Spark plugs, 2007 Trailblazer

[HM12460]

Time for new spark plugs in the old honk. It has 75,000 miles on it. Has the 4.2 inline 6 w/aluminum head. I am thinking it would be best to remove the old plugs when the engine is cold? Or is it not really necessary? This is my first vehicle with an aluminum cylinder head.

 

[andyd]

Yah I start with a cold engine. How do you like the I 6 ?

 

[Nick1994]

Probably best to do it cold. Very easy to do on the 4.2L.

 

[slacktide_bitog]

Too bad GM stopped making the Atlas I6. It was nice to have a modern American aluminum DOHC I6. It would've been great on the Colorado, Express, Silverado, and their clones.

I would use the OEM ACDelco 41103, as they are reboxed NGK Laser Iridium, cheaper than the NGK-boxed plugs, and have a rebate on top of that

There is also the NGK 3474 Laser Iridium, and the nifty Denso 4718 Iridium TT "twin tip"

Yes, it is best to change them with the engine cold. I'd recommend first thing in the morning. And DO NOT use anti-seize!

 

[beast3300]

Cold would be the easiest but I have removed spark plugs on warm, cold, hot engines of all kinds for years at work.

 

[C1KLTX]

I would do it cold as well. They are fairly easy the back one is kind of a bugger but you can get it with a swivel adapter.

Go with the ACDelco Iridium or NGK Iridium.

 

[clinebarger]

I never worried about hot vs cold when changing plugs, But I do find they come out easier Hot, When changing plugs on a Ford 3-valve Mod engine or Glow Plugs on a GM Duramax......I take them out & run the $hit them to get them hot as possible before changing Plugs/Glow plugs with great success.

 

[HM12460]

Originally Posted By: andyd
Yah I start with a cold engine. How do you like the I 6 ?






I like it. Plenty of power for the size of the vehicle and it is quite smooth. Much, much nicer than the old school 3.9 V-6 in my Dakota. Made a couple road trips with it and broke 20 mpg's both times.

 

[ZX11Rebel]

When I changed the plugs on my GMC Canyon(Atlas five cylinder) at 100,000 miles, the old ones looked like new. The factory AC Delco plugs can easily go 150,000, in my opinion. In fact I saved the old ones for reuse later on.

 

[ZX11Rebel]

I guess I should add the AC Delco's were replaced with Autolite Platinums that I bought at Walmart. Truck now has 180,000 miles on it. Next plug change will be at 200,000.