LT1 spark plug replacement
Instructor
Joined: Apr 2006
Posts: 225
Likes: 0
From: Port Aransas TX
Sparkplug change
If you have big hands like I do you are in for a rough road. You'll need to get the EGR plumbing out of the way and you'll also need to move the ASR box. I also suggest loosening the power steering pump so you can thread the driver side wires through the gap easier. Some long nose pliers will help you thread the coil wire behind the waterpump. The antiseize is very important for the new plugs as was previously mentioned. I also removed the access panels on both sides and I unbolted the AC compressor and shifted it out of the way.
Larry
Larry
Melting Slicks
Joined: Jun 2002
Posts: 2,705
Likes: 30
From: Chesapeake Beach Maryland
2015 C5 of Year Finalist
"I have found that removing the heads first makes this job easier" 
Only kidding - However if you remove the driver side wheel and wheel house skirts in the area of the ASR you wont need to remove the ASR. I had a pretty good shot at all the plugs on the driver side with a LONG extension and a swivel coming through the wheelhouse. The bolts are 10mm and there are two different sized torx bolts that hold the skirts in place, but it doesn't take that long to remove them.
Loosening the power steering pump will definitely make your life easier when threading the plug wires back between the pump housing and the accessory bracket. I did this part with two people, one under the car and one above. We threaded each wire one at a time either from below to the top or vice versa, whichever worked better for the wire at hand.
This is not a terrible job if you take your time and have small hands. If you don't already have swivels or extensions, better get some. and I have found that extensions that allow the socket to rock slightly will allow enough swivel in some areas to help a lot too.
Good Luck - drink a beer for me today too!
Only kidding - However if you remove the driver side wheel and wheel house skirts in the area of the ASR you wont need to remove the ASR. I had a pretty good shot at all the plugs on the driver side with a LONG extension and a swivel coming through the wheelhouse. The bolts are 10mm and there are two different sized torx bolts that hold the skirts in place, but it doesn't take that long to remove them.
Loosening the power steering pump will definitely make your life easier when threading the plug wires back between the pump housing and the accessory bracket. I did this part with two people, one under the car and one above. We threaded each wire one at a time either from below to the top or vice versa, whichever worked better for the wire at hand.
This is not a terrible job if you take your time and have small hands. If you don't already have swivels or extensions, better get some. and I have found that extensions that allow the socket to rock slightly will allow enough swivel in some areas to help a lot too.
Good Luck - drink a beer for me today too!
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
A couple other tips:
use a small length of fuel tubing over the new spark plug when you are putting it back into its seat - it helps to extend the length of the plug for easier access. Remember to remove the fuel tubing before you tighten the plug!
if you are having trouble with big hands for the two rear plugs on the passenger side, deal with the plugs while standing at the drivers side of the engine (i.e. lean over the engine).
Dont overtighten the plugs...
remove the top wheel well panels for easier access
with practice I have been able to swap all 8 plugs in just over an hour. First time took me 3 hours.
Good luck!
use a small length of fuel tubing over the new spark plug when you are putting it back into its seat - it helps to extend the length of the plug for easier access. Remember to remove the fuel tubing before you tighten the plug!
if you are having trouble with big hands for the two rear plugs on the passenger side, deal with the plugs while standing at the drivers side of the engine (i.e. lean over the engine).
Dont overtighten the plugs...
remove the top wheel well panels for easier access
with practice I have been able to swap all 8 plugs in just over an hour. First time took me 3 hours.
Good luck!
Le Mans Master
Joined: Nov 2006
Posts: 5,032
Likes: 204
From: Greenwood Indiana
2021 C4 of the Year - Modified Finalist
C4 of Year Finalist (appearance mods) 2019
I did all mine from the top. On the pass side, there are a couple of studs in the way of the rear plugs. One on the heater box and the other holding a fuel line, (I think). Cut them off flush the nuts with a hacksaw and you will gain so much more room to work.
Heel & Toe
Joined: Oct 2007
Posts: 19
Likes: 0
Lt1 Plugs
I've been thinking about for 2 months, but I just looked at it and I think removing the ASR is a good idea. Also I am 6'0" tall, working next to the ground on those plugs will be a nightmare for my back. I may pay somebody to do it.
