Spark Plug Change on Twin Cam Engine

[uh_infinity]

My friend has a '96 Outback Wagon with the 2.5 twin cam engine and needs to have the plugs changed.   I found a post from Pooparu, but could not verify whether is '98 was a twin cam or not.  Is the procedure to build the tools one piece at a time onto the spark plug (spark plug socket, extension, rachet) and then remove the tools one piece at a time in reverse order?  Is there anything else needed, other than the socket, extension, and rachet?  Thanks.

[1 Lucky Texan]

96 might need new wires. OEM preferred. Aftermarket is dicey - maybe NGK or Denso specific for Subaru OK?

 

maybe some dielectric grease to coat the inside of the boots.

 

NGK or dealer supplied plugs SHOULD be pre-gapped. I'd check them to be sure though. If you get platinum or Iridium - be extremely careful as the iridium tip is easily damaged with gapping tools.

 

different length/size extensions. I've read of some folks using a length of tubing to help start plugs but, The 2 DOHC cars I swapped plugs on felt confident as for starting the plugs. Widely different opinions on use of ant-seize or oil on the plug threads - your call.

Edited September 10, 2013 by 1 Lucky Texan

[idosubaru]

yep that 96 is DOHC needs that "build a tool one piece at a time" method.

if his 98 was an EJ25 then it's also DOHC - all EJ25's from 1996-1998 are DOHC - and all 99 Legacy/Outback EJ25's are also DOHC EJ25's. 

 

 

removing valve covers helps in newer H6 engines, but unsure about EJ25's as i've only done them out of the vehicle so far.

[Rooster2]

It is a difficult job..........just so little room to work. It took me 2 nights to replace the 4 spark plugs. Do a search here.........much written in the archives on how to replace with less cussing and frustration. Still, it is a nasty job.

 

Suggest using anti-seize lube on the plug threads. It helps lubeing the threads for an easier thread in, and prevents future gauling.

[ferox]

When I helped my buddy change plugs on his '98 OB I removed all the plastic stuff to either side of the engine.  I think the two main items were the air filter box and wiper washer fluid reservoir..it's been a while.  They were really easy to remove and made access much easier.

[uh_infinity]

Thanks for all the advice.  I have tried the search, just haven't found anything yet.  Have tried search on spark plug, spark plug change, twin cam, cam spark change.  Just haven't found anything, except the one I mentioned previously.  Any suggestions on what else to try a search on, not looking for someone to do the search for me, just suggestions on what may work better.

[Rooster2]

When I helped my buddy change plugs on his '98 OB I removed all the plastic stuff to either side of the engine.  I think the two main items were the air filter box and wiper washer fluid reservoir..it's been a while.  They were really easy to remove and made access much easier.

All the above is true. I wrote on what it takes some time back, but can't find what I posted couple of years back. Some of the old posts may have been deleted over the years.

 

Basically, you will need a 3/8" drive and a couple different size extensions, a swivel, along with a sparkplug socket. I may have also used vice grips on an extension, when there was no room to use the drive handle. I think I also used long handled, long needle nose pliers, bent at an angle to reach inside the spark plug openings to remove fully loosened old plugs that have slipped off the sparkplug socket.

 

When installing new plugs, use a piece of rubber hose that can be slipped over the sparkplug,  then insert the plug into the hole and hand tighten the plug into the head grasping the rubber hose to rotate the sparkplug. Or, you can hand tighten a new plug by grasping and turning the extension attached to the sparkplug socket. Don't try to thread in a new plug using the drive handle and socket. If you triy that, it is too easy to cross thread the plug into the head, and therefore ruin the threads in the head. Then the new plug won't tighten down properly in the head, and you have just created a mess for yourself.

 

Be sure to use anti-seize on the sparkplug threads. It helps a lot to lube the plug threads upon insertion.

 

I have heard of some people loosening the engine mounts on the side of the motor they are working on, then jacking up that side of the motor to give better access to the sparkplug to work on. I have never tried this, but I am sure others here on the forum can comment on this approach.

 

Just take your time with this project. It takes patience to do this work with such minimal work space.

 

Good luck, let us know your results, or ask more questions............be glad to advise...................Rooster 2

[1 Lucky Texan]

looks like ther's a dozen videos on Youtube for Subaru plug changes,watching 4-5 of them might get you prepared pretty well for the adventure.

[uh_infinity]

Thanks for the advice Rooster2, all of it gives me an idea of how to get started and what to expect.  I looked it over a couple of days ago, and was suprised how little room there really is for it being a Subaru.

 

1 Lucky Texan:  I keep forgetting about youtube.  There have been some things I've looked for there, but keep forgetting to consider it as a resource.  Thanks for the reminder.

 

Again, thanks to all for the advice and thoughts.

[johnceggleston]

tips:

1/ remove the windshield washer reservoir and the air filert box to give your self more room to work.

2/ when removing the plugs, keep the rubber washer inside the socket so when the plug is unthreaded it will slide out with the socket.

3/ when installing the plugs DO NOT keep the rubber washer in the socket, that way the socket will come out with the extension.

if you leave the washer in the socket, the socket may stay on the plug. when you pull the extension out.

 

take your time.

 

#4 is the hardest, i do it last so i have practice before i get there.

 

good luck.

[Gloyale]

Spark plug sockets have a shoulder on them for a 3/4 socket.

 

So my method is

 

#1= slip in plug socket
 

#2= slip in a 3/4 deep well socket

 

#3= attach wobble

 

#4 attach extension and ratchet handle and remove plug.

 

Reinstall:

 

reverse order except as Gary said either remove the rubber washer from the plug socket.  Or use a bit of di electric grease to lube the waher and make sure it won't come out of the socket, but will come off the plug easily.

 

You don't want to have that rubber washer stuck on the plug down inside the spark plug well.

[1 Lucky Texan]

I used the method mentioned by John, 2 different sockets, one without rubber/magnet insert.

I also found these useful - especially on my H6;

Edited September 11, 2013 by 1 Lucky Texan

[Olnick]

So, what are they . . . other than pretty?!!

[1 Lucky Texan]

1/4, 3/8 and 1/2" ratcheting thumbwheels. Didn't use the the 1/2" but the set was cheap.

 

Not 'necessary' but it gives you one more option for spinning the plugs in/out. I think some newer-style ratchet handles have a knurled/serrated thumbwheel - but my old handles don't.