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2013 OBL 2.5
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Discussion Starter #1
After watching several YouTube tutorials and purchasing the necessary tools, I decided to spend this lovely day on spark plugs for my 2013 Outback Limited. I got the car in 2014 with 42k miles on it. I even went to the effort of buying replacement NGK plugs for what I thought would be a change in 5,000 miles as the car now has 55k miles. I saw this effort as more of a dry run to give me the courage to perform this challenging task after overcoming the obstacles of
removing several items blocking my path to the plugs. I have worked on plugs for over 50 years on big American cars. I could typically clean/gap 8 plugs in about an hour - sometimes less if it was not too hot and humid.

Now the Subaru presented me with new challenges. After removing some stuff on the passenger side, I removed the first plug and gapped it. It came in at .034" - definitely smaller than the desired .039"-042" which they should have been. I debated throwing in the new plug, then decided to try my old tricks. So I carefully cleaned the existing plug with a wire brush and single-edge razor blade. I worked very carefully, with almost surgical precision so I would not damage the delicate looking parts of the plug. Then I decided to reset the gap. I have read and heard that these plugs are preset and could NOT be regapped. I reached for my trusty Vise Grip needle nose pliers and after a few attempts, gingerly set
the gap at .040. On to plug number 4 - it was found to be .030" as were the other two plugs. So I repeated my cleaning and gapping for all 4 plugs. I started the car, and noted an improvement at just idle and shut down.

I started thinking about this experience, and realized that 120k mile rated plugs don't make the trip in Outbacks. That is apparently why the dealerships want to do the job at 60k. Now I am wondering what the mileage was when these plugs started changing gaps. I don't know how long they will maintain the current gap, but at least am more informed on what is going on. I typically would have done my plugs procedure at every other oil change on my older American cars, as it was not as difficult a job. For the #1 plug, I kept a battery eliminator on the cables and removed the battery to obtain better access. I also found myself assembling the ratchet, extensions, and sockets at the plug to better reach into the tight locations. Fortunately, the battery eliminator clamps remained in place and maintained all of the car's memories while the battery was out. My most difficult time came when I tried to remove the @2 coil pack from the plug hole. I finally moved it forward toward the @1 plug and the plug-in managed to clear the hole for me. So that's the story. If anyone else has had a similar experience, I would be interested in hearing from you. Don't believe folks when they say that gaps are fixed and can NOT be reset. You just have to use very delicate and tiny movements - and of course, use a gap tool.
 

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2005 OBXT Limited, VF37, STI intake, 5MT
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The "do not gap" is not a "trust-us" type of deal here, it's the microns-thin layer of metal plating that can be disturbed when stressing the base metal (bending the arm to set the gap). When these plugs are "iridium, nickle, rhodium, yttrium", they aren't taking about CNC milled from that material, it's what the spark surfaces are plated with to decrease the wear from high combustion heat, pressure, corrosion and spark arc.

No matter how careful you think you were, you've likely ruined a set of plugs. Clearly they still operate, but I'd expect to change those out in 30k miles or less due to extremely worn electrodes.

Not everything is a planned obsolescence.
 

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2013 3.6R Limited
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700 Posts
^^ What he said. Don't mess with iridium plugs. Just go with the recommended version and leave them alone.
 

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2012 Outback Ltd 3.6r
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335 Posts
Boy, you have it EASY! - With the 3.6, it almost isn't worth the effort to pull them, gap them, and shove them back in. I'm coming up on 66k, and noticed the mileage is down a bit the last couple thousand miles, probably making it time to replace those stinkers. - Not looking forward to the job, having rather large hands, and the clearance, or lack thereof.

I've been quoted anywhere from around $450 to $650 by the dealer and independent shop, so it's going to be me!
 

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2013 3.6R Limited
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700 Posts
When you do your new spark plugs job, please post your findings here. I have size XXXL hands and am not looking forward to this job when it eventually rolls around, so any tips and tricks will be much appreciated.
 

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2010 2.5 CVT Premium
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807 Posts
from what I've seen on these high dollar plugs, the rare earth metal is the last 1/8" of tip and a small pad plated to the overhanging electrode. i.e. a minimum amount of this fancy stuff. So regapping is possible, but be careful with the gauge and how/where one places the gapping tool of choice.

That said, unless these fancy new things behave opposite of physics, the gap usually grows as electrode material is eroded away. If the gap is found to be small, it was small when the plugs first went in.
 

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2018 Outbacks, Grey Premium & Silver Limited
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2011 Outback 3.6R
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52 Posts
I did my plugs yesterday at 50,000 miles (50K of lots of short trips and idling outside of schools and daycares). The car's cold idle is certainly improved. I trusted that the gaps were OK out of the box.

Frankly, plugs are so cheap I don't know why you would try to stretch them to 100K. And not that hard. Yes, harder than an inline 6, but not nearly as hard as my 911. On that I have to set aside a 1/2 day. The 3.6R was done in less than an hour and a half.
 

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2013 3.6R Limited
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700 Posts
So tell us more details of exactly how you changed your 3.6R plugs in less than 90 minutes. Did you work from underneath the vehicle or do it from above? What specific tools did you use? What access tips can you provide? Inquiring minds want to know....
 

