Spark Plugs.... 2000 GMC Sierra 1500 Z71 5.3lt.

I recently change my spark plugs on my 2000 GMC Sierra 1500 Z71. I Replaced them with ACDelco Platinum, same part number(41-952). A Couple of weeks after replacing them the truck started to run rough, so I pulled the plugs to see if something was wrong there. Turn out two spark plugs had cracked insulators between the terminal and the treaded portion. Since I still had the old ones, I threw those back in and went back to the parts store to get replacements. Turns out the part number had changed so the gave me new plugs with different numbers. I got home and compared them to the original plugs. Turn out the electrodes on the plugs with the "new" part number do not go into the engine as far as the original part number parts. I have been to several other parts dealers with the same results, none of them have the original part number plugs. So in the mean time the truck was running fine with the 6 new plugs and the two old plugs, until a couple of days ago. It started running rough again, so I again began to pull plugs. Two plugs were again cracked in the same region, and came from the _same_ two cylinders as the first two cylinders that had the cracked plugs.

Okay now to my questions:

1) Are the different electrode lengths a problem??

2) Is the fact that the all 4 of the cracked spark plugs came from the same

2 cylinders a sign of a more serious problem??

Thanks

Lou

Reply to
News Users
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"News Users" wrote

Yes, "you" are probably cracking the spark plugs. That's most likely the serious problem.

Ian

Reply to
shiden_kai

Well if I am the problem why is it that only the only 4 that have cracked have been on the same exact 2 cylinders. If it were randon them I would be more inclined to believe that it was me causeing the cracks.

Lou

Reply to
News Users

which cylinders are cracking? are they difficult to get at?

-Bret

Reply to
Bret Chase

The two cylinders are the drivers side closest to the firewall, and the passengers side closest to the radiator. Neither were very difficult to get at. The cracks are not very large. The look like hair line cracks, and can be seen by the charring caused be leaking spark.

Lou

Reply to
News Users

"News Users" wrote

So why did it start happening after "you" touched the spark plugs? Sounds like the only "constant" in this equation is "you". The old plugs were fine until you removed/installed them....and I suspect that the new plugs were fine until you installed them.

There is nothing about the particular cylinder that causes the ceramic to crack, unless I'm misreading your post and you are talking about the ceramic down at the electrode itself. From what you say, it appears that it's the ceramic above the threaded and hexed section. That part only breaks because of the "installer".

Ian

Reply to
shiden_kai

Well, I understand where you are coming from, but it would seem to me that if I had caused the problem then the engine would run poor right after I install them, not several weeks after the installation.

Reply to
News Users

Not if you produced a crack that got wrose over time, with all the hot cold cycles..

I was just checking out all of the plugs on my '99 5.3 and I cracked one just putting it back in.

Adair

Reply to
Adair Winter

Are you using a "spark plug socket" ?

Reply to
Scott

The crack itself will not necessarily be conductive, it usually takes a while for moisture, dirt, oil, etc. to accumulate in the crack before a misfire shows up.

This is noted as the ever popular "god damn it" when a routine tune-up comes back to haunt you and odds are that the parts delivery drone at some point dropped the set of sparkplugs during the delivery process. Bashed corners on the cardboard box and closed gaps are a sure clue...

Reply to
Neil Nelson

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