04 Grand Prix GT 3.8L Intake Manifold Question

In cleaning up the Intake Manifold I ran into something that has me wondering if I have a problem or not.

When I took the manifold off, one of the Water Passages on the Rear Head, was packed with some hard powdery gunk. It was not one of the passages where the water crosses over the intake to the other head. I cleaned the gunk out of the head no problem.

I took a couple of pictures when I was taking it apart the one of the head on the car didn't come out the greatest. There also is one of the intake itself with the gasket still on it.

Then when I was cleaning up the intake it appears that there is a pocket that looks like either a casting imperfection or corrosion.

I took a couple more pictures one close up and then another with the new gasket propped up against the intake.

My question is this a problem, am I going to have a problem trying to seal this passage, does the intake need to be replaced or is there a repair that could be done?

Little confused as how to proceed, not ever seen anything like this before.

Can you post some pic? Did you have cooling problems?
Does your temp gauge goes over half when car sitting on red light or when idling for long time?

That my friend is what you call corrosion. I dont need to see a picture because I know what it is. It is from not changing the Dexcool at the proper intervals, or from the dexcool mixing with air--as in low coolant levels, or dexcool not mixed to the proper ratio. Dexcool will turn acidic if you dont baby it, treat it like blood basically. Gotta change it sooner than MFG suggests and if it gets low, flush it and start again.

Dex cool muches on everything when not services properly. Its an OAT (organic acid technology). It works great, but you have to baby it.

I think you just have to make sure it will seal correctly. Make sure its still has enough flattness to make a seal. use a straight edge and feeler gauge. When it doubt, take it to a machine shop, maybe they can weld it up and plane it down.
Well I guess thats if you have a metal intake, 3.8's are plastic right? Might just hvae to replace if its not straight.

That my friend is what you call corrosion. I dont need to see a picture because I know what it is. It is from not changing the Dexcool at the proper intervals, or from the dexcool mixing with air--as in low coolant levels, or dexcool not mixed to the proper ratio. Dexcool will turn acidic if you dont baby it, treat it like blood basically. Gotta change it sooner than MFG suggests and if it gets low, flush it and start again.

Dex cool muches on everything when not services properly. Its an OAT (organic acid technology). It works great, but you have to baby it.

I think you just have to make sure it will seal correctly. Make sure its still has enough flattness to make a seal. use a straight edge and feeler gauge. When it doubt, take it to a machine shop, maybe they can weld it up and plane it down.
Well I guess thats if you have a metal intake, 3.8's are plastic right? Might just hvae to replace if its not straight.

2004 should be with metal intake.
series 3 is metal intake.

Actually the car had no over heating issues. It was just loosing coolant after long drives.
Car runs great.