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2011 Outback 3.6R
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52 Posts
I went in from the top.

Passenger Side:

1. Remove the airbox, disconnect the MAF.
2. Using a 13mm socket on a 1/4 wrench loosen the coil pack on cylinder 1. Pull out the coil pack. I kept it in the engine bay attached to the harness, but it can be removed if you want to inspect.
3. Using a spark plug socket --> universal joint --> 12 inch extender on a 3/8 ratchet, remove the plug on #1.
4. Replace the plug, torque to spec (usually listed on box).
5. Replace coil pack.

Repeat for 3 and 5.

Drivers Side:

Remove the battery and tray. The only difference for me here was #6 coil pack was hard to remove. I took #4 off the harness, removed the bracket that holds the harness and moved the wires out of the way. Still I had to bend the rubber boot on #6 to get it in and out. #6 probably took me as long as 1-5 combined.

If your hands are too big to get in and unthread/rethread either the plugs, a drill to 3/8 (or 1/4) socket adapter with the right universal and extender will make your life easier. See:

 

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2013 3.6R Limited
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Thanks for your details - much appreciated.

Can you comment on the condition of your original spark plugs at 50,000 miles? My experience with iridium plugs (NGK in our Jaguar cars and Denso in our Lexus SUVs) has been that they easily do 120,000 to 150,000 miles before needing to be replaced.
 

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2013 OBL 2.5
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18 Posts
Discussion Starter #12 (Edited)
Thanks for your details - much appreciated.

Can you comment on the condition of your original spark plugs at 50,000 miles? My experience with iridium plugs (NGK in our Jaguar cars and Denso in our Lexus SUVs) has been that they easily do 120,000 to 150,000 miles before needing to be replaced.
Sure Jon. First, let me thank all of the responders for their input. I appreciate hearing from each of you with your comments. I hope I didn't damage the plugs as I was very gentle with them. I was gentler than my dentist's cleaning assistant. The plugs were all in a dry condition, thus not indicating any oil leakage. They all had the typical brownish cast around the anode and electrode - with some brown on the threads closest to the firing end. I have the OEM replacements and, when needed, plan to replace the originals. I was just very concerned about the loss of gap and still wonder when they started to change. The car is driven easily with most of the mileage being highway miles. My wife has the identical vehicle except hers is a Premium, mine is a Limited, purchased used. Her mileage now is approaching 33k. I plan on pulling a plug on hers to see if the gap is still in the original range or has shifted. FYI, to ease your burden on actually removing/replacing the plugs, I purchased from the NAPA store an extra deep 9/16" x 3/8" six-point socket with no rubber insert. One poster on You Tube advised that when going that route, one needs to purchase from Harbor Freight a small telescoping magnet with a pocket clip to retrieve the plug once it s out of the threads. Works like a charm. When replacing, I just place the plug in the socket and using a small extension or a universal to do the manual turning. I used mainly 1/4" tools, or a 3/8" ratchet. I found myself also using the 1/4" breaker at times. What ate up the most time was experimenting with the various extensions to determine proper fit, mechanical advantage, and clearance. I left the coil pack harnesses in place as I didn't want to disturb or break them. Leaving the plugs undisturbed for years will result in using extra effort to remove them. I once removed plugs from a friend's Geo Metro that had been undisturbed for 5 or 6 years. I finally had to use an 18" breaker bar to ease them out of their aluminum seats. Fortunately, I didn't break anything. In the final analysis, my best advice for improving performance is to do plugs and an oil change. The difference is noticeable immediately!
 

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I pulled a brand new set of Denso Irridiums and measured the gap. Out of the box, every plug was .039. it makes sense that it's the low end of the range, because the gap opens as the plug wears. Assuming you're measuring correctly, then whoever put those plugs in set the gap incorrectly.
 

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2011 Outback 3.6R
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472385


All of the plugs looked like this one. I didn't measure the gap.
Considering we have owned the car 9 years, I expect this will be the only set of plugs that I ever put in it.
 

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2013 3.6R Limited
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700 Posts
Thanks for posting the photo. Looks like changing your plugs was a good idea.

Even at 120,000 miles, the plugs in our Jaguar cars and Lexus SUVs looked much cleaner than what your photo shows.
 

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2018 Subaru Outback Limited 3.6R Crystal White Pearl/black interior
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Thank you for the great explanation on the 3.6R plug removal.
 

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I replaced the plugs in my 2011 2.5 today. About 1 hour, no drama. As expected, the old plugs had opened to .042. I had installed them 50K miles ago with .038 gaps, so they opened as expected. I really think the OP's plugs had been installed incorrectly gapped. Here's what the plugs look like:
472758
 

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2012 OB 3.6R Limited, 2006 LegacyGT
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Thanks for the write-up and info on the 3.6 plug change.... I'm at only 76k but my mileage is pretty terrible and it's one of those things that should be cheap and easy - so I intend to do it soon. Cheap maybe even for 6 iridium plugs. Easy? Nope, not on the modern Subies (I have a 2012 3.6 OB and a 2006 EJ257 Legacy GT). I used to be able to change the plugs on the 90-94 Legacy 2.2 engines in 20 minutes, start to finish, no busted knuckles or weird tools, and perfect torque values.
 
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