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Changing spark plugs on my 95 Legacy


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26 replies to this topic

#1 reeze

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Posted 04 March 2009 - 09:27 AM

This is a follow up to my earlier thread about my 95 Legacy FWD with 205K running rough:

http://www.ultimates...ead.php?t=96568

First, if anyone has followed that thread, let me say that this morning I am returning the aftermarket wires and Bosch plugs. I will be exchanging the plugs for NGKs, and going to a local dealer to buy the OEM wires.

Now, although I am a total amateur when it comes to auto repair, I have in my lifetime replaced spark plugs. But, after googling a bit and reading about some issues, I'm a little concerned about whether it might be wiser to let a real shop do this. I don't have a torque wrench, just a craftsman rachet, spark plug socket and 3" extension bar. Also, I've read that there could be issues in removing spark plugs that have not been changed in a LONG time from aluminum block engines. It's possible that the old plugs have been in there for a REAL LONG time (I'm ashamed to say how long!). Also, there is mention of using anti-seize compound on the new plugs, however I couldn't find out by googling whether that advice is correct for this particular engine.

As I said, I've done this before, at least a few times, on my two previous Legacys ('90 and '92), and maybe I just got lucky; I think I just tightened the plugs until I felt the gasket start to crush, then torqued it a bit more until I started feeling some real resistance, then stopped. I suppose I could buy a torque wrench and it would cost me less than what a shop would charge to change the plugs & wires, so that might be an option. Another complicating factor is that I would be doing this job in 35 degree weather :( (which is better than if I tried it yesterday in 17 degree weather!!).

As always, thanks to the experts here for their guidance!!

#2 bratman18

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Posted 04 March 2009 - 09:29 AM

I have never used a torque wrench while installing new plugs, you will be fine, if you've done it before, you'll be able to do it again. It's very straight forward.

#3 reeze

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Posted 04 March 2009 - 09:46 AM

I have never used a torque wrench while installing new plugs, you will be fine, if you've done it before, you'll be able to do it again. It's very straight forward.

Thanks. Do you use anti-seize?

#4 Rooster2

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Posted 04 March 2009 - 09:53 AM

I have never used a torque wrench to tighten plugs. Just snug 'em up tight, but don't crank down to try to super tighten them.

Your 95 Leggie will have the 2.2 motor, which give a little more room to change plugs, vs the 2.5. You may want to purchase a stubby 3/8 drive extension that is about an inch and a half long. The shorter extension helps in tight spaces.

Recommend using antisieze on the new plug threads. It helps to lube in rethreading the plug into the head, and also helps to prevent gauling (plug won't loosen) the next time you change plugs. Suggest hand tightening the plug first, before using the drive. You don't even want to think about the consequences of cross threading a plug.

I have had a good experience with Bosch ignition wires and plugs. Yea, the cheapie wire sets from the discount car part stores are not a good idea for Subie use IMO.

#5 heartless

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Posted 04 March 2009 - 10:09 AM

personally, i have never used a torque wrench or anti-sieze on my plugs, altho the anti-sieze may not be a bad idea - doesnt require a lot, just a thin coating.

hand thread the new plug until you hit "bottom" - plug should turn easily, if it doesnt, DO NOT force it!! - then use your wrench to snug up about a 1/2 - 3/4 turn or so - no need to really crank them down - thats where problems occur.
a little trick i use to start plugs correctly is to turn the plug backwards (as in removing) with very slight pressure, until i feel it "pop" into the threads - (this also works well for fasteners that are easily stripped - like screws into plastic...)

if you run into a problem removing the old plugs - give a small squirt of PB Blaster to the plug hole, hook your wires back up and run the car for a few minutes to warm it up a little - be careful not to burn yourself, but try removing the plug when it is still warm, should be easier.

Good luck

#6 johnceggleston

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Posted 04 March 2009 - 10:24 AM

as a scared rookie, i removed and replaced one plug at a time. disconnect one wire, remove the plug, install the new one and then the new wire. this way if i had a problem i still had the other 3 in good working order, and if i had to drive it to the shop i could. but you won't have to.

you can also just do the wires first, one at a time, and see how it drives, just for grins. but then you'll have to wait for the engine cool off to proceed.

good luck, even if you have to buy a ratchet extention, you'll save big doing it yourself.

#7 reeze

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Posted 04 March 2009 - 12:01 PM

As always, thanks to everyone for the words of wisdom. I just returned from the Subie dealer with the OEM wires, exchanged the Bosch for the NGK plugs, and also stopped at Sears to buy a spark plug socket (the one I had, 11/16", was the wrong size). Also, there was a set of four extension bars on sale at half price ($10 vs $20) so I picked those up too, I'm sure they'll come in handy down the road.

