Was going to change out spark plugs on my 02 Forester, and noticed that quite a few people on here have had problems stripping out the head and/or messing up threads. I've replaced plugs many times on my honda...in fact, my honda uses the exact same NGK spark plug.....but dont want to mess with fouling my head if for some reason Sub's are notorious for stripping out. Is this true or am I just seeing the limited few with problems??

 

Obviously I'm going to use a torque wrench and anti seize.

The difficult access angle is what I think leads to trouble. People are used to just dropping the plug down the hole and cranking. You have to be very careful to get the threads started correctly, then it becomes as simple and easy as any other car.

To me, and I think most will also agree, the most important thing to keeping the theads intact is to make sure the replacement plug is started in the threads correctly. This usually means starting the threads by hand and feeling for the correct starting position. Once the plug is in place it is then torqued to the proper pressure. I usually just go by feel on that and have never had a problem.

as long as you feel confident go ahead and do them.....granted they are pretty difficult to get to.....just use an extra long extension dont overtighten them.........how many miles are on your subi. and how long have those plugs been in there?

Dang! Beat out by Gloyale again .

 

One trick that may help get the plug started in hard to reach situations is using an old plug wire mounted on the plug and us it to spin the plug in place.

If you use the proper spark plug socket and extension, start threading the plug by lightly holding the extension with your fingers(without the ratchet). I've always used that method and never had any problems.

i don't think it's all *that* common, there was one recent thread in the past few days. i doubt you'd find more than a handful of threads if you did a search.

 

don't know if someone mentioned it already, but don't do it when the engine is hot.

Was going to change out spark plugs on my 02 Forester, and noticed that quite a few people on here have had problems

 

Obviously I'm going to use a torque wrench and anti seize.

 

I always use some 40 cm of plastic garden hose , which fits narrow on the

ceramic part of the plug.

Only the first 2 turns with a key , as well as the last 2.....

Thanks for the replies. The forester is at 90,000 mi. Inherited it from the inlaws and it looks like these plugs have about 30,000 mi on them. Not sure if platinums were used as the dealer changed them last time. Will probably throw OEM wires on it too.

 

PS, I am not a fan of plug changes in boxer style engines. Remove the air box, battery, and washer resivoir???? what a PITA!!

PS, I am not a fan of plug changes in boxer style engines. Remove the air box, battery, and washer resivoir???? what a PITA!!

It's only that hard on the engines that have 90deg plugs, not the ones with the 45deg plugs like the SOHC models.

"Remove the air box, battery, and washer resivoir???? what a PITA!!"

 

Interesting, I had no trouble on my 2.2. I didn't think the 2.5 would be that much wider.

 

If you going to use platiums and leave them in a long time. Please, please, please... use anti- seize.

 

I've had several used cars over where previous owners left plugs in too long without anti-seize.

 

Pet peeve.... drives me nuts.

"Remove the air box, battery, and washer resivoir???? what a PITA!!"

 

Interesting, I had no trouble on my 2.2. I didn't think the 2.5 would be that much wider.

depends which of the EJ motors you have, some EJ22's (later 1999+) are a PITA. the ones at 90 degrees are a pain. the 45 degree ones are simple.

depends which of the EJ motors you have, some EJ22's (later 1999+) are a PITA. the ones at 90 degrees are a pain. the 45 degree ones are simple.

 

Mine's a 91 Legacy

Mine's a 91 Legacy

Easy. You don't have to remove anything. Just get creative with the plug back near the washer fluid and you're fine.

2 hex head screws and another person to hold the washer bottle out of the way. Don't even need to disconnect it.

 

Does make the access a LOT easier (was doing valve cover at the same time, though)

2 hex head screws and another person to hold the washer bottle out of the way. Don't even need to disconnect it.

 

Does make the access a LOT easier (was doing valve cover at the same time, though)

 

+ 1 on this one.

But go easy on those hex head screws. It's very easy to break them if they are rusted. Been there...

Thanks for the replies. The forester is at 90,000 mi. Inherited it from the inlaws and it looks like these plugs have about 30,000 mi on them. Not sure if platinums were used as the dealer changed them last time. Will probably throw OEM wires on it too.

 

PS, I am not a fan of plug changes in boxer style engines. Remove the air box, battery, and washer resivoir???? what a PITA!!

Washer tank 2 bolts and 1 or 2 elect. connecter OH MY! Air Box 4 or is it s 6 bolts? SAVE ME from this ordeal! The battery I leave in. Try plugs in a FWD V6 Ford or GM sometime and get back to me.

Washer tank 2 bolts and 1 or 2 elect. connecter OH MY! Air Box 4 or is it s 6 bolts? SAVE ME from this ordeal! The battery I leave in. Try plugs in a FWD V6 Ford or GM sometime and get back to me.

Yeah, on GM you have to basically rotate the entire engine forward in order to get at the back plugs.

Yeah, on GM you have to basically rotate the entire engine forward in order to get at the back plugs.

 

On that note, to get at plugs on DOHC motors, you can unbolt one engine mount at a time(and the dogbone) and jack that side of the engine upward to clear the framerails.

Do you guys have any suggestions for removing the plug wires from the head? Two are really stuck in there. I've just about done everything but torch the F'ers out of there. Twisted and twisted while pulling, no go. I started tearing the rubber boot im pulling that hard.

As mentioned by others, care needs to be taken to avoid stripping out the threads on an aluminum head motor. Unscrew a plug, and rescrew in a new plug on a straight line, with no torque applied at a side angle. Hand tighen only when first threading a new plug into the head. I use antisieze on the threads. It helps to lube the threads for easier threading into head, and also easier removal upon replacement in the years ahead.

antisieze on the threads

 

I've always used simple engine oil.

antisieze on the threads

 

I've always used simple engine oil.

 

What do you do for stuck plug wires? The subaru dealer who changed the plugs last obviously didn't use dielectric goop so the wires are seized to the plugs. Looks like I may have to cut them out.

 

At the wires I did get out, I found at least a teaspoon worth of engine oil around the outer portion of the spark plug tube. Is that somewhat acceptable?

Do you guys have any suggestions for removing the plug wires from the head? Two are really stuck in there. I've just about done everything but torch the F'ers out of there. Twisted and twisted while pulling, no go. I started tearing the rubber boot im pulling that hard.

 

Use boot protectant when re-installing to prevent this from happening again.

At the wires I did get out, I found at least a teaspoon worth of engine oil around the outer portion of the spark plug tube. Is that somewhat acceptable?

 

Some slight weepage might be ok, but a teaspoon is no good. There are gaskets under the valve covers around the spark plug wells which need to be replaced. You'll also want to replace the grommets around the valve cover bolts and the valve cover gasket itself at the same time.

 

Nathan