noise in 3800sc 2004 gtp lifter?

[fam_mechanic]

I have a 2004 gtp with the 3800 super charged v6. last month I changed the plugs after the wife said it was running rough. Number 2 plug gap was smashed shut.After finishing the tune up I also noticed it was low on coolant,(no dought a lower intake gasket).So I went out and changed the oil. she drove the car once more then I drove it once,no more then 30 miles tops.
Basically I got a tapping noise now. after using the old broom stick, I noticed the noise is on top. a little louder over the valve covers on the (odd) side.I dont hear it down in the pan however.
Is it possible that i had a lifter drop? ,or wash out?
Has this been herd of before?
thanks ya'll, just want to know what im getting into this weekend

[GTP Dad]

It is possible that you have some internal engine damage due to the fact that the plug was bent shut indicating that either the piston hit it or something entered the combustion chamber. As for the lifter it is possible that the lifter has collapsed due to water being in the oil. If the lower intake gasket is bad I would pull the manifold and replace the gasket and investigate further.

One question, is this engine stock or modded?

[fam_mechanic]

all stock 94,000 miles. car ran like a champ after the plugs were changed. I wondered if it maybe was part of the gasket that ran thru the engine.?Car is only driven at the most 20 miles a week. Plan on tearing into it this next weekend. I did however pull the #2 plug just to check and its still ok.Clean but i swear there was a green tint to it. coolant went to green when i got the car 2 years ago.No sludge,and water working good. nice to get a second opion on the lifter, I was pretty sure thats where my noise is,but wanted a second opion. thanks again

[GTP Dad]

I would run a compression check on this engine to see if there may be a head gasket problem or a burnt or bent valve. It is highly unusual for the SC engine to have intake manifold gasket issues unlike the NA engine. If the plug has a green tint you could have other issues like a cracked head that is causing your problems. I hope not but it is possible.

[tblake]

Are you sure the 3800SC doesnt have as many LIM issues as the 3800NA Lynn?

[GTP Dad]

It is very seldom that the SC engine has issues with the lower intake manifold gaskets. The NA engine especially the older ones did not have the quality gaskets that the SC engines did. Due to the pressurization of the engines the gaskets were a different type and didn't experience the same problems.

[BNaylor]

Keep in mind the '04 and up Grand Prixs with the SIII 3800 engines both L32 (SC) and L26 (NA) have the revised aluminum framed LIM gaskets but I've seen anecdotal data they do fail depending on the mileage and region so I would not rule out the LIM gaskets. On the prior generation L67 SII 3800 although not as common as the L36 engines the LIM gaskets do fail. I've replaced mine in my GTP. L67 LIM gasket issues is fairly common in the hotter desert Southwest and Western U.S. Typical symptoms are unexplained coolant loss and having to add coolant periodically or coolant contamination in the engine and seeing steam come out the oil filler cap.

What grade of fuel does the OP use? It sure sounds like detonation and knock retard on the spark plug issue and possible internal engine damage.