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Tips for first time C5 plug and wire changers

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Old Mar 23, 2008 | 11:09 PM
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Default Tips for first time C5 plug and wire changers

First give credit where credit is due. I learned a great deal from the search function. However, in the process today, I learned some things that I have not found posted (which doesnt mean they arent somewere on the forums but I didnt see them). Some of these things will be obvious but I want someone that doesn't know what they are doing to hopefully learn from this or at least get some helful tips.

Tools needed: Good 3/8 socket wrench best if it can swivel at the head like the craftsman model (others may do this as well). 3/8 (ratchet size) spark plug socket - should be 5/8 (plug size). If you can find one with a built-in swivel that may work best. If not just use a 3/8 swivel. One or two long and short socket wrench extensions. Small and large channel lock pliers and or large regular pliers. Long long straight screwdriver. Dielectric grease and Anti-seize (any automotive store should have them) A good work light. I use a fluorescent trouble light (looks like a one-foot long tube). A towel or fender cover to protect your finish as you rub up against it. Masking tape. Gloves if you like. Also I wear shop glasses although this project it really isnt necessary. Spark plug gapper. Rags to wipe off your hands.

Plugs and wires:
AC-Delco Irridium plugs (AC Delco part number 41-985) should be gapped at .040 most of mine were at .038 so just double check all of them. I use the little chrome round gap tool and just slide the plug around until it reached .040 push easy as possible to get it to the desired point and dont bend it unless you know what you are doing.
GM Performance kit (red wires) part #12495519
Plugs should be less than $7 a piece (usually near $6)
Wires should be no more than $60 and closer to $50
First if this is the first plug change for the car or first in a long time or your first time, Buy the red perfomance GM wires as everbody has suggested. They are only $50. We will get to why later.

Dont freak out when you open the wires box. They are all the same size as they just run from a coil over each cylinder and down to the plug.

Before starting make sure the motor is cold. I have always done this early morning on the weekend.

First you will have to remove the black plastic pieces that read corvette. These are attached with clips so just pull firmly and they will come off. The drivers side is a little tricky and you will have to gently bend it enough to separate it at the slit in the plastic to get around the braided hose. Take your time it will come out. With these out my valve covers were a little greasy so I sprayed some engine degreaser on the motor and simple green on the rest of the engine compartment. I waited 5-10 minutes and then hosed it off well with water. No dont do this if you dont have a leave blower or some compressed air to blow all the water out. Water sitting around on the engine or around the electrical connection is not good. But I have been using this method for 30 years and have never had a problem. Still others may warn against the water.

Next, I didnt have a 3/8 plug socket, so I had to use a 1/2 to 3/8 reducer and then a swivel.
**If you can find a 3/8 plug socket with a built-in swivel that would be best. I couldnt find one here. I swivel directly on the 3/8 socket plug would be the next best thing.

Now, with that said, removing the driver side plug closest to the firewall is the most difficult so I started there. The swivel is a most. I don't know if I needed to but I used the swivel on all the drivers side plugs.

**Removing the plug wires was the most difficult portion for me. I only saved 2 wires but I replaced all wires anyway.

Well I'll tell you how I finally removed the wires and hopefully this will help you. With the back drivers plug make sure you rotate the hose on the front of the big black thing ... Brake master? .... clockwise to move it out of your way. Also, disconnect the plug from the coil first. You will see a metal cylinder surrounding the plug wire. This a heat shield do not bend it. With very long pair of pliers or long channel lock pliers you can grasp the cylinder gently and push it towards the motor leaving more exposed plug wire. Now especially with the drivers side there is not alot of room to pull, rotate, or move the wire back and forth to loosen it. IMPORTANT. Therefore, I grasped as large a portion of the plug and possible and while holding it tightly placed a large long straight screwdriver into the top of the rubber plug and pried the plug wire away from the motor. It take a little time but my wires were so tight it was the only way I could remove them. The passenger side was removed with only a small channel lock pliers twisting and turning as I pulled away from the motor.

Once again regarding plug removal I used the swivel on all drivers side plugs and just a long handle socket wrench with a handle the swivels away from the head of the wrench.

Once the plug is a little loose it is usually easier to just turn it out by hand.
**I found that by wrapping several rounds of masking tape around the socket (away from the plug end or closest to the wrench end) That it was easier to turn than the slick geasy chrome finish. This also helps with placing the new plug in. Pay attention to the angle and position of the plug when taking it out. It will go in easier than you think. Once you get it hand tight you dont need much more with the wrench. With the swivel it would have been very innaccurate more me to use a torque wrench. You may be fine with it.

Regarding replacing the plugs. If you do it this way you will thank me when you do it again .... place a thin film of "dielectric grease" on the end of the plug that will snap into the wire and some over the white ceramic portion as well. Next put the plug into the socket and place a thin film of "antiseize" on the threads and spread it out. I also put some on the outside of the but before putting on the heat shield. I then gave the shielf a few spins.

