So my car Misfires at WOT around 6200 RPM. Pulled the Coil pack and spark plug to find that the plug was rusted but no water was present. Replaced the plugs and pulled cylinder one a week later to check and lots of water. Was there ever a resolution to the TSB about this? I searched and could only find the initial release but no guidance on what is causing it.

 

I'm guessing, but isn't it missing an o-ring gasket? Pull one of the other coils to verify.

 

All the coils are the same.

 

Confusing thread name. "Water intrusion Cylinder 1".

Since there is no water intrusion into the actual cylinder, I guess you just mean into the sparkplug well.
My question is, where is the water coming from ?

 

That is the question, where is the water coming from? All of the Coil packs are the same. IE, I don't believe this one is missing a o-ring. Going to replace the camshaft cover gaskets tomorrow. Hopefully this fixes it. Yes, I could have titled better I guess.

 

What was the TSB you mentioned? Do you have any details on it?
*Update - found it in this thread - https://www.chevyhhr.net/forums/prob...njector-18749/
*further Update - in thread - https://www.chevyhhr.net/forums/prob...e-codes-27512/
"The engineering TSB was closed with no clear cut solution as to why the codes were being set. They recommended that the dealer follow normal diagnostic procedures."

If it was full of oil, then yeah, the valve cover gasket would be suspect. But not if it was water. There was another member that had a similar problem if memory serves me right - will see if I can find it.
*Update - could not find any resolution to the few people that have had the same issue.

Suggestion - use a liberal amount of dielectric or silicone grease on the cap where the coil fits over the lip to the plug well.

 

Drove today with no misfire. Nice and dry. lol Raining now going to check in the morning to see if there is water present. My thinking with the valve cover gasket is that where the camshaft solenoid sits is the lowest point and where water would pool if it was on the engine. this happens to be right next to the problem spark plug well. I didnt get to change the gasket today though. oh well next weekend I guess.

 

It looks like condensation was pooling in the plug well, but not terribly likely.

Are you the sole driver of your HHR, or does someone else drive it on occasion?

If it's the latter, they may have plowed through some high water in the not too distant past.

 

Since the residue is orange and DexCool is orange I am thinking head gasket.

Was the outside of the spark plug orange also? When coolant leaks into the combustion chamber it tends to blow through the plugs between the ceramic insulator and the metal part.

Or, if you are one of the people who "steam" cleans under the hood, that could be it too.

Or, that's right next to the washer reservoir. Sloppy filling might do it.

 

It does appear to be an O ring is missing in the groove just under the coil , but if they are all the same why just #1 is wet?
I recommend a compression test and double check your coolant level