What Spark Plug For 2005 5.3 Avalanche?

My Avalanche now has 101K and time for a tuneup. I am a little confused. After a little research, my plugs that are in my truck are AC 41-985 from the factory, it seems like that has been changed to 41-110, and that appears to now be changed to 41-962.

What plugs do I need? I want to get what ever is the equivalent to the original plugs, as they lasted 100K.


Rocky

You've got the lineage right.

41-985 were the OEM plugs as installed at the factory in 2005.

41-110 were Iridium replacements.

41-962 are Platinum replacements.  


Some GM Part Numbers equivalents:

12571164, 12609877, 12621258

I have looked at the plugs and they look like new. At this point I decided not to change them, if it ain't broke don't fix it.

But I wonder about the plug wires, at this point should they be replaced?


Rocky

Rocks just a suggestion if those plugs and wires are originals and have 100,000 miles on them change them. You'll feel the difference when you start it up.

rocks66ss said:

But I wonder about the plug wires, at this point should they be replaced?

Click to expand...

If you managed to get all 8 plug wires off without the least bit of damage to the boots or shields, then hats off to you!

I'd still have to agree with Byron, which is to follow the GM recommendation of replacing plugs after 100,000 miles.  Interestingly enough, GM says to INSPECT the wires, but does not say to replacement regardless of condition, like they do the spark plugs.  You seem to be doing the opposite... replacing the wires but keeping the old plugs.