How to change spark plugs, wires, etc?

xgabriel

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2008 Mazda5 GT
I'm having some problems with my 2002 Protege5 (see this thread: http://www.msprotege.com/forum/showthread.php?t=123701316) and I've decided my next move is to give the car a tune up. I bought the car with just under 50k miles on it, and it now has 88.5K miles. I have no idea if the local dealer I bought it from changed the plugs and wires before I bought it, but since it has been about 40k miles since I bought it anyway I figure it is a good idea to do it now. However, I've never done this kind of work on my car. I change the oil myself, but that is about the extent that I have gone. This car is just a daily driver, and I am no mechanic. Can somebody give me a "how-to" on this subject? I've seen the sticky about which plugs and wires to get. Do the plugs come pre-gapped? Honestly, I'm not even sure what "gapping" means, so if you could explain it to me I'd appreciate it. Sorry for the noob thread, but I could really use your help.
 
Go buy OEM wires and plugs.
Take off old, remember how they came off.
Install new the reverse of how the old came out.
Super easy.

The plugs come pregapped. The gap is the space between the electrode and the prong.

You should check that they are all the same but I haven't had much trouble with OEM parts.
 
Thank you very much Nomad! Any more specific tips that anyone would like to share would be greatly appreciated.
 
Make sure you have an extension for your ratcheting wrench, a 5/8 spark plug socket, and a 10mm socket to remove the coils.
 
Do we all have the same engine?

If so, my advice is the take a pic of the coils and wires. It isn't too difficult to figure out how they go, but you can never be too careful. I just checked O'reilly Auto Parts and the 2 wire set goes for $23.99 and each Coil is $13.49. So you'll spend about $50 changing everything. Unless you just want to change out the 2 wires.

Always make sure to hand tighten the plugs first, then use a socket wrench or torque wrench to finish the job to the proper torque as mentioned above.

Don't forget to put some Anti-sieze on the threads of the plugs and I like to put the silicone lube on the boots to keep them from sticking also. On both coil and plug ends.

As far as I know the spark plugs don't come pregapped. And they sell a gap tool for $0.99. It's about the size of a 50 piece with a bunch of little numbers on them. You can slide your plug(on the thread end) on the edge of that gap tool and when it stops, that's how much the plug is gapped. It should be at or near 0.44.

Then you just snap everything into place and bolt down your coils and you're good to go! I've heard that unplugging your battery for a few minutes helps also so your computer can reset for the new parts is a good idea. But to each his own. :) Good luck!
 
sorry for a quick thread jack, I have a whole set of metric sockets range from 8-19mm, do I still need to get the 5/8 socket? (in inch?)
And...what's gonna happen if I don't put anti-seize? I mean, I don't think I will have problem taking them off since I have a breaker bar...


Josh
 
Its a 5/8 socket, but a special one. I'd just get it if you can find the 99 one because it has a little rubber gasket inside that wraps around the plug to take it out. If you use a regular socket it'll be a b*tch to get the plug out.

Using a breaker bar on spark plugs is scarey! Just take the safe route and use anti-seize. :)
 
you need a 5/8 spark plug socket...its much easier to use since it has a rubber grommet (or whatever) inside that holds the plug so you can pull it out...

And anti sieze is not needed so plus are "easy to get out" cuz if you need a breaker bar to remove them that could equal bad news....you want the anti sieze on there for exatly what it says, so they wont seize in there. cuz if you try to break it loose and break off the top of the plug, you're boned....
sorry for a quick thread jack, I have a whole set of metric sockets range from 8-19mm, do I still need to get the 5/8 socket? (in inch?)
And...what's gonna happen if I don't put anti-seize? I mean, I don't think I will have problem taking them off since I have a breaker bar...


Josh
 
Oh ok, that makes sense. I never change a spark plug. :D
Is there different types of anti-seize? or I can just go ask at the counter and get whatever they give to me.

Josh
 
you need a 5/8 spark plug socket...its much easier to use since it has a rubber grommet (or whatever) inside that holds the plug so you can pull it out...

Good call on that. But if your socket doesn't have the rubber inside, you can also use the spark plug wire to fish it out after unscrewing.
 
Be safe, use the rubber.

The anti-seize is also to protect the aluminum head from corrosion when two dissimilar metals contact each other. If you put them in dry then over time the metals can react and eat away and weaken the spark plug holes.

Also, when you are at the .99 store pick up a 10" extension. You'll need it to reach down into the spark plug holes. Make sure the plugs have the small crush washer on them. You don't "need" a torque wrench as long as you don;t go crazy on them. Twist the extension by finger to set the spark plugs into the threads, then ratchet them down with light force till you feel the plug stop at the crush washer. This washer is meant to deform and seal when squeezed. It is approximately 1/2 turn more to completely crush and seat the plug after it stops at the washer. You'll feel the pressure go from light on the threads, to heavy as you crush the washer the last 1/2 turn and then extremely tight when you have fully compressed the washer. Don't twist any further once you feel the washer compressed.
 
Thanks a lot Nomad! Now I'm confident to do it lol!
hopefully it will be sunny this weekend and I can spend a little time on my P5.

Josh
 
I just switched over to the long reach plugs, and I was too scared to do even 14 ft/lbs. I just made sure they were tight. :) I didn't want to strip anything, so beware and be careful! :)
 

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