14 Forester XT Factory Spark Plugs 77943 Miles

gathermewool

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They all look good to me, except the driver's-side rear porcelain was broken into pieces when I removed it from the socket. All of the pieces appeared to be captured within the socket. It also might be placebo effect, but the engine seems to run better with the new plugs and handle a little smoother with new Motul Gear 300 diff fluid front/rear, replaced two days before the plugs. I felt no difference after changing the diff fluid in the Legacy (no plug change yet) [Linked Image] [Linked Image] [Linked Image] [Linked Image] [Linked Image]
 

gathermewool

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Originally Posted by Propflux01
That's not much of gap, my lawnmowers is bigger!
It's not. The gap is nearly double for my NA Legacy, IIRC.
 
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Which engine are you running? I have a 17 OB 3.6. I'm at 74k miles. I've seen a decent number of the Subaru's plugs look pretty good around the 70-100k mark. I'm going to do mine at 100k. I also don 't idle much and 70% is highway for me.
 
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Gather you likely broke that plug, pulling it out, by cocking the socket. The factory had a straight shot with the engine out of the car. Odd to see what looks like MMT or ??? on the insulators. Those plugs should fire with the mini coils at 0.8mm. That gap is too tight FUJI H.I. My manual on my NA FB20 wants to change plugs at 60K and these are the even longer lasting Ruthenium. With the lean burn fingernail GND. No way, Jay. First do no harm ... It's running fine leave it. Not a easy job to do perfect - as plugs require. Well there goes my free "limited lifetime" extended powertrain warranty. Taking them out may do more harm than good.
 
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plugs can look good but perform less than optimal!! pulled girlfriends out at 50 thou looking good, new plugs increased mpg by 3 + or -. penny wise but dollar foolish, they are out put new ones in!! that broken one looks to be oily
 
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I got new plugs in my '14 FXT while it was in at the dealer for the LSPI recall at 40kmiles...the shop called me and said they looked "OK" but recommended a replacement anyway, when they said it would just be at part cost since they were already in there I jumped on it. Think they charged me $80-100, which sounded about like what a dealer would charge for 4 modern plugs...would guess they would be more like $40 or maybe even less if I tracked the plugs down myself. One of the plugs that came out then had cracked insulation, but not nearly as bad as the one shown in the pic above. I read at the time that insulation damage could be a sign of LSPI occurrence...lots of people in that recall also had severe electrode damage to their plugs that was also considered likely to be related to LSPI events. I asked for the plugs to be kept and they looked kinda crummy to me, I really didn't know how to judge them for functionality but I was glad new ones were put in then. I had those plugs replaced at 100kmiles to stay on the recommended 60kmile maintenance timeline. Is it just a trick of the camera, or is the one with the cracked insulator also much dirtier on the business end than the other plugs? How tough was the job of replacing them? I was reading up on this as a do it yourself job for the FXT and one source recommended to loosen the boxer engine from its mounts and tilt it a bit to make one or two of the plugs more accessible...that was the point where I decided to stick to changing oil and filters, trying to clean my intake valves (which I have made a mess of more than once), and upgrading easy things like the rear sway bar.
 

gathermewool

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Originally Posted by BISCUT
Which engine are you running? I have a 17 OB 3.6. I'm at 74k miles. I've seen a decent number of the Subaru's plugs look pretty good around the 70-100k mark. I'm going to do mine at 100k. I also don 't idle much and 70% is highway for me.
The one in my sig - FA20DIT I thought about and researched about when to change plugs in both of my Subies for a long time. Like you and many others online, I couldn't get over the disparity between NGK's recommendation of 80k-100k miles and Subaru's spec of 60k miles, which has been around for as long as Ir plugs have been around, AKAIK. It could be that Subaru is just lazy and hasn't done any research whatsoever into whether these plugs can go longer. It could be a flub on Subaru's part, just as when they have and still spec 5W-40 conventional oil as OK for top-offs. It could be that Subaru did their testing and truly found the Ir-tipped plugs to be nominally good for 60k miles. Maybe they are good for 80k-100k miles, but found a disconcertingly high proportion of engines were having issues at the 60-80 mark to warrant the spec. Who knows! In the end, the job sucks but isn't too expensive, so I've decided I'll try to change between 60k-80k miles from now on. With that said, I've got the plugs for my Legacy with ~ 55k miles and may just change them now to get it out of the way...that, and I've still got all of the tools out from the Forester swap.
 

gathermewool

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Originally Posted by ARCOgraphite
Gather you likely broke that plug, pulling it out, by cocking the socket. The factory had a straight shot with the engine out of the car. Odd to see what looks like MMT or ??? on the insulators. Those plugs should fire with the mini coils at 0.8mm. That gap is too tight FUJI H.I. My manual on my NA FB20 wants to change plugs at 60K and these are the even longer lasting Ruthenium. With the lean burn fingernail GND. No way, Jay. First do no harm ... It's running fine leave it. Not a easy job to do perfect - as plugs require. Well there goes my free "limited lifetime" extended powertrain warranty. Taking them out may do more harm than good.
I figured as much. That one was the hardest to get to and, with the angle, required the most care. Maybe I got a little lax in ensuring the socket was fully seated at ALL times. I just figured it was odd since I've never seen it before.
 

gathermewool

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Originally Posted by benjy
plugs can look good but perform less than optimal!! pulled girlfriends out at 50 thou looking good, new plugs increased mpg by 3 + or -. penny wise but dollar foolish, they are out put new ones in!! that broken one looks to be oily
What vehicle was this in? What was the spec'd change interval?
 

