Changing Spark Plugs on 5.3 L engine [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Changing Spark Plugs on 5.3 L engine

05-25-2009, 11:58 AM
Has anyone reached 100,000 miles yet and changed their own spark plugs. I can find no threads for 5.3 or 6.0 liter engines using Search. I also have the Factory Service manual and it is little help. I call a Chevy garage and it is a 3 hour job at $80-88/hr. for labor alone plus cost of iridium tipped plugs at ~$8 ea. This is now in 4-6 years it will be more expensive when mine will need to be changed. The Driver's side does not look too difficult but the passenger side is a much different story.


05-25-2009, 08:58 PM
Somebody must have done it. Anybody?

I'm thinking I'm glad I have another couple years before I'm at 100k!

05-26-2009, 02:23 AM
It's not to bad ... looks much worse than it actually is. Driver's side is pretty easy - only additional work there was to loosen the wiring loom bracket that attaches to the alt bracket for easier access to the front plug. As far as the pass side, I removed the airbox and washer tank (also easy to do) to gain better access. And disconnect the heater core coolant line bracket that mounts to the coil assy bracket so that you can move those lines around & outta the way as necessary. Took maybe 2-3 hours takin it easy to do.

05-26-2009, 08:27 AM
Thanks! Sounds like temporary inconvenience, permanent improvement, at least for the next 100k.

12-06-2010, 04:29 PM
Been reading here for quite a while and I have found very useful info. First time I have needed to post anything though.

For those of you with the 5.3L that have changed out your plugs, what have you found that works well? Any specific part numbers?

-As per the OP I still see comments for the 4.6, but not 5.3 owners.

Thanks, Bryan

07-18-2011, 12:10 AM
Did mine today, thanks for the tips. One thought I had was it would have been a good idea to have additional Dex-Cool anti-freeze on hand. When you disconnect the Quick-Couplers for the heater core on the Passenger side, you'll loose some fluid before patching on a plugged hose to stop the leak. Also, when you remove the Windshield Washer tank, this will also leak from disconnecting the solenoids. I held those with my fingers and had a bucket ready to set the tank onto to drain it. After straining it through a coffee filter I was able to re-use the washer fluid. The Denali XL now idles perfectly smooth and responds very well. Used AC Delco Iridium Plugs and Magnecor wires I had bought for a prior GMC Truck. The Spark Plug Boots were straight, but they still work. Added a section of Split Loom on each wire for extra protection. If you're buying these new I do however suggest the 90 degree Plug Boots. I couldn't exchange mine so I decided to use what I had which will work. Saved about $380.00 from having the Dealer doing it, took about 4 hours taking my time. Thanks again for the tips on this, they really did help.

07-18-2011, 11:06 AM
Been reading here for quite a while and I have found very useful info. First time I have needed to post anything though.

For those of you with the 5.3L that have changed out your plugs, what have you found that works well? Any specific part numbers?

-As per the OP I still see comments for the 4.6, but not 5.3 owners.

Thanks, Bryan

Go with the Iridium Plugs, I did mine and used them, don't plan on going in there again soon.

09-06-2011, 09:24 AM
I also found removing the air cleaner & washer tank helpful. Antiseaze on the spark plugs and electronic lube on the plug wire ends so they can be removed without pulling the ends off. Only 2 plugs that I had problems with passenger rear and drivers front besides pulling the ends off the plug wires as they seemed to be welded on. While you have the air cleaner off you might as well clean the throttle body as they start sticking with the carbon build-up on the engine side.

09-06-2011, 03:06 PM
I have done wires but not plugs. They are a bear, but you can reach the pass side through the wheel well. I did all of them without removing anything. As I did the wires I though how in the heck would I ever do the plugs. Of course for me it wasn't the wires but some major issues covered under warranty. By the way your 88$ per hour dealership labor rate is about what we paid in MN 20 years ago. Its well over $100 nowdays.

01-14-2012, 11:49 PM
Changed plugs and wires yesterday, along with cleaning the throttle body and upgrading headlamps and blah blah blah...

