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How do you remove the spark plugs from a Legacy GT


Qball
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Dear All

I need some help - new to the Scooby scene and I have a small problem. I have done a complete service on the Subaru Legacy GT E-Tune Rev D that I bought in July this year. Only thing is I cannot see how you get the spark plugs out. According to the Subaru work shop manual you should remove the washer bottle and the air intake, undo the bolts holding in the coil packs over each spark plug and undo the spark plug. Big snag here is that there does not seam to be enough room to remove a) the coil pack retaining bolt b) the coil pack or c) the spark plug with conventional tools. It's because there is a bit of the chassis that is so close to engine on both sides. Do you need to lift the engine in order to get the clearance that you need? Help please anyone!!

 

Also does anyone know what the normal oil consumption should be? I have been told anything up to 250-350 miles to the pint. Is this correct?

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Tools you will need: 


10mm socket or ratchet - to remove intake and Battery

12mm socket to remove coil pack bolts.

1/4 drive socket wrench with 12mm socket for the two rear coil packs (It's tight).

5/8" spark plug socket 

2", 3" and 12" extension for 3/8 drive wrench - For removing the spark plugs and coil pack bolts. 

A knuckle extension. 

Anti seize - I use this on the spark plug threads

Dielectric grease - I put a dab on the top of the spark plug where the coil packs wire touches the plug


Do the spark plug change when the motor is cold so you don't risk striping something or burn the living daylights out of yourself. 


First start by removing the airbox and all of it's plumbing up to the inlet hose. First start by undoing the hose clamp that connects the airbox rubber hose to the inlet with a screw driver. The unsnap the air box clamshell clips and pull the back half of the airbox out of the engine bay. Now with a long extension remove the two 10mm bolts that hold the airbox to the fender. Don't forget the 1 10mm bolt inside the airbox as well. 

Once the airbox is out go ahead and remove the Battery tie down with the 10mm socket. Once that is out of the way remove the batt cables. Remember to undo the negative first and then the positive Battery cable so you don't risk getting a zap. (Installing will be positive and then negative). 

Getting the airbox and Battery out will make for a lot more room as things are tight as is. Doing the WRX/STI some will take out the window washer bottle, but that is not needed for the LGT.
 
 
 
Getting the coil pack off of the spark plug isn't all that hard for the two on each side in the front of the motor. The gold bolts you see are the only things that hold the coil pack onto the motor. Using a 12mm socket and knuckle along with a 3 inch extension remove the bolts. The fronts are simple and you have plenty of room. The back coil packs it's tight. This is where the 1/4 drive comes into play. The engine bay tapers to the rear so it will take some patience for the rears. I found that if I got the bolt loose enough I could take the ratchet off and keep the 12mm socket on the bolt and loosen it by hand. Don't worry about the bolts coming out of the packs, they don't. The rear passenger side coil pack has a bracket attached to it for the EGT wires that run to the Up pipe  Once the bolt on that pack is loose the bracket will fall to the side. It's ok and is easily put back when the coil pack goes back on. To distinguish the front pack from the rear pack the wire harness that runs to each has a white and black adapter . The pack with the white adapters are the front and the rear is the black.
 
The front coil is a piece of cake and is just as easy as the passenger side front. However, the driver side rear is a headache. The space is tight and the problem is not getting the 12mm bolts off, which is the same as the passenger side. The rear coil pack does not have a lot of slack to it in terms of the wires running to it. On top of that, it is extremely close to the fender wall and takes some work to get out . The previous three coil packs you are able to take out and draw them up. However, the drivers side rear you have to place below the cylinder because it is too tight to pull it up.

 

Once you have the coil packs out of the way you are ready to remove the spark plugs. What I found to be the easiest for all four cylinders is to slide the 5/8 inch spark plug socket onto the spark plug first, and then the knuckle extention, the 12in extension and then the 3/8 ratchet. The spark plugs are deep so your gonna be thinking these things are never gonna get out. Be patient with the rears because you are at a very odd angle. The closer you can get to perpendicular with the cylinder the better you will be. Here is a side by side of the old and the new. 

Before you start to install the new plugs when all the old ones are out, check the gaps between the two. I know the spark plugs come pregapped, but you don't wanna find out after you have them in that the gap is too large and your misfiring. Be careful when you check the gap to not damage the electrode (it is very delicate).
 
