Changing my Spark Plugs - any tips?
 

Seeing as how my P5 has over 27,000 miles, the recommended plug change is every 30,000, and my lady's Jeep needs plugs, I plan on changing my plugs tomorrow along with hers - it'll an "automotive maintenance" kind of day ;).

I already got the plugs - OEM NGK's - I'm not looking to change anything or run colder/hotter plugs - OEM is fine with me.

I just want to know if there is anything I should look out for - I was looking at the engine today (forgot to check for that heat shield bolt that just hates to stay put - I'll look tomorrow - anyone know the exact size of the bolt in case I need to replace it?) - I realize I will have to un-bolt the coil packs to get at the plugs - anything else I should know or be careful of?

I've got my plugs and anti-seize compound ready to go, and I've done plugs on aluminum heads before, so I know not to over-tighten them.

Let me know if here are any surprises I should be wary of - I'll check back tomorrow morning for advice before heading out to work on it.

Thanks!

~HH

Pull the wires off the plugs using the top of the rubber boot and not the wire. Other than that, it's a piece of cake. They are 5/8" plugs by the way so make sure you use a 5/8" plug socket instead of a 13/16". Also, make sure that there is a foam or rubber insert in the socket so the plugs come out when you lift up. They are quite a ways down in the head.

another thing....take a peek in the hole before you remove the plug....make sure there isn't any dirt in there...it will fall into the motor if there is ..... wouldn't hurt to just use some compressed air to clean the hole out or ensure it is before pulling the plug out.

Thanks for the tips, guys - I just finished up, and damn, was it ever easy. No surprises - just the way I like it :D

If only the lady's Jeep was so easy - plug access is simple, but the damn boots were so tight, I tore the hell out of two of them getting them off - so she got a new set of plug wires, too. ;)

You don't have to tell me - I remember what a hassle it was to swap plugs and wires on my 305 V8 Camaro.

But then again, certain things are easier - like alternators, belts, etc. The plugs are easy on the Pro - but so much else is put together with such tight clearances, I don't know if I'd be able to get at them - it's a tight little engine bay.

Actually, I've worked on a ton of cars and the access on the 3rd gens is pretty damned good. There is a lot more space between the accessory drive and the shock tower than a Probe also. The only thing hard to get at is the pivot bolt for the alternator. Once you learn that it can be reached easily from underneath, you're golden. So far I've had a lot of things on and off my engine including the cam drive twice and the whole front half of the exhaust system twice. I'm fairly happy with how easy it is to work on considering all the other cars I've worked on. At least you can see and get to just about everything unlike GM, Ford, Chrysler or some Toyotas.

Another good thing to do is "anti sieze" on the threads.

Hehe - well, more han a "good" thing - it's a NECESSARY thing when installing plugs into an aluminum head.

Also - FYI for everyone (something I didn't know) - it's always recommended to change plugs in an aluminum head when the engine is cold - not just to save your hands, but the aluminum is a LOT softer in a hot engine, and you stand a much greater chance of stripping or galling the threads on a hot motor than a cold one, even if you do everything 100% correctly, use a torque wrench, etc, etc. Buy the plugs the day before (or early in the day), and install them the next day before driving (or later the same day when the engine is fully cooled).

Maybe this is common knowledge to many, but it was news to me - luckily I found the info while searching for install tips, and followed the advice.

~HH

I think a lot of people probably knew that but that is a very good tip to remember for the more inexperienced type peoples.

Anyway it is almost always better to work on a cold engine (unless some kind of diagnostic work requires it be warm). Something about burned knuckles. Plus the whole metal thing there. Good idea to have a torque wrench when you do something like this (especially if your an anal bastard about it). Used to I changed the wires too but I think it might be a little too expensive on our Pro's to be worth it.

OK - I'm at 27k miles, and am wondering about chaning my plugs at 30k. Is it really worth it?

A friend - whose opinion I respect - said modern engines should be good for 90k easily.

Anyway, a couple of people have mentioned torque wrenches, but no torque spec.

Does anyone know the recommended torque spec for our plugs??

The manual recomends it - is really NOT worth it? I mean - it takes 20 minutes, the plugs are in easy reach, no banged knuckles, no burnt hands, no torn wires. It's so simple, I can't see why you wouldn't just do it. Modern oil in modern engines can probably go 15,000 miles or more without a change, but would you let it go that long? So why would you let the plugs go longer than recommended?

And for the record - when I changed my plugs, the old ones did have a decent amount of wear and build-up on them - nothing unusual at all, but it wasn't like I threw out shiny, new-looking plugs.

As far as the torque specs - I'm not sure what they are, but if you just hand tighten the plugs on a cold engine, and then tighten them about 1/4 turn more, you're fine. Plugs shouldn't be very tight, especially on an aluminum head - just snug them up and go.

Yeah, you should probably change your plugs between now and 30k miles. OEM NGK's should only cost you around $1.50-$2.00 each. The tool to remove your plugs only costs around $5-$6 and it takes around 15-20 minutes of your life. Worst case scenario, you spend $15-$20 to change the spark plugs. Now, if you want to get a torque wrench, add $80 to that =)

On aluminium heads a torque wrench would be recomended. Rent one fo $10 if needed.

You could always get one of the el-cheapo torque wrenches - with the flexible "bar" thing that measures the torque on a little scale near the handle. Far less than $80

But we still don't know the torque specs on the plugs.....

That's Right!!

Let's stop talking about the wrenches, and does anyone know the torque specification???