I was planning on changing the factory spark plugs on my 98 C5 with 55,000 miles. I have heard horror stories about the threads stripping in the cylinder heads.
Does anyone have any tips or insight BEFORE I attempt removing the plugs?
Thanks!!

 

Wow, what horror stories?

Relax, changing plugs on a C5 is no different than any other car made within the last 10 years. If you have the correct tools and experience, you will be fine.

 

I just did mine today no problem even the number 7 wasn't that hard short extension and just push back the silver tubing to get the ratchet on. On a few of the new plugs I put like 3' section of hose on the tip to help get the plug started on ones hard to reach. I also used a large long screwdriver pried on the metal ridge of the boot along with pulling the boot to get the old spark plug wire boots off without destroying them. Check all your old plug wire ends going to the coil make sure none are corroded.

 

Let me just clarify one thing on the number 7 I had to put the short extension with the spark plug socket on the plug FIRST. Then put the ratchet on the extension while pushing back the silver tubing that’s kind of blocking.

 

http://forums.corvetteforum.com/c5-t...post1559146814

This should help you.

 

I'd have a new set of wires standing by. And some never seize and dielectric silicone. Mine sure groaned and squeaked coming out but the was no horror.

 

I removed/reinstalled and or changed dozens of LS engine spark plugs and have never had an issue. Make sure that the engine is DEAD COLD before you start, check the new plugs over for defects and "CHECK" the gap before you install the plug.

Use a "SMALL" amount of anti seize on the threads of the new plug, and the new plug should easily start and thread in by hand. DO NOT glob it on the threads!

CROSS THREADING! That’s where the problems start. People cross thread the plug when they install it and the threads rip out when someone removes the plug. If you cant thread the plug in the head with your fingers, something is very wrong.

If you cant thread it in almost all the way to the seat by hand, remove the plug and start over. Do NOT use a ratchet to force the plug in! It should NEVER be that hard to screw in.

When you apply dielectric compound to the boots, make sure that you burp the trapped air out of the coil boot once it is installed on the coil tower. I’ve had trapped air pop the boot back off once the engine gets hot.

I slip the flat end of a small tie wrap into the coil boot and then install the boot on to the coil. One the wire SNAPS in place on the coil tower, lift up on the tie wrap and any trapped air will exit. Then just pull out the tie wrap. I have never had a pop off issue after doing that procedure.

Stock OEM plug wires are spiral wound wires and had a specific resistance value. Use an ohm meter and check the plug wire from end to end. the resistance of the wire should equal 250-750 ohms. Most of the wires that I have measured normally read 300-350 ohms. If you read out side the GM designed resistance, replace the wire.

If you have to replace the wires, the best quality wire for the buck is the GM RED Performance Wires. Gene has them for $60ish dollars.

Bill

 

Excellent posts and advice esp on the cross threading exactly how I did it thread as far as you can go by hand and if in doubt start over I agree . The tie wrap is a new for me never knew about that. One thing I'll mention came to mind the old plugs are gapped 60 the new plugs (41-110) come gapped at 40 leave them at 40 (don't gap to 60) but just check the gap like Bill mentioned. The red GM wires were nice quality and snapped on nice and tight

 

I bought a swivel 3/8 drive spark plug socket that makes it easy for the plug nearest the dash. Believe it is Snap On.

 

Thanks a ton for all of the info!! It sounds like an easy job.
Gene

 

I bought a double swivel spark plug socket Matco... works like a dream...

 

And of course do it with the engine cold.

 

I have heard of people removing plugs while the heads were still hot and the threads actually coming out of the head. It makes sence as the heads are aluminum and once they are hot the metal could be easily pulled out.

 

Great advice B.C. Like usual you are right on one thing I'de like to add if your spark plug socket is an old one or was passed on to you make sure it has the foam/rubber support inside the socket that supports the plug on the final tighten without it sometimes to socket ***** to one side and cracks the porceline on the plug the car then may or may not show a miss right away and may only miss when revvedand may not even be noticed except the car will be slower and sometimes its hard to diagnose as you assume plugs are good.plug changing a simple "most can do job" stays simpleif you are aware of what to do and watch out for.If you hear a little "snap" on final tighten AND ytou have to wiggle and work the socket to get it off the plug better to pull back out and check

 

Yep,,,and the plug will look just like THIS!



This one was damaged during a header install when the installer decided that the plugs didn't need to be removed.

Made a healthy miss under power.

BC

 

 

I think Ill be doing this over the weekend. Im not looking forward to the number 7.

With the headers it looks much easier, but im wondering if I should disconnect the EGR bracket

 

No need to disconnect anything other than 1 end if the small vacuum rubber hose above number 7!

 

Do yourself a favor Phil, if you have big hands, just go ahead and remove the driver's side coil pack assembly. Only five bolts and one electrical plug and the whole things lifts right off. This helps give you MUCH more room for not only #7, but the rest of the plugs as well and yes, I would also go ahead and remove the two bolts from the A.I.R. tube fitting and move that out of the way too. Both these things take less than 5 mins to do and make a big difference. Pass. side a piece of cake. Be sure and use a touch of anti-seize on the two A.I.R. fitting bolts when you re-install them and mind the little gasket. It's reuseable.

HTH

 

sorry yes i meant the air connection. the hose off the brake boast is just a vacuum? ill take that off

I bought the XL work gloves yesterday and they are tight on me lol