 
Before you install the new plugs, go ahead and put some anti-seize on the threads (you'll appreciate it if you ever need to pull them out again). You can use dielectric grease on the top of the plug that connects to the coil pack if you choose. Once the plug is prepared place it in the 5/8 spark plug socket. I have read that some take the cushion out of the socket, I don't find this to be a great idea because for the rears you are working with weird angles and risk cracking the plug should the socket slip off the plug. Connect the socket to a 2" extension as the cylinder is deep. Your going to wanna install the plugs by hand first as to not cross-thread the plug into the head. Again, doing this by hand for the rears takes patience. Once you plug threads into the head attach the knuckle extension and then the 3" extension followed by the 3/8 ratchet. Go ahead and tighten the plugs in. 

Once all the plugs are in you can put the coil packs back on. Remember, the coil pack with the white harness is the front and the black the rear. Another thing to keep in mind when you install the packs back onto the plugs; you are not going to get the distinct snap that you would with a set of wires. With each pack you put on go ahead and slide the 12mm socket onto the gold bolt and hand tighten them first and then pop on the knuckle extension and 12in extension with 3/8 ratchet to tighten them down fully. Remember that the passenger side rear pack holds the EGT bracket, so before you tighten it down too far slide the bracket back onto the bolt and then tighten it down. 

Once all the packs are on reinstall the air box and your battery. Go ahead and start her up! Don't forget to reset the clock, radio stations.  

 
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Only just seen this post... Yes it's a pain in the !Removed! job and you need to make sure you have the right tools for the job otherwise you won't get access.

Remember the cylinder heads are aluminium so be careful not to over tighten anything as stripping a thread will cause a world of pain.

Also, if it's a Rev D then it will be a GT-B E-tune 2 and you should have smaller turbos for quicker spooling.

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Hi Adam

You are right with the Rev. It is a Revision D - it came into the country last November registered on a Y Plate.Looks as though I am going to go through a whole heap of pain to do the sparkies but its got to be done. Wish me luck. Qball

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Hi Gambit

Yes you are right - I became a member before collecting the car in fact in July. I have been enjoying the car since then, its my only mode of transport and regularly takes me up to places like Durham giving me good mpg around 33 - 35, which for monster like this is pretty good going. Used to be a SAAB man - set up the SAAB owners club for Kent some years back. Have had a few hairy SAABs as well, my last was a Works built drop head CS 9000 Carlsson with around 300hp. So many strange bits on it - it became difficult to source them! SAAB Trollhatton HQ and me were best buddies as a result!! Thanks to all for the hearty welcome - have a feeling that my relationship with Subaru's will be long and very enjoyable - should have bought one years ago!!

 

Qball

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Phew alzheimer's not creeping in yet then :D 

And good luck with the change, I've never done anything to any car that has made me say " F$% it. Thats it!  I'm going to pay some "£^&* to change F%£!ing things next time" But still end up doing it the next time  :lol:

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I remember the first time I did sparks on a GT-B... A friend and I both needed them doing so we parked side by side and spent what seems like all day trying things on one car and then copying on the other. Got a huge sense of achievement at the end of the day and a free dinner from my friend.

Since then I have bought the correct tools and done the job loads of times. It's so much easier the second, third fourth time around and now I find myself wondering what all the fuss was about.

You'll be fine once you break your cherry!

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Excellent write up Gambit.

First time you do it it will take ages. After that, each time you do it, it will get faster. In the end, it's a 20-30 minute job....... Once you've grown the double joints you need in your fingers. ;)

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  • 1 month later...

Hi Gambit 

 

Since opening this thread up in December last year I have been trying to get a chance to do the job of replacing the spark plugs. However, a combination of of work commitments, the weather which has been less than friendly and Christmas has made it impossible to get to. Not any more. This weekend just gone  I managed to do the job. From start to finish it took me 3 hours to complete. I have to say of all the four spark plugs the one that gave most trouble was the RH rear. I have invested in some spark plug sockets that have integral UJ's - this has given me the articulation that I needed. Also I found that by removing the windscreen bottle, Battery and Battery tray from the RH side as well as the air intake and air scoop on the LH side, access to the plugs was much easier.

 

Qball

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Nice job mate glad to hear it. I told you it's a pain in the !Removed! though ;) I hate doing them and the back one is by far the worst I've even known people to leave it and not change it I do wonder if that's why a lot of people get misfires on Cylinder 4 codes. 

But least it's done now and you know what to expect on the next attempt.... More swearing ;) 

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Funny thing is I found that if you disconnect the coil pack from the wiring loom on the RH rear, you can then pull the pack out slightly turn it through 90 degrees and then you can take advantage of the flex in the coil pack plug shroud to feed the coil pack out of the way of the engine going towards the bulk head of the engine bay. I think the key is to take you time, then its a piece of the proverbial wee - wee!!

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