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97 OBW, changing plugs


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13 replies to this topic

#1 opus

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Posted 13 May 2004 - 01:21 PM

It looks to me like spark plugs go on the end of the 4 wires that come from the coil. I think I must be wrong though....a human couldn't fit their hand where the plugs should go. :-\

Tell me, must I remove the fenders, tires to change the plugs? I cant believe what this looks like. Tell me there has to be an easy way to do this. It dertainly doesnt look as easy as my '63 pickup.

#2 frag

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Posted 13 May 2004 - 02:11 PM

I presume you have a legacy.
Then you have to remove the engine to replace the spark plugs. That's why only wrench heads and he-men not to say nut heads buy Subarus.
More seriously, most of us here have done this one or more times.
On the passenger side, unsnap the air filter box and put it aside (check that no vac hoses or other hoses have come apart at the joints when you replace.
On the driver side, unfasten the washer fluid reservoir (two bolts: use penetrating oil and be careful cause they break easily) and put it out of the way. Some people remove the battery but I did'nt find that necessary.
Use a ratchet with the proper extension and you're set.

#3 opus

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Posted 13 May 2004 - 02:17 PM

My apologies, yes, it is a Legacy.

Good to hear someone survived changing plugs on one of these. Amazes me why they make things like this, where you have to dis-assemble the vehicle to pull plugs. Thanks for the tips!

#4 frag

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Posted 13 May 2004 - 02:34 PM

Opus, it looks a lot more difficult than it really is.
Doing what I listed takes about ten minutes max if the resevoir bolts dont give you too much trouble. After that you'll see that the plugs are easily reached with the proper extension.
In case my instructions were not clear enough, it's only the top part (cover) of the air filter box (the one you open to change the filter) that you have to unsnap and push aside. Unplugging a hose or two might make this easier but this will be intuitive and easy to do.
Good luck!

#5 opus

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Posted 13 May 2004 - 02:36 PM

Great! I am in Montana so there will be no issues about having bolt troubles.

Next time in town I will get plugs and have a go at it. Cant tell you how long I was looking for the distributor cap. :o)

#6 Chip Hedrick

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Posted 13 May 2004 - 06:07 PM

I changed the spark plugs on my '98 OBW two weeks ago. (I broke both of the bolts that hold the washer fluid resevoir, but they were the only casualties of the job.)

One thing that I found very helpful (this was recommended in the Haynes manual) was to use a piece of small diameter hose (I used transmission fluid hose) to thread the new plugs into their repsective holes.

Also, I had to buy a new feeler gauge because the two I had only went up to 0.040", whereas the Champion copper plugs I installed called for a 0.044" gap.

The only plug I didn't have enough room to tighten with a 1/2" torque wrench was the rear plug on the driver's side. I was able to tighten it with a standard socket wrench. I may have had better luck had I put the car up on jack stands and tightened it from underneath.

#7 Commuter

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Posted 13 May 2004 - 06:30 PM

Next time in town I will get plugs and have a go at it. Cant tell you how long I was looking for the distributor cap. :o)

:lol: Sounds like someone from my generation.

At least there are still spark plug wires to follow to find the plugs. Maybe you'd better sit down... but they've done away with those too on some engines. :)

Good luck. I've never done it myself, and don't plan to to be honest. Stick to NGK plugs. Platinums are recommended. And you won't have to change them again as soon as copper plugs. But up to you and what you like.

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#8 opus

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Posted 13 May 2004 - 09:11 PM

I use NGK in everything I own, from car, truck, snowmobiles, 4 wheelers, chain saws.

I must admit, there is more room under the hood of this '97 than there was in the '86....until last week :D

#9 NOMAD327

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Posted 14 May 2004 - 06:48 AM

I will copy over some info from previous posts I have made on the subject.

I used PFR5B-11 NGK which I found at advanced auto for $10, best price I found, and yes those are the original equipment plugs for the car. List on those plugs most places is $15 each and a lot of the internet sources wanted $12 or more with shipping extra. My kid who is on a budget bought Autolite APP3924 for about $4 apiece. They are double platinum and made in America. Very high quality appearance and seemed to match the NGK's for dimensions very well. The car runs like it should on them, so they may be OK to use. The plugs on this engine are real difficult to change, so I bought the NGK not wanting to have to redo the job if there were any problems

