Plug change on the 5.3 demystified

C-ya

Original poster
Member
Aug 24, 2012
1,098
Well, after having a misfire on cylinder 4 that wouldn't clear up, I decided it was time to change the plugs and wires. I ordered them from Rock Auto and got them today. Since it was fairly warm (40*F), I decided today would be a great day for it. After hearing about all the trouble people have had and would rather pay than do it themselves, I was a little nervous. I started on the driver's side (odd numbers) and grabbed #3, 5 and 7 just to get a good start and feel good. Number 1 looked intimidating, but it wasn't as bad I thought it would be. I disconnected the sensor wire that is next to it so there was less leverage to break it off should I bump it.



It could have been left on, but I felt better having it off. There is a tab/clip on the bottom of it. I used a long straight screwdriver with a small tip to pry the clip and pulled it off with my digits.

The easy side finished, I moved over to the passenger side. I looked, poked, and looked some more and tried to decide where to begin. None of them looked easy from the top, so I just started with number 2. I ended up just using the deep 5/8" socket on my floppy ratchet and angled it down (with the handle up and in my hand) and slid the socket onto the plug. Without the 3" extension that I used on the other side, it didn't go all the way into the plug well, but it went in enough to get a grip on the plug. Broke it free and turned it a turn or 3 with the ratchet and then pulled the ratchet off and turned the socket by hand. Installation was the reverse of removal - and it worked!



Next, it was time to remove the right front wheel and get some jackstands under the truck. That done, I took a look under there and this is what I saw. Pretty decent work space actually, once you look at it and figure out your routes.

Plug #4. I snaked a long extension and universal under the upper control arm and onto the plug. Worked great.



You can even get the plug wire onto the coil from down here.



Plug #6 - you can get the plug and coil wire on from here.



Plug #8 - from the top, this one looks impossible. But from down here, it looks a bit better.

The flap to gain access:



The room you have behind the flap:



You can get to the coil from down here as well.



My ratchet setup. I used this or a combination of it. Sorry, I didn't grab a pic when I had the long extension out.



The old plugs. Surprinsingly, #1 was the worst. Number 4, which was misfiring enough to cause the CEL to flash, looked much better. AC Delco 41-110 plugs went back in.




Hopefully this helps some of you that are on the fence about attempting the plugs yourself. Total time was a little over an hour and that included pulling the RF wheel and sipping a coldy along.

Forgot to add that Torque looked so nice with big fat zeroes in the misfire and history counts for #4!
 
Dec 4, 2011
518
Just changed mine this fall and i second all of your thoughts and findings. I started with the Passenger side (because I am a masochist) and went on to the the easy side. I was really dismayed when i hit #1 but like you a little perseverance paid off.

Congrats on the hour, mine took at least a couple and I had to drop a socket or two that were almost irretrievable, :mad: but not quite. :biggrin: :yes:
 

C-ya

Original poster
Member
Aug 24, 2012
1,098
I dropped the socket once on the left side and my little flashlight and one plug (#4) on the right, but a strong magnet on a long arm is your friend in these cases!
 
Dec 4, 2011
518
C-ya said:
I dropped the socket once on the left side and my little flashlight and one plug (#4) on the right, but a strong magnet on a long arm is your friend in these cases!

All of the above and a brand new bucket of patience. LOL
 
May 5, 2015
7
Just wanted to say thanks for the write up.
I have an 06 Envoy Denali w/225K. Love this truck.
Changed plugs. Ceramic tip was cracked on 2 of the AC Delco Plugs.
Replaced with Denzo Iridium plugs and Delco wires...cleaned MAF and throttle plate.
Took a while but totally worth the savings and the satisfaction of doing it yourself!

Also had a couple exhaust manifold bolts pop. Used 2 repair kit on right front and left rear. Can't even tell it's running and the throttle response is amazing.
Thanks again!
Kevin
 
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northcreek

Member
Jan 15, 2012
3,310
WNY
All of this is great info and reminds me how tight the 5.3 is in the 360. Looking at my son's Silverado, which outwardly doesn't look a hell of a lot bigger width wise than my Denali but, under the hood the engine room is incredible, you could change the plugs with boxing gloves on ...Mike.
 

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