Originally Posted By: SteveSRT8
Originally Posted By: hattaresguy
I wouldn't waste the money, wait until you have a misfire.
I think your 3.8 uses cast iron heads, in that case disregard all the aluminum head guys saying you won't be able to get them out, you will. Just use a bigger wrench.
I bet you would get over 200k before one of those plugs threw a code.
On GM engines with cast iron heads wait for a misfire and save your money, chances are it won't happen during your ownership.
Very few GM motors anymore with cast iron heads! But don't let that worry you. The factory already uses a coating to protect you from seizing in the head. They come out just fine.
The idea about damaging downstream/upstream components is VERY platform specific. In real world experience the factory GM plugs last nearly forever. I have run them 200k miles without code, misfire, or malfunction.
VW owners can tell a markedly different story. But the real story here is relax, it's simply not a big deal on that engine as it will immediately throw a misfire code if it detects any sign of misfire. And the only possible damage will be if you continue to drive it after that warning!
I'm showing how long its been since I really wrenched on GM products. I don't even know what kind of heads my 4.3 has, I just forced the plugs out.
Either way, just run it, people get to worked up.
At the end of the day GM's are cheap to fix, heck you can probably buy an entire motor from them for $1,500. Most guys here probably spend more than that on oil for them over 100k miles.
Heck if the plugs all seize in which won't happen, you can buy a set of heads for like $300 on Ebay.
Cheap motors to fix, so just run them.