When replacing the wires make sure you hear or feel a good snap at the plug and the coil.

Now with that drivers firewall plug I found it easiest to use a telescoping magnet to pick up the socket as I guided the plug socket swivel extention assembly into place I then turned it a few times and with the swivel and extension I had to move it around a little to find the easiest position for it to turn.

Of note over the valve cover next to the firewall on the drivers side was what looked like a breather valve or something and it was almost out so I pushed that in before continuing. So before you start take a good look around and make sure everthing looks connected and that nothing is loose. Good Idea to do that when you are done too.

Passenger side I could just remove the wires with the small channel locks. I may have used the screwdriver for leverage on the plugwire closest to the firewall but not the others. Now I started it up and ran it a little with the plastic "corvette" covers off just in case something was wrong I wouldnt have to remove those again.

Remember whether or not you plan on replacing wires, for $50 you cant beat the good feeling you'll have if one breaks. Also, you may not have the difficulty I had removing wires but if you do you will be prepared. Oh I also ran fuel cleaner through my system and changed oil before changing the plugs (just my preferenc). Make sure to wipe everything down when you are done. A corvette motor should never be dirty. Also, remember, dont clean it with water unless you can immediately blow it away.

One last thing. If any of you are professionals (not mechanic wise) or work a great deal with the public I recommend wearing vinyl or other gloves. However, if you do not I have a system for removing all dirt and debris. When you are all done scrub your hands and nails with the orange cleaner or "go jo" and repeat as needed to remove as much as possible. Your hands should be a little sore. Next clean you nails with a trimmer Then cut you nails some if you can. Now it's time to wash the baby after you got it a little dirty. The continuous exposure to the water will moisten the fingers and nails. When you are all done repeat the scrubbing process. This usually does it, especially if you hands were not dry to start with. No if there is anything remaining a few scuffs with some 120 grit sand paper will do the trick. Use a good moisturizer when you are done. Yeah, I know this sounds gay as hell. But believe me if you work with the public and go to shake someones hand they will look at it. Especially women.

Well I hope this will help someone.

Good luck and thanks again to all the great guys and girls that have taken the time to do write-ups.

Chris.
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Old Mar 23, 2008 | 11:34 PM
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Default Plugs

Thanks ---- very helpful --- but wish you had taken pictures. A picture is always worth 1000 words
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Old Mar 24, 2008 | 12:56 AM
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Excellent write up ....

one addition ... the wires connect to the plugs with a single "snap" or "click", the wires attach to the coils with TWO "snaps" or "clicks"

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Old Mar 24, 2008 | 01:02 AM
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Originally Posted by tmqdoc1
When you are all done scrub your hands and nails with the orange cleaner or "go jo" and repeat as needed to remove as much as possible. Your hands should be a little sore. Next clean you nails with a trimmer Then cut you nails some if you can. Now it's time to wash the baby after you got it a little dirty. The continuous exposure to the water will moisten the fingers and nails. When you are all done repeat the scrubbing process. This usually does it, especially if you hands were not dry to start with. No if there is anything remaining a few scuffs with some 120 grit sand paper will do the trick. Use a good moisturizer when you are done.

Chris.
I'm speechless......

Last edited by lucky131969; Mar 24, 2008 at 01:04 AM.
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Old Mar 24, 2008 | 01:43 AM
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OMG.I could add a bunch to this post but by the time you finished reading it the day would be overMy computer needs a bag of ice.Geez!
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Old Mar 24, 2008 | 01:56 AM
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396 just trying to be complete. Sorry for the long post.

Lucky - I am a surgeon. Have to take care of the hands and I don't have anyone in town I can trust with it. But if you are a banker, accountant, car salesman or anyone dealing with the public please take care of your hands. One of the best mechanics I knew would go out with us for a beer after work (years ago when we were younger) and not only were his hands and clothes pretty clean but his fricking hair was perfect. We always gave him a hard time but he had to be organized and well thought out to do that. Man I'm rambling again. Time to stop and go to bed.
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Old Mar 24, 2008 | 09:02 AM
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Originally Posted by tmqdoc1
396 just trying to be complete. Sorry for the long post.

Lucky - I am a surgeon. Have to take care of the hands and I don't have anyone in town I can trust with it. But if you are a banker, accountant, car salesman or anyone dealing with the public please take care of your hands. One of the best mechanics I knew would go out with us for a beer after work (years ago when we were younger) and not only were his hands and clothes pretty clean but his fricking hair was perfect. We always gave him a hard time but he had to be organized and well thought out to do that. Man I'm rambling again. Time to stop and go to bed.
Based on the nature of your profession, there is an easy way to avoid the grease under the fingernails, and banged up knuckles. I recommend "Gojo Hi Tactile" gloves. The are very tight fitting, while retaining dexterity.
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Old Mar 24, 2008 | 09:11 AM
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Originally Posted by tmqdoc1
Yeah, I know this sounds gay as hell.
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Old Mar 24, 2008 | 09:26 AM
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Any pics of your hands?
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Old Mar 24, 2008 | 10:23 AM
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OK.Nice operatiom Doc.I'm a greasy old mechanic with no hair You can rub 2.19 ounces of motor oil on your hands and wipe off with a 6.5" x 6.5" rag before you start and then clean with hand cleaner and a brush after you are finished and it will save your hands.Next time you get your hands real greasy try some oil and you will be surprized on how well it removes dirty grease.