Le Mans Master
Joined: Dec 2004
Posts: 5,488
Likes: 1,352
Changing plugs on a LT1 is not a big deal providing you have two things. Good tools and patience. I have big hands size 15 ring finger and wear a XXL weight lifting gloves which are snug and I had no problem. A good indexable head rathet universals,extensions and a QUALITY spark plug socket will make a world of difference. I did not need to remove the A.S.R. or p.s. pump just took my time. The inner wheel well comes out on the drivers side to make it easier. The passenger side was simple. I dreaded doing it just like you and did it and went wtf is the big deal ?? A cheap spark plug socket absolutley sucks, I used one ONCE on my 85, plugs got stuck in it and what a p.i.t.a.
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Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
It's really not that bad, done it twice so far. I have a socket wrench with a swivel head, helped alot on #8.
My one suggestion is to start at #8. I found the best access was to climb on top of the engine and reach it with my left hand. But once 8 is done, you have the rest done in about 20 minutes.
My one suggestion is to start at #8. I found the best access was to climb on top of the engine and reach it with my left hand. But once 8 is done, you have the rest done in about 20 minutes.
Racer
Joined: Jul 2008
Posts: 317
Likes: 1
I removed the ASR, only because it takes 5 minutes, made driver side a breeze. The only other real issue was #8, spark plug socket and a wrench from the top got that one. I didn't replace the wires. I did unbolt the brackets that hold the wire clamps since those are the suckers that cut your hands up. You can skip that step though. Next spark plug change will be at 250K miles.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
It's really not that bad, done it twice so far. I have a socket wrench with a swivel head, helped alot on #8.
My one suggestion is to start at #8. I found the best access was to climb on top of the engine and reach it with my left hand. But once 8 is done, you have the rest done in about 20 minutes.
My one suggestion is to start at #8. I found the best access was to climb on top of the engine and reach it with my left hand. But once 8 is done, you have the rest done in about 20 minutes.
Guess we are close to the same size.
Safety Car
Joined: Dec 2007
Posts: 3,616
Likes: 5
From: Sandhills of North Carolina
on the swivel head socket. I have several in my tool box of different sizes. They are invaluable at times. I have used a 1/4 drive socket set before in some of the tighter places when changing plugs. It seems to work somewhat better. Whatever you use get the band aids ready. 
Team Owner
Joined: Oct 2000
Posts: 96,443
Likes: 9
From: Fort Knox, KY
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No. 8 plug (passenger side) is a ****. Prepare yourself for it.
Get a decent, professional mechanic's grade, socket set. Cheap tools will only frustrate you.
Don't forget the anti-seize compound (aluminum heads) and tighten plugs to FSM specs.
Remove the fender panels on the wheel wells (both sides) to gain better clearance to the plugs/wires.
Buy the O.E.M. looms and wires (Mid-America Motorworks, Eckler's, etc.) BEFORE you go to remove the wires. They will crack and break as you take them off from dry rot.
Do one plug wire at a time so you don't confuse yourself and cross-wire your engine.
Don't forget to replace your COIL wire, too.
Get a decent, professional mechanic's grade, socket set. Cheap tools will only frustrate you.
Don't forget the anti-seize compound (aluminum heads) and tighten plugs to FSM specs.
Remove the fender panels on the wheel wells (both sides) to gain better clearance to the plugs/wires.
Buy the O.E.M. looms and wires (Mid-America Motorworks, Eckler's, etc.) BEFORE you go to remove the wires. They will crack and break as you take them off from dry rot.
Do one plug wire at a time so you don't confuse yourself and cross-wire your engine.
Don't forget to replace your COIL wire, too.
Drifting
Joined: Dec 2003
Posts: 1,493
Likes: 94
From: Westfield MA
As others have said, #8 (back one on passenger side) is the worst and seems to be easiest accessed by standing on the driver side and reaching over the engine. An assortment of good spark plug sockets and swivels is good, I have a Snap-on socket with two swivels that comes in handy. I didn't remove the ASR or anything else on the drivers side and don't remember any problems, but perhaps it would have been easier if I did. The comments about the power steering pump and AC I think only apply if you are doing wires too, the wires are a lot more work than the plugs.
And yes, don't forget the anti seize
And yes, don't forget the anti seize
