to NGK iridium so I won't have to do them for quite a while, they last longer than platinums

If you're going to chase the threads then I would take off the upper plenum - expect to replace coolant and vacuum hoses , clamps... and have a razor blade ready to cut off stuck hoses!

Also a new upper plenum gasket

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[smj999smj]

It's much easier with the hood and upper plenum off, thats when I did mine and I upgraded to NGK iridium so I won't have to do them for quite a while, they last longer than platinums

Well, it depends which Iridiums you put in. Most put in the Iridium IX, which is the "economy" iridium plug and is only rated for 60,000 miles; it has a single iridium electrode. The OE Iridiums are a double iridium electrode plugs and will last over 100,000 miles. The Iridium IX is to the OE Iridium as is the G-platinum is to the Laser Platinum plugs.

 

[kevinjohnson3216]

Well, it depends which Iridiums you put in. Most put in the Iridium IX, which is the "economy" iridium plug and is only rated for 60,000 miles; it has a single iridium electrode. The OE Iridiums are a double iridium electrode plugs and will last over 100,000 miles. The Iridium IX is to the OE Iridium as is the G-platinum is to the Laser Platinum plugs.

Shoot, I put in the NGK iridium ix from rockauto thinking they were top notch plugs! You burst my bubble.

NGK only sells the ix on rockauto, I'd have to do with denso for what looks to be OE iridium? I thought NGK plugs were best - is denso best in this situation??

Thanks


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[smj999smj]

No, I would stick with what you have in it, but plan on changing them out around 60000-70000 miles. NGK doesn't make their OE Iridium plugs for the VG engine. The best plug as far as longevity for the VG is the Laser platinums, which will last 105,000 miles. Iridium is a denser metal than platinum, which is why they started using it. As far as performance, you wouldn't notice any difference between the two in a stock engine. A good example is the VQ40DE engine. They originally came with the NGK Laser platinums and around 2008 they switched to the OE Iridiums. At the time, the iridiums were around $18-$22 per plug and almost impossible to find at the auto parts store whereas the Laser Platinums could be had for $10 and found locally. The NGK catalog even listed the Laser Platinums as the factory plug on the 2008, but when I pulled out my original plugs on my 08 Pathfinder, they were the OE Iridiums. I had already purchased Laser Platinums, so I put them in. There was no change in performance nor gas mileage. Interestingly, where GM has AC iridium spark plugs that are made by NGK in some of their vehicles and rated for 120,000 mile intervals, Nissan still rates the OE Iridiums for 105,000 miles, just like the Laser Platinums. However, if you pull an OE Iridium out of a VQ engine with 105,000 miles on it, you will see that the wear is pretty marginal and I would expect to get 120,000 miles out of them without any issues.
Denso plugs are pretty good, as well, and they are owned by Toyota, which uses both Denso and NGK plugs in their vehicles. Personally, I used Denso iridium plugs in my Tacoma, when I had it, but everything else I've owned has had NGK spark plugs. That includes my Nissan vehicles, my Honda lawn mower engine, my Briggs & Stratton lawn mower engine, my chain saws, leaf blower...you name it! They're the best plugs for my money.

 

[das boots]

I guess I will replace my NGK Iridiums when I hit 210K.