I'm off to start the job...just hoping the old ones come out easy. The engine is still warm, that might help.

#8 reeze

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Posted 04 March 2009 - 02:22 PM

Done! Success. At least the idles smoothly, I'm off to pick up my daughter at her school.

Thanks again to everyone for the tips. I may post a picture of the old plugs, one of them looks different from the other three. Maybe some clues as to what else is going on.

#9 crash321

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Posted 04 March 2009 - 02:24 PM

I'm off to start the job...just hoping the old ones come out easy. The engine is still warm, that might help.


Bad idea to remove plugs in a hot engine with aluminum heads. Make sure it is cool before removing plugs otherwise you may end up with aluminum filings filling the threads of the old plugs. Edit posted to late glad it went well.

Edited by crash321, 04 March 2009 - 02:26 PM.
..


#10 reeze

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Posted 04 March 2009 - 04:40 PM

Crash321: the engine was only slightly warm by the time I did the plugs.

I'm back from my afternoon carpooling & errands, after driving about an hour, stop & go and about 30 miles of highway driving. Unfortunately I had one slight incident of the rough running that started me on this whole adventure. It lasted about 30 seconds. Looks like I have a little more work to do.

Just to reiterate from my previous thread, last week the car started running rough and stalled once, as I was climbing a hill. A few days ago I went to Autozone to have my codes read and they were:

P0420 -- cat converter or O2 sensor issue
P0400 -- EGR system (blocked, or failed EGR valve)
P0303 -- misfire in cylinder 3

I figured the misfire was the most direct cause of the rough running so I was hoping the new plugs & wires would fix it. Not sure if the cat converter issue is related to misfiring or rough running (the Autozone printout says the misfiring can CAUSE the P0420 code). The EGR system might be the next thing to look at, however I don't think this is a DIY job (for me at least). I was thinking of replacing the fuel filter and PCV valve next since they are probably due anyway and I think I can handle that (unless the fuel filter is unreachable to someone without lifts).

I may start looking at available Legacys...

#11 Rooster2

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Posted 04 March 2009 - 05:48 PM

If it were me, I would install a new PCV valve and fuel filter. Both are easy under the hood installs, and cheap products to buy at a parts store.

Did your "roughness" start after a gas fill up? It is possible that you got a bad tank of gas, that has some water in it. If so, I would add a can of "dry gas" to your tank to see if that helps

#12 reeze

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Posted 04 March 2009 - 06:13 PM

If it were me, I would install a new PCV valve and fuel filter. Both are easy under the hood installs, and cheap products to buy at a parts store.

Did your "roughness" start after a gas fill up? It is possible that you got a bad tank of gas, that has some water in it. If so, I would add a can of "dry gas" to your tank to see if that helps

Thanks Rooster 2, I will do those two parts next, hopefully tomorrow.

Yes, bad gas was my first thought. But the initial experience didn't start right after a fill up, it was a few days later, so that's probably not the cause. In any event, I filled the tank again and added a can of dry gas since that time.

#13 3Pin

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Posted 04 March 2009 - 06:51 PM

Make sure the vacuume lines arer clear from begining to end. I used to get a rough idle and P0400's up the ying yang until one day I got fed up and started replacing vacuume lines that were older. One of lines had about 6 drops of oil in it. Once I replaced it and reset the CEL, it never came back.

Cheap troubleshootign step. On a different outback I had, it was the egr valve and nothing to do with the vacuume lines. Best of luck!

:banana: :banana: :banana:

#14 The Dude

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Posted 04 March 2009 - 07:25 PM

I respect the opinions from posters that tightening spark plugs by hand is their normal practice. I have tightened many spark plugs by hand as well.

BUT, I really recommend getting a torque wrench if you're going to do the job. A little too tight, and you may strip the threads. A little too loose, and the engine may "spit" the spark plug out, damaging the threads. It's well worth the cost of a torque wrench for the piece of mind.

Also, you'll want a piece of washer hose. I've never worked on the DOHC engine, but I'm pretty sure that you'll be needing a number of extentions and swivels. You're going to be removing the washer reservoir, I think, and maybe several other things.

Is this the DOHC 2.5L "Phase I" engine? Because if it is, the DOHC has a reputation as being a difficult engine when it comes to replacing the plugs. In fact, Subaru speced long life platinum sparks and a 60,000 mile
replacement interval just because the plugs were such a PITA to replace.
When the SOHC 2.5L "Phase II" came out, regular spark plugs were speced, and the replacement interval went to 30,000 miles. So, if you have the DOHC 2.5L, be aware that you'll be learning to swim on the deep side of the pool.