gathermewool

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Originally Posted by Virtus_Probi
I got new plugs in my '14 FXT while it was in at the dealer for the LSPI recall at 40kmiles...the shop called me and said they looked "OK" but recommended a replacement anyway, when they said it would just be at part cost since they were already in there I jumped on it. Think they charged me $80-100, which sounded about like what a dealer would charge for 4 modern plugs...would guess they would be more like $40 or maybe even less if I tracked the plugs down myself. One of the plugs that came out then had cracked insulation, but not nearly as bad as the one shown in the pic above. I read at the time that insulation damage could be a sign of LSPI occurrence...lots of people in that recall also had severe electrode damage to their plugs that was also considered likely to be related to LSPI events. I asked for the plugs to be kept and they looked kinda crummy to me, I really didn't know how to judge them for functionality but I was glad new ones were put in then. I had those plugs replaced at 100kmiles to stay on the recommended 60kmile maintenance timeline. Is it just a trick of the camera, or is the one with the cracked insulator also much dirtier on the business end than the other plugs? How tough was the job of replacing them? I was reading up on this as a do it yourself job for the FXT and one source recommended to loosen the boxer engine from its mounts and tilt it a bit to make one or two of the plugs more accessible...that was the point where I decided to stick to changing oil and filters, trying to clean my intake valves (which I have made a mess of more than once), and upgrading easy things like the rear sway bar.
I had the same check done, obviously, but all was well - no change of plugs required. It sounds almost like they did the same thing I did, damaging the insulation, but talked you into paying for new plugs, whereas they needed to be replaced due to the damage anyway! I had one LSPI more than a year AFTER this check and ECM update. I was getting onto a highway onramp and floored it and heard KNOCK KNOCK KNOCK... and then it felt as if it lost all power. Luckily the road was clear. I was in no position to pull over, so I just gently accelerated, which it did just fine. No other issues since then! I was on the factory tune then, btw. I'll check the business end of the broken plug. You'll notice that it's facing the opposite direction of how I was holding it for the initial picture of the electrodes.bo Job complication: this job sucked compared to my previous STI, '97 Legacy GT and was obviously WAY harder than any inline-4! I think a 1/4" drive ratchet with EXACTLY the right length extension might have helped for the forward two plugs; however, they weren't very hard compared to the rear plugs. I should also have jacked the engine up from the oil pan to give me a little room. As it was I could barely get the driver's-rear coil pack off. I was actually so mad about that plug that I forgot to add a dab of dielectric grease to only that plug. duh -----I'm expecting the change for the FB25 to be little easier. It looks as if there's just a fraction of a bit more clearance than the FA20DIT. I'll let you guys know. My new endlinks just came in, so I'll be changing the RSB on the FXT this weekend. That is, if I can get a good enough grip with some vice grips to get the top nut off!!! Stupid hex stud strips way too easily. I was lucky to do this job on my Legacy soon after it came up from North Carolina, where I bought it used. Everything was pristine - no rust
 
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Yeah, I did the RSB when my FXT was pretty new and not yet rusty. It should have been very easy, but I made it into an adventure due to my lack of wrenching experience. I loved the improvement on dry pavement, felt like maybe it made the FXT just a bit more prone to slide in snow and ice but I am just trying to keep the speed up enough to make sure I have forward progress in those conditions, anyway. I can't imagine trying to change that thing now after 5 years/115,000 miles and our New England winter salt conditions.
 

gathermewool

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Originally Posted by Virtus_Probi
Yeah, I did the RSB when my FXT was pretty new and not yet rusty. It should have been very easy, but I made it into an adventure due to my lack of wrenching experience. I loved the improvement on dry pavement, felt like maybe it made the FXT just a bit more prone to slide in snow and ice but I am just trying to keep the speed up enough to make sure I have forward progress in those conditions, anyway. I can't imagine trying to change that thing now after 5 years/115,000 miles and our New England winter salt conditions.
I knew I was screwed as soon as I put in the correctly-sized hex key and it wouldn't fit, there was so much rust. a 4.5mm fit seemingly perfectly, but rotated as soon as I turned the wrench...THEN the 5mm fit perfect...and THEN the 5.5mm until it was fully rounded out. This was the driver's side rear link; the passenger side, as you might guess, produced similar results! At this time I knew I would need new links and so had them on hand before continuing to make a bad situation worse. I still wanted to try to get the old links off, even though it was a moot point by the time I had the new links, since I'd never re-install the old bar nor be able to sell it, so the old links could remain attached from the top for forever for all I cared. Even with the largest vice grip I could get on there, and after multiple positions and attempts, the driver's side rear link would NOT come off, with several threads still exposed! I was, however, able to get the passenger-side link off. Both link's boot was ruined in the process. I don't plan on ever removing the new RSB, but did add the smallest dab of silver moly anti-sieze to the threads of both ends of the links, as well as the bracket fo the bushings, just in case.
 

gathermewool

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I looked at all of the plugs more thoroughly and the dark look of the plug with the broken porcelain was just a shadow. It is a little bit darker on that side opposite what's picture in my hand above, but not nearly as dark as it look laying on the cardboard.
 
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Originally Posted by benjy
plugs can look good but perform less than optimal!! pulled girlfriends out at 50 thou looking good, new plugs increased mpg by 3 + or -. penny wise but dollar foolish, they are out put new ones in!! that broken one looks to be oily
I am not as cheap as far as purchasing new parts , as I was when I was younger and had a young family to support . Now a days , I try to source parts before I start wrenching , so I do not have to make a quick trip to the parts store . This also allows me to sometimes find better pricing , online . So , If I remove the part , I usually replace it with new . We had a 1996 Chevy Lumina Sedan with 120000 - 140000 miles on it . It was running a little rough . Replaced plugs , a very big pain on the rear bank , against the fire wall . Ran a little better , but eventually discovered it had a damaged wire going to the crank shaft position sensor . But I was glad I replaced the plugs .
 
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