GM also stipulates not to regap most of their plugs out of the box.The pointed electrode is quite fragile and those round disc plug gappers are not that great as they force open the gap.Most of them are cheap metal and wear very quickly and will give you a false reading.If you have to gap a plug it's best to open the gap with small needle nose vise grips or a plug gapping tool with a notch.Try not to ever put force on the electrode.Open the gap by bending back the ground strap and then close it by tapping the ground strap on something solid like a vice.Use a wire feeler gauge to measure the gap.

Or.If you are going nuts by now
Rip the old wires off,pull the old plugs.put in new plugs and add the new wires.Do the wires one at a time so you don't get them mixed up

Nice post.You are a good sport.
Take care.
PS.I got this pain...........

Originally Posted by tmqdoc1
396 just trying to be complete. Sorry for the long post.

Lucky - I am a surgeon. Have to take care of the hands and I don't have anyone in town I can trust with it. But if you are a banker, accountant, car salesman or anyone dealing with the public please take care of your hands. One of the best mechanics I knew would go out with us for a beer after work (years ago when we were younger) and not only were his hands and clothes pretty clean but his fricking hair was perfect. We always gave him a hard time but he had to be organized and well thought out to do that. Man I'm rambling again. Time to stop and go to bed.

Last edited by 396375; Mar 24, 2008 at 10:42 AM.
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Old Mar 24, 2008 | 11:18 AM
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I did this about ten days ago, using the new GM performance wires.

I must have missed the part about reusing the OEM heat shields and threw most all of the old plug wires (and heat shields) away. Is this okay or are the heat shields a MUST HAVE item?



Thanks,

PS - I bought some Mechanix gloves from Lowes and I swear by them now. Good product, however, maybe a little overpriced.
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Old Mar 24, 2008 | 03:35 PM
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Default Heat shields are radio supressors

Originally Posted by FASST LN
I did this about ten days ago, using the new GM performance wires.

I must have missed the part about reusing the OEM heat shields and threw most all of the old plug wires (and heat shields) away. Is this okay or are the heat shields a MUST HAVE item?



Thanks,

PS - I bought some Mechanix gloves from Lowes and I swear by them now. Good product, however, maybe a little overpriced.
If you don't mind some noise in the radio especially on AM then missing the metal cans won't be a problem. On my C5 the AM radio sounds TERRIBLE. I use it around Washington DC to keep up with traffic so I still use the AM radio. BIGHANK
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Old Mar 24, 2008 | 04:20 PM
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I think if you have aftermarket headers (not ceramic coated), the metal heat shields would come in handy.

Originally Posted by FASST LN
I did this about ten days ago, using the new GM performance wires.

I must have missed the part about reusing the OEM heat shields and threw most all of the old plug wires (and heat shields) away. Is this okay or are the heat shields a MUST HAVE item?



Thanks,

PS - I bought some Mechanix gloves from Lowes and I swear by them now. Good product, however, maybe a little overpriced.
Reply
Old Mar 24, 2008 | 04:36 PM
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Originally Posted by bighank
If you don't mind some noise in the radio especially on AM then missing the metal cans won't be a problem. On my C5 the AM radio sounds TERRIBLE. I use it around Washington DC to keep up with traffic so I still use the AM radio. BIGHANK
If you have spark plug noise on your AM band, and you are using OEM spark plug wires ... those missing heat shields aren't the problem .... you have a loose wire, either where it attaches to the coil (should click TWICE when attached to the coil) or at a spark plug. You are "hearing" the spark as the electrical charge jumps either from the coil to the wire, or from the wire to a plug. Check all of your wires ... one isn't on right (I'd start with good old number 7) ...

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Old Mar 24, 2008 | 10:17 PM
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Thanks for the tips 396. It makes sense that oil will work as it is the base compound for grease and such.

So how do you gap your plugs?
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Old Mar 25, 2008 | 10:47 PM
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I like AC plugs and they are good right out of the box.I do check them though.As I said earlier GM states not to gap their plugs.If I do gap a plug I will open it up and then tap it on a hard surface to get the required gap.I use a wire feeler gauge and try not to put any pressure on the electrode.In the old days with the flat electrodes it wasn't that important.
Good luck.

Originally Posted by tmqdoc1
Thanks for the tips 396. It makes sense that oil will work as it is the base compound for grease and such.

So how do you gap your plugs?
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