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How to change your sparkplugs

366K views 261 replies 97 participants last post by  Teawrecks 
#1 ·
Figured this might be helpful for somebody. First you'll need to properly gap your selected spark plugs- factory calls for .028-.031 gap, yours may vary depnding on model ie iridium or needs. Lots of info out there on choices of plugs- I won't go into any of it here.

You'll need to use some kind of gapping device and you'll want an accurate gap. Here's the tool I use:
 
#55 ·
Loose plugs?

Thanks for the instructions, it wasn't that bad. One question, if I didn't tighten the plugs enough, what symptoms should I look for? The car seems to run only slightly rough, but much improved with the new plugs/ air cleaner. Since I couldn't get a torque wrench in there, I was more worried about over-tightening. Yes, I'm green. But I'm learning a lot from you guys and trying simple stuff like this first. So, thanks again.
 
#56 ·
Loose plugs?

Thanks for the instructions, it wasn't that bad. One question, if I didn't tighten the plugs enough, what symptoms should I look for? The car seems to run only slightly rough, but much improved with the new plugs/ air cleaner. Since I couldn't get a torque wrench in there, I was more worried about over-tightening. Yes, I'm green. But I'm learning a lot from you guys and trying simple stuff like this first. So, thanks again.
 
#59 ·
Big Sky WRX said:
The manual shows 60,000 miles on the oe platinum ones- I like to check at 15,000 and if OK replace at 30,000.

Thanks for the quick reply.

Since I am about to purchase a 04 WRX w/ 35K miles. What all do I need to make sure or see if the dealer has done as for all-a-round maintance work?

So far I am going to ask if these were done:

*PVC value been replaced.
*Fuel filter replaced.
*TB and air element been clean or replaced.


Any others w/ these kind of miles?

:cool: Thanks again
 
#61 ·
Yea.. I just downloaded the file and just printed it. Looking over it.

Looks like 30K service is:

oiil change, brake fluid, fuel filter, radiator, air filter and pvc (which does not show in it).

The spark plugs as you mention is 60K replacement.

Big Sky WRX said:
Try this thread- it has a link for the scheduled maintainence- the 30,000 one should have been done.

http://www.clubwrx.net/forums/showthread.php?t=10988
 
#63 ·
I did the plug change yesterday. I want to re-emphasize a note that Big Sky made. Use a locking extension on the plug socket. Mine pulled out of the socket, so I had to get in there with some little pliers and pull the socket off the hard way.

It didn't add a whole lot of time, but it sure aggravated me. I'm off to Sears this morning to buy some better extensions. Never again!
 
#64 ·
thanks big sky, this thread helped a ton! i would have made a boat load of mistakes.

couple of things I noticed with my plug change:

on my 05 wrx, the battery did not need to be removed. maybe the 04 you have is slightly laid out diff but i got in there ok with the battery in. it was a little tight buy i managed.

some

i found a trick to get the socket off the plug you just installed: the first plug i put on the socket got stuck, had to use needlenose pliers to work it out. on the rest, i decided to throw a little spit on the insulator... as a lube... it helps the socket slide off w/o getting stuck in there. hehe, if you've never used spit as a lube before, youre lyin. ;)

careful with the ratchets and sockets on the passenger side. when they drop they are hard to get, you need a set of needlenose to fish them off the skid plate, that's a real pita

someone asked which side the black and white plugs go on. for me it "black in back", white by the lights (thats the stupid rhyme i used to remember which wire went on which plug, but it worked)

last i would say take your time... my first time was about 1:45 or so, but there
some things you don't want to forget to install if you rush and fock up. next time it'll take me under an hour. thanks man.
 
#66 ·
Big Sky WRX said:
Glad it's been helpful guys :)

I'm missing the black and white plug thing though?
my bad... i think that someone on another thread (sorry I mixed that up, it was getting late, must've thought it was this thread) placed the connectors on the wrong coil pack. which made the car run a wee bit off. so i was just mentioning it for anyone else who might make the same mistake: the black connector (and your photos clearly display this) goes to the coil pack on the back (towards the firewall). white connector goes on the front coil pack by the lights. sorry to be a bit confusing above.
 
#68 ·
I have a few questions. First what size flex sparkplugs socket do you use. I know most everything is metric ,but I couldn't find a metric plug socket. Is it just a 5/8" plug socket? Second question is how do I know if I have platium plugs or not. I haven't changed my plugs yet and my car has about 28,500 miles. The service manual says to change them at 30,000 and I have heard that platiums last about 60,000. I have a turbo back exhaust and a MBC plus a CAI. In the future I plan on adding a uppipe and a UTEC. If I change the plugs now will I have to re-gap them later after the mods? Should I start with about .028 gap for the mods I have? Thanks for this tread it has already helped me alot. :)
 
#71 ·
Big Sky WRX said:
5/8 " is the one you need :)

The platinum plugs call for 60,000 change in the owners manual, I'd at least look at them at 30,000 (and replace while your at it).

The oe plugs are NGK PFR 6G
buy them anywhere but subaru if possible. 55 bux just for the set. and the STi plugs were 13.55 each or something close to that and i think they were cheaper through advance.
 
#73 ·
To those of you who like the flex sockets...
What should I buy,
A set of flex sockets?
A flex head ratchet?
I have both 3/8 and 1/4 drive ratchets, being that the flex sockets are for getting into tight spots, would it make more sense to get the 1/4" drive sockets (my 1/4" drive ratchet is about 7" long), or would I be needing more torque?
Thanks,
Brian
 
#74 ·
SubeN'Siren said:
To those of you who like the flex sockets...
What should I buy,
A set of flex sockets?
A flex head ratchet?
I have both 3/8 and 1/4 drive ratchets, being that the flex sockets are for getting into tight spots, would it make more sense to get the 1/4" drive sockets (my 1/4" drive ratchet is about 7" long), or would I be needing more torque?
Thanks,
Brian
well, the back driverside is so hard to get to you need flex heads for everything, and also for when your taking the plugs out because the motor sits a bit lower than the frame and you have to angle it in to get them out right. thier a worthy investment, trust me. and buy craftsman because if you try the back like me, you'll break the 12mm flex.
 
#75 ·
turbo_bxr said:
well, the back driverside is so hard to get to you need flex heads for everything, and also for when your taking the plugs out because the motor sits a bit lower than the frame and you have to angle it in to get them out right. thier a worthy investment, trust me. and buy craftsman because if you try the back like me, you'll break the 12mm flex.
btw i didnt use or buy a flex head rachet. thier annoying as hell anyways.
 
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