#15 crash321

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Posted 04 March 2009 - 07:32 PM

I
Is this the DOHC 2.5L "Phase I" engine? Because if it is, the DOHC has a reputation as being a difficult engine when it comes to replacing the plugs.


He has two threads going, it is a 2.2

#16 The Dude

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Posted 04 March 2009 - 07:35 PM

Congratulations! Sounds like your car has the 2.2L, a very mechanic friendly engine.

Edited by The Dude, 04 March 2009 - 07:38 PM.


#17 reeze

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Posted 04 March 2009 - 09:27 PM

Congratulations! Sounds like your car has the 2.2L, a very mechanic friendly engine.

When I bought this car 5 years ago, I specifically looked for a Legacy with the 2.2 engine because I heard it was very reliable, and I read that the 2.5s had head gasket issues.

To do the plugs I had a swiveling rachet, a 3" "wobble" extension, and four other extensions ranging from 1 inch to about 8 inches long. So I was pretty well covered. Still, the spark plug nearest the driver (sorry, don't know cylinder #s!) was a bit@h to do because of the hoses and wires around it, and the windshield washer reservoir. Of course this engine compartment probably looks empty compared to the newer Subies :).

#18 reeze

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Posted 04 March 2009 - 11:23 PM

Make sure the vacuume lines arer clear from begining to end. I used to get a rough idle and P0400's up the ying yang until one day I got fed up and started replacing vacuume lines that were older. One of lines had about 6 drops of oil in it. Once I replaced it and reset the CEL, it never came back.

Cheap troubleshootign step. On a different outback I had, it was the egr valve and nothing to do with the vacuume lines. Best of luck!

:banana: :banana: :banana:

I know this makes me sound real stupid, but I am not at all certain of exactly which hoses are for vacuum. Also, are they a standard size (inner or outer diameter) that I can just buy a few feet of and cut to size as needed? I see LOTSA hoses in that engine compartment!

#19 crash321

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Posted 05 March 2009 - 07:50 AM

I know this makes me sound real stupid, but I am not at all certain of exactly which hoses are for vacuum. Also, are they a standard size (inner or outer diameter) that I can just buy a few feet of and cut to size as needed? I see LOTSA hoses in that engine compartment!


They are the ones that are the smallest rubber hose usually going to an actuator, they are about the size of a pencil (maybe a little smaller) and is pretty much standard size with the exception of your brake booster vac line. Yea, buy two to three feet and cut as needed:)

#20 davebugs

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Posted 05 March 2009 - 07:58 AM

For vaccum line size (all but the brake booster) get the size that goes to the gizmo on the passenger side strut tower, or to the charcoal canister on the pass side "framerail" up by the radiator. It's all the same size.

#21 reeze

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Posted 05 March 2009 - 09:15 AM

Thanks Crash321 & Davebugs, I'm off to the parts store.

#22 reeze

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Posted 06 March 2009 - 03:06 PM

This morning I replaced the fuel filter and PCV valve. Just got back from about 1.5 hrs of driving, stop & go around town and a stretch on the highway. Not a hiccup. The engine sounds like a purring cat when I'm idling. I'm keeping my fingers crossed! Thanks again to everyone that took the time to post to my two threads and help me!

#23 Olnick

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Posted 06 March 2009 - 03:36 PM

The engine sounds like a purring cat



Yup! Sometimes it's just the little things. Keep up the preventive maintenance and you'll be good for a long time.

Congrats!

#24 unibrook

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Posted 06 March 2009 - 03:44 PM

reeze, if your hesitation prob comes back, your next usual suspect should be the front 02 sensor if it hasn't been changed in the last 40k miles. That cured the problem for me...2001 Forester. Phase 2 2.5 SOHC.

#25 reeze

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Posted 06 March 2009 - 04:03 PM

reeze, if your hesitation prob comes back, your next usual suspect should be the front 02 sensor if it hasn't been changed in the last 40k miles. That cured the problem for me...2001 Forester. Phase 2 2.5 SOHC.

Thanks. This sensor has not been changed since I bought the car, 5 years ago, with 60K miles. Now I'm at 205K!

I remember looking into this at one point this past week. It's screwed into the exhaust manifold, correct? Chances are it needs more than a rachet or box end wrench to get out, as long as it's been there!

Edited by reeze, 06 March 2009 - 04:10 PM.





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