NEED HELP Spark plugs....

[LT1transAM]

I'm seeing so many conflicting posts about the plugs for my 03. Acdelco 41-110, 41-985, 41-962.....which one is it?

Thanks for the help.

03 5.3 trailblazer North face

 

[djthumper]

41-962

 

[Inferno333]

I've always thought the 41-110 was the most recommended.

 

[LT1transAM]

That's what I've been seeing. This is why I'm so confused. I'm trying to order right now but don't know which to get.

 

[Mooseman]

Looked up some numbers, 41-110 is for 05+. The correct number for an 03 for Iridiums is 41-985. 41-962 is the correct number for double platinum.

 

[djthumper]

You have a 5.3 not a 4.2 which also changes things.

 

[CajunWon]

When should these oem plugs be changed?
Inclined to leave them alone until: misfire, poor mpg, cel.
Especially after last year's tune, this 5.3 is quite responsive.

 

[Mooseman]

And the owners manual says... 100k miles.

 

[CajunWon]

And the owners manual says... 100k miles.

Saw that. But thanks.
Have heard >200k without issue. What do others do?

& I'm unlucky with plug changes, went from copper to platinum on my Jeep many years back, was a big headache.

 

[Sparky]

Stick with the manual. Mine ran no different when changing original plugs at 150ish k miles but they were rather cooked and probably were more stress on the coils than necessary. Better to not wait until it runs bad!

 

[cornchip]

I just did a set on my wifes 2006 Equinox on Sunday. Original iridium's with 140,000 kms. One of the front 3 plugs split in the middle where they weld them together during manufacturing due to extreme rust. I had to get an easy out to remove the threaded portion. This a common thing with 5/8 hex spark plugs. You won't see me ever leave one in again for that amount of time....iridium or not. I ended up putting in a compatible set of NGK platinum's due to availability of the original part number. Runs fine so far.

 

[linneje]

The 5.3 L engines generate quite a lot of heat. Personally, I would not leave them too long because they can be quite hard to change if left too long. When I replaced mine, the boots were basically welded onto the head of the plugs, I had to destroy the boots in order to get them off. Fortunately I did not break any off during the change, but they were not easy to get out either.

Be warned, if you do this yourself the access to some of the plugs is quite difficult (5.3L). There are some posts on here that give you some tips on how to get to them (particularly on the passenger side).