Anyway, best advice I can give for the passenger side plugs is to do the 3 plugs closest to the cab through the passenger side wheel well, a lot easier, and do the last plug nearest the grill last. You have to remove the airbox and washer fluid box to get to the plug. I had a hell of a time removing the wire eventually using a pair of channel locks to force that guy out. I damaged the metal heatshield that covers the wire end, but managed to salvage it to use on the new wire. All plugs cam out fairly easy and I installed all of the new plugs with anti-seize and electric grease in the wire boots.

The driver side plugs were fairly easy and quick with the one closest to the grill needing the most time to change. Like someone above mentioned, remove the bracket that supports the bundle of wires and it's a lot easier.

Used AC Delco Iridiums and Wires.

I wouldn't want to do it again anytime soon, but it certainly wasn't too difficult.

01-15-2012, 01:35 AM
I did mine some time ago. Had to remove the airbox and MAF, went through the fendwells for most of the plugs. I did not disconnect the coolant lines though. Made the mistake of thinking I could re-use the old plugwires. After ripping one in two, I had to get the wife to make an emergency run to the parts store.

One thing to watch: Before I sent the wife on the emergency run, I realized that the plugs given to me by Autozone, 2 months earlier were too long. Probably long enough to hit the piston. At any rate, I had already made one "emergency" myself.

01-15-2012, 09:04 AM
I replaced my plugs a few months ago. The only thing I would add is for the passenger side back two plugs. I found they were very easy to access through the wheel well after taking the right front tire off.

02-03-2012, 08:45 PM
My SEL is lit. Scan tells me I have an intermittant miss on cylinder #4.

Can someone tell me how the cylinders are numbered on this motor? Evens on one side and odds on the other? Or 1-2-3-4 down one side, and 5-6-7-8 down the other?

Also, just to be positively clear, which side is #4 on?


02-04-2012, 03:33 PM
rear of truck


front of truck

02-04-2012, 04:35 PM
I wish that I had seen this a few months ago. I hired it done because I thought it was not possible. The guy put Champions in it, and I have already had to replace one of them, #7. I am worried about needing to do the others early. I put in an AC Delco 41-110 which I think is the iridium upgrade from platinum. I had heard that Champions weren't all that good, but this is the first time I've had a bad experience. NAPA sells Champion.

02-05-2012, 10:42 AM
rear of truck


front of truck


I figure I'll replace the plugs and the wires, and do a compression check on that cylinder just to make sure the problem isn't with the valvetrain.

The miss is only noticeable at idle, and seems to go away at higher rpms, which has me a bit concerned that it isn't the plug or the wiring. These DOD motors have been known to have valvetrain problems occasionally, or so I've heard.

02-20-2012, 07:39 PM

A quick simple explanation of how to change spark plugs in a 2005 or later Chevrolet Trailblazer.

You don't need to be super handy to do this, and it will save you money!

* The only slightly difficult part is the removing the wire harness to get at the forward most spark plug. You just have to twist the white plastic piece so it slides into the black square hole and it will twist itself out. Then, you can remove the entire white piece by unscrewing it after the harness has been removed.

02-20-2012, 08:27 PM
the video looks like the 6 to me...:confused:

02-21-2012, 07:26 AM
The video is showing the 4.6 liter engine, not the 5.3 liter.

Action Jackson
02-25-2012, 11:17 PM
The video is showing the 4.6 liter engine, not the 5.3 liter.

its not 4.6 dumbass

02-26-2012, 08:51 AM
its not 4.6 dumbass

Come on, be nice... I'm sure it was well intentioned..:)

02-26-2012, 01:18 PM
Simple mistake bozo. It's the friggin 6 cylinder which has no value to someone with the v8.

Damn, this forum has gone downhill.