Once you remove the windshield washer bottle and battery (can probably just slide it forward on it’s tray a bit) on the left and the air inlet tube and mass air sensor and air cleaner box on the passenger side, access is fair doing a 2.5 in an outback. I would do the front plug first on each side, as they are slightly easier to do. What makes it the most hard is that the plugs are really far down inside the wells in the heads. The rear plugs on each side are harder because the frame rails are closer in the back. My problem was that an extension was needed, but there isn’t room to get one in with the socket attached. You have to slide the socket into the hole first, then slide in and assemble the extension, and finally attach the ratchet to the end of the extension. I immediately removed the sponge rubber plug protector from my socket, the reason being it will be extremely difficult to get the socket off the end of the plug and out of the hole if the rubber is gripping the spark plug. I didn’t want it on for plug removal either, because there is a lot of trial and error with your socket set as to what gives just the right length for getting the socket stack down into the hole. As I recall, what worked best for me was to use a plug socket in the rear, and then use a ratchet with a standard socket on it to turn the hex on top of the plug socket instead of using an extension. On the front plugs, a 3" extension worked pretty well with the regular spark plug socket and a ratchet. There was at least one plug which worked slightly better with a standard deepwell socket instead of the spark plug socket, but that was not a critical must have item! I would recommend having a small hand mirror on a stick or a ladies compact to be able to glance down into the well to see what’s happening. I’ve done a few of these cars, and on each one, at one time or another, the spark plug socket became slightly jammed on some aluminum protrusions of the head that were down deep in the well. The impression is that the threads are pulling rather than the socket is cocked and dragging. If you experience this, Use the mirror to reconnoiter. If in doubt, reverse direction, and the condition should go away if it’s not the threads. This usually happens when it’s just starting to go real good to scare the heck out of you.
Going back in with new spark plugs, make sure you check the gap first, then lube the threads with an anti-seize compound. Make sure there is a washer on the plug or you will wonder later on if it was in fact there. The big trick for installation, is to have a piece of rubber hose that’s about three or four inches long and a snug fit on the top of the spark plug. Stick it down over the top of the plug and use it to guide the plug into place. Twirl the hose between your fingers and you can probably get the new plug in half to three quarters of the way which ensures the threads are started straight. It's also much quicker and easier than a socket wrench as far as it will go. Putting all the stuff back on after the plugs are in, make sure the three quarter inch hose that connects to the bottom of the intake tract after the air flow sensor is reconnected, The car will not run without the hose connected, and sometimes it slips off unseen during disassembly, and you don’t even realize it needs reconnected.



#10 opus

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Posted 14 May 2004 - 09:36 AM

That certainly spells it out quite well for me....thanks for the detail!

#11 Chip Hedrick

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Posted 14 May 2004 - 11:39 AM

I am not impressed with platinum plugs. The last ones I had in my car were NGKs that the dealer installed. The dealer charged me $12.50 a plug.

The Subaru maintenance schedule indicates that platinum plugs are supposed to last 60k mi. I pulled those in my car after about 44,500 mi. Two were severely worn. All had gaps in excess of what the Haynes manual specifies (0.039"-0.043").

I replaced the NGK platinums with simple Champion copper plugs which cost $1.69 each. Immediately upon doing so, I gained back a lot of power (I'd guess at least 10 hp). Fuel mileage also has improved.

As I understand it, copper plugs are better electrical conductors, but do not last as long as platinum plugs.

IMO: If you are willing to change spark plugs every 12,000-15,000 mi go with copper (it may be a good idea to pull the plugs at this interval anyway, just because the condition of the spark plugs is a good indicator of what is going on inside the engine). If you simply want a longer interval between plug changes, go with platinum, but don't expect them to last 60k mi. I suspect 30k mi is more realistic.

#12 ron917

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Posted 14 May 2004 - 11:47 AM

At least there are still spark plug wires to follow to find the plugs. Maybe you'd better sit down... but they've done away with those too on some engines. :)
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And some engines have NO spark plugs at all, never mind the wires! :) If gasoline prices stay this high, I expect to see a lot more of those engines installed on cars in the US. (I'm talkin' about Diesel, of course.)

#13 Commuter

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Posted 14 May 2004 - 12:02 PM

(I'm talkin' about Diesel, of course.)

About a year ago, I was reading an article about direct fuel injection for gasoline engines. Granted, there are still spark plugs. But all else being equal, they said that an efficiency gain of 5-7% could be realized from this change alone.

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#14 ron917

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Posted 14 May 2004 - 04:05 PM

But all else being equal, they said that an efficiency gain of 5-7% could be realized from this change alone.

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5-7% still won't match a diesel. Check the VW Jetta, which is available with a gas or diesel engine, and allows an apples-to-apples comparison.

The 2.0L gas engine with automatic is spec'ed at 24 & 30 MPG. The 1.9L TDI diesel with automatic is spec'ed at 33 & 44 MPG. That's a 37-46% efficiency gain.

My brother owns a 2002 Jetta TDI automatic, and gets 42 MPG on his daily commute. When driving, you would be hard pressed to tell the difference between it and a gasoline model. It has tons of torque at low revs. The car is nothing like the '78 VW Diesel I owned - plenty of power, no smoke, no smell, very little noise. It's less noisy than my EJ25 on a cold morning :D.




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