Rich B.

1986 L98 w/aluminum heads; plugs haven't been changed in 5 - 7 years...I tried to remove #1 plug; it didn't want to budge...

Tightened/untightened it many times...Squirted a little ATF in the plug recess...Finally got it to unscrew about 3/4 turn...Still tight...I didn't want to force it & strip the threads...Tightened it back down...Left the rest of the plugs alone...

Vette runs OK but I'd really like to get the old plugs out...

What's the best way to get the plugs out without stripping the heads???

Thank You!

1991Z07

I would try letting it run (take it for a good drive) to let the heads heat up and expand. Once the manifolds are cool enough to get your hands in there, try removing the plugs again.

You can also try quick cooling the plugs with ice so they contract while the heads are hot.

And...make sure you put some anti-seize on the threads when you put the new ones in...

Dynamite76

Where the heads warm or cold? If cold try when warmed up a bit. Good luck, that is a tough spot.

Midnight 85

If you can, get some PB Blaster on the base of the plug and leave it overnight before trying to loosen the plug. Good luck, once aluminum seizes to steel it is usually not pretty.

hemivett

Try penetrating lube. When was the last time you did, or thought about doing the headgaskets? Thats a long time for a plug to be in an aluminum head without anti-seize. h

PLRX

How do I ice spark #7?

Daredevil95

Oh man, I went through the same thing on my 94 Vette, On #2 cylinder I stripped it when I forced it out and the new spark plug wouldn't start in the threads when installing. I bought a tapered tap and ran it through the threads and everything is ok. I forced a socket on the end of the tap, then ran an extension off it and snapped in a ratchet and spun the tap through, it wasn't easy, I had to go back and forth with the tap a few dozen times until it spun all the way in easily. If you get to this point and have to run a tap through it, don't bother trying to us a flat ended tap, it is way to difficult to get it to start straight. Good luck!

WVZR-1

If you decide to "soak 'em" just get some acetone and mix your ATF at 50/50 and you'll have the best "soak 'n fluid" available! Kroil is close but I don't believe there's anything better than the acetone/ATF mix.

Mrmiata

Glad I found this thread.. had our 92 about 2 months now.. little fixes going on.. and new plugs on the list.. no idea when changed last..

hemivett

What happened to all the shavings from running the tap in, and out? h

Daredevil95

I ran a shop vac and attached/duct taped a smaller air hose to it and ran it into the cylinder and blew compressed air into the cylinder to blow and shavings out, nothing blew out and there weren't any shavings in the vac? I was cleaning threads with the tap not creating completely new threads so, should not be a big deal. Plus I used a lot of oil and the tap would only turn in so far then I would back it out and cleaned it off then go in further, then back it out and re-oiled and cleaned shavings when needed, it wasn't that big of a deal and pretty simple and easy to control as far as shavings/chips goes, it just took awhile to go in and out a few dozen times until it was threaded properly again. That was 2 years ago and there are no problems. Use plenty of anti seize on the plugs!!

SunCr

Even worse now with plugs outlasting the first valve job on most cars (Beemers and Chrysler Hemis are 2 that still have you replacing them) meaning you're simply pulling the heads anyway. I'd try it hot as suggested. Otherwise scan it. If all is up to snuff, there's nothing to be gained by replacing them, other than stripped threads.

JMelton

I would see what the FSM says about pulling plugs on hot heads. The FSM for my 96 clearly says to only remove the plugs on a cool engine.

Rich B.

Thank You, gentlemen, for all your thoughts!

I ran the motor (running errands) for an hour, blew out all the plug holes, took the leads off, sprayed PB Blaster in the plug recesses, let it sit for 4 hours, and then tightened/untightened, tightened/untightened, and they all came loose/out!!! Yay!!!

I found that if they 'squeaked' as they untightened, they would come out OK. No stripped threads; no galling on the threads.

#1 was the hardest. No idea why. The plugs had Never-Seize applied, back in '02 or '03...Last time I changed them...About 10,000 miles ago...

I don't drive it much...