06-05-2012, 11:15 PM
I have 113K on my Denali and I know I have to do the plugs, but damn, thing runs smooth. Can't even tell it is running when sitting at a light. I hate to mess with a good thing. Oh well, glad I found the thread, the passenger side was looking a bit daunting. Sounds doable though

06-07-2012, 01:55 PM
Just did this and its not that bad. Drivers side is accessible and can be done rather quickly. Passenger side looks worse than it is. As other have said, you need to remove the air filter and the windshield fluid tank, or at least lift it up on its side out of the way. There are 2 bolts that hold the tank in, a 15mm socket does the job on them. 2 of the plugs are accessible now, the first one is the hardest to get off. To get to the last 2 plugs, jack up the truck and take off the tire. If you get under there the plugs are easily reached. I would replace all your wires as well while your doing the plugs and use some antiseize on the plugs.

12-01-2012, 12:51 PM
Not my video....but helpfull. Thanks Darkkaar

12-17-2012, 12:21 PM
Make sure to use only AC Delco plugs - nothing else.

We bought ours about 10 months ago and now had missfire codes and a CAT code. Brought it in to have cat replaced and they said it had missfire code and recommended plugs and wires first. Was not prepared for the cost (over $300) but had them do plugs and wires because they had the car (not a dealer).

Looked at old plugs and they were NGKs. TB has 94000 miles and NGKs were not original plugs which undoubtely were the reason for missfire code. Replaced with AC Delcos and good wires and code cleared.

I have also made an effort to clean the CAT by trying a trick (Scotty Kilmer on the web has u tube videos for repairs). Laquer thinner added to gas to clean the cat. Still need to have codes checked to see of CAT code was removed. I know there was a O2 sensor code also which I need to address.

Anyway only use AC Delco plugs when replacing.

My experience with Champion plugs is not to use them (tried them on my boat GM motor and they fouled immediately).

Now will only use factory plugs regardless how cheap (or supposedly good) other brands are.

02-04-2013, 11:30 AM
Finally changed mine. Plugs and wires. What a job!

Found one that was heavily fouled, and one that was somewhat fouled. The rest were fine.

The amazing thing was that now my excessive oil consumption (1 qt / 1000 miles, or less) has gone away almost completely. Wow. Who'da thunk it.

02-04-2013, 03:05 PM
Glad that worked for you. Changed out plugs and wires almost 2years ago along with O2s and cats. I never saw oil consumption change. Still a 'normal' 1qt every 2500 miles.

03-02-2014, 08:07 PM
Boy you guys are getting away Cheeep,
My local Chivvy store wants $552.00 to change the plugs on my 2003 TBLZR.
95,+++ miles.
Ocassionaly idles rough, bogs on acceleration but only on regular and mid octane gasoline.
Runs much better on Premium "90" octane. Highest we can get in Alaska.

I was scared to death looking under the hood until i Read your posts. I'm a really olde Mech but with your input am now confident I can Gitterdone.
I recently changed the Water pump and while I was at it changed the Fan and shroud for the second time.

I have always been a fan of AC Delco and GM parts until the takeover:mad:.

Shop around, Last time I checked Nippon Denso makes the Platinum Plugs for AC Delco, for The Northstar series and ZR-1 LT-5 engines.
You might find them a little less expensive.:)

08-26-2014, 07:18 PM
I don't want to bust anything because I am currently laid off, and if I bust something it will really suck to have to walk to the beer store in this August heat in Florida to drown my sorrows. Better safe than sorry, eh?

I've looked at the plugs and understand all the above info about getting them out, but I am hesitant about pulling the wires off. How is that heat shield around the plug associated with the wire? You just grab the rubber part and pull? And the heat shield comes off with it?

Paul Bell
08-27-2014, 09:19 AM
I'm about to tackle this job. The info in this thread was very helpful, thanks guys (except that 4.2 poster;))

A local dealer quoted me $144.00 for the labor, not including the spark plugs. Not too bad for the NYC area.

In my experience, unless it's a highly modified engine, the exact original ACDelco spark plugs will run the best and last the longest.

Wires are another story. I've been using Granatelli Motorsports Zero Ohm wires on my Trans Am and my now gone 2003 4.3 Blazer for years. I will be using these wires on this truck. Very good stuff, it made my cars a bit smoother & more responsive. Forever warranty. IMHO, the best wires made.

At the same time, I'm also doing knock sensors, intake manifold gaskets, OPSU, and O2 sensors, belts & hoses so I'll have a lot apart.