How do you change the spark plugs on a 2001 Subaru Outback LL Bean with the 30 H6 engine?

Answer 1

I've change plugs in quite a few different Subaru 4 cylinder motors (H4) this is the first 6 cylinder (H6) I've done. While not super hard it is pretty tedious and at times frustrating. There isn't a lot of room to work so having the right tools is a must. Small hands helps too and a lot of patience. This was done on an 2002 LL Bean Outback. I suspect the VDC will be the same.

Tools you'll need:

10mm socket or ratchet - to remove motor cover, front part of intake and wire stay rail on drivers side of motor (LHD)

12mm socket and long extension - to remove airbox bolts, socket removes coil pack bolts too.

12mm open end - sometimes getting at the coil pack requires an open end due to tight quarters.

Flat blade screwdriver - to remove hose clamps that fasten on intake hose to air box. It's also used to separate the extension from the socket.

Flex head ratchet - This helps a lot getting a better swing instead of a lot of little clicks removing the spark plugs.

12mm socket and ratchet 1/4" drive - The back plugs by the fire wall have very little room to remove the coil pack. I needed a small or rather thin headed ratchet to fit in there. I had to use a 1/4" drive. Try with your 3/8" drive it may be narrow enough mine wasn't

5/8" spark plug socket - to remove spark plugs, note remove the rubber cushion insert inside the socket. If you don't you will have a heck of a time getting the socket off the spark plug after you install it. It's in there deep an it's tough to grab.

3" extension for socket - For removing the spark plugs this is a must any bigger or smaller will not work

Retrieval Magnet - I have one on the end of a telescopic want and used it many times during this procedure. From getting tools I dropped under the car to getting the spark plug out of the hole.

Spark plug gap measuring tool - a flat blade is best for new plugs not the round type - To verify spark plug gap of 1.0 - 1.1mm or 0.039 - 0.043 inch. The plugs come pre-gapped but it does not hurt to double check them.

Drop light - to see better of course

Optional:

Anti seize - I use this on the spark plug threads

Dilectric 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 on a stone cold, sitting overnight, motor. With a warm or hot motor you risk stripping something and getting a nasty burn too.

First start by using the handy dandy but little known feature all Subaru's posses. Open the hood all the way up.

First start by removing the front part of the intake I like to call the Platypus. It's held in place by 2 - 10mm bolts. After you remove them the duct will just unhook from the back. Then remove the airbox rubber hose by undoing a hose clamp on the top of the airbox with a screwdriver. Take the top of the airbox off by undoing the two clamshell clips and removing it. Now with a long extension remove the two 12mm bolts holding the bottom half of the airbox to the fender. A long extension or a few together are needed to reach the bolts. For the bolt towards the firewall, the magnet helps get the bolt out after it is loose. Remove the whole bottom half by finagling it out of the fender area.

Next on the other side remove the washer bottle (2 - 10mm bolts), hoses and pump harness. When you unplug the washer hoses fluid will come rushing out. So be prepared to turn it on it's side to prevent losing all the fluid. Also removed the battery.

To remove the battery (wear gloves and goggles when dealing with a battery to be safe) always undo the negative first when removing the battery, then the positive. This reduces the risk of a tool hitting something and arching. When re-installing it do the opposite, positive terminal then the negative.

Do one plug at a time, removing the coil pack and then remove and replace the plug and coil pack.

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. It's close but you can get a 12mm socket on them. They aren't in there too tight and the bolt will stay in the coil pack and not drop out which is nice. The trick is to get the coil pack out of the way enough to get to the spark plug. I pushed the coil pack down below the spark plug opening for all but the last one I will get to later. For the rear coil pack it's a little trickier. The motor bay seems to taper back and gets closer towards the firewall. My flex head socket was too large and I had to use a 1/4" drive ratchet setup with the 12mm socket to get that coil pack off. Same thing on both rear coil packs. It can be tedious at times because you can only get a few clicks of the ratchet to move the bolt.

Once you have the coil pack out and moved out of the way now you need to get the plug out. As I mentioned earlier remove the inner cushion from the spark plut socket if there is one in there. To get the plug out, I slipped in the Spark Plug socket first, then the 3" extension. This can be tricky because you need to feel that you are getting the extension in the socket end, you can't really see what you are doing. And then put the flex ratchet on the extension. When the spark plug is loose (or you think it is) you will now have to remove the ratchet from the end of the extension. It sounds easy but there is little room pull it off. So I used a long flat blade screw driver to first separate the ratchet from the extension then the extension from the socket. The spark plug will most likely be sitting in the hole where you can't see it. You can use your magnet to get it or possibly reach it with your fingers.

Now you are ready to install the new plug. Be sure you compare the old and new plug to be sure you got the right ones, and double check the gap. I like to put never seize on the threads and some dialectic grease on the top. That's up to you. Putting the plug in is similar to getting the tools in to remove it. Now you will have the plug in the socket. Slide the socket/plug in the spark plug hole. Put the extension on the socket and (this is very important) start the plug in the threads by hand, gently turning the extension to seat the plug all the way to the crush washer gasket. You do not want to cross thread the plug that would be a very bad thing. The good news is Subaru has seemed to make it easy to get the plug started properly.

The rear plug on the drivers side (LHD) was a bit of a bugger and necessitated the invention of new and different swear words. To give more room moving the coil pack around to get a the plug I had to remove a metal guard/rail that held the harness to the coil pack in place. It's held in place with two 10mm bolts and at one end is a plug you need to undo from the harness to move it aside. Here I used the 1/4" drive ratchet to get to the coil packs 12mm bolt too, just like the other sides back plug.

Well that's about the size of it, now replace all the bits you removed to get at the plugs and you are done. Well other than resetting your radio stations and clocks time