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.

I think I looked at your another one of your threads. That is dexcool as stated before, Take off the gasket and throw it across the yard, then inspect the flat mating surfaces. Im pretty sure it can be cleaned up. check with a straight edge though. Buy an aluminum Lower intake manifold gasket. It will never corrode like that plastic nylon those idiots at GM engineered. Thats why they had a class action lawsuit because of dexcool eating their nylon LIMs

I think I looked at your another one of your threads. That is dexcool as stated before, Take off the gasket and throw it across the yard, then inspect the flat mating surfaces. Im pretty sure it can be cleaned up. check with a straight edge though. Buy an aluminum Lower intake manifold gasket. It will never corrode like that plastic nylon those idiots at GM engineered. Thats why they had a class action lawsuit because of dexcool eating their nylon LIMs

2004 Grand Prix should be aluminum intake.

I think I looked at your another one of your threads. That is dexcool as stated before, Take off the gasket and throw it across the yard, then inspect the flat mating surfaces. Im pretty sure it can be cleaned up. check with a straight edge though. Buy an aluminum Lower intake manifold gasket. It will never corrode like that plastic nylon those idiots at GM engineered. Thats why they had a class action lawsuit because of dexcool eating their nylon LIMs

Can the cleaning be done with coolant flush or something like that but stronger? I have some kinda heating problem and after saw this, it might be a problem with mine car too.

Don't know why the forum created two posts, I only entered one. For some reasons all the pictures don't show up either. Anyway, I thought it was corrosion, but was hoping for something else.

Going to check out your machine shop suggestion and search the net for any other repairs. Someone already suggested JB Weld, but I am not sure that it would hold up under the conditions.

Already bought the Aluminum Gasket set, yep the Plastic carrier one is junk for sure.

Was also planning on switching to the gold old green antifreeze as I had heard about all the Dexcool issues. First time I have experienced it myself.

Thanks for your help.

Just trying to get this Car back on the road for my son.
He saved up enough money to buy this car, which is very nice by the way only to have issues like this with it so soon.

Yes in this car both the Plenum and Lower Intake are Aluminum Castings.

JB weld has been done, but its one of those things where it might work, but probably wont work for long. just get it spot welded and planed by a machine shop, if it even needs it.

Was also planning on switching to the gold old green antifreeze as I had heard about all the Dexcool issues. First time I have experienced it myself.

I've got a 99 GTP with 196k miles. Have always used Prestone Dex-Cool and experience some sludge sometimes, such as at the cap/neck of radiator. I simply wipe it up and carry on. No major problems. Just flushed with Prestone flush kit and Super Flush and refilled with Prestone Dex-Cool. The low coolant indicator does light up sometimes when there is sufficient coolant; replaced the sensor once, but still had the problem. I've read that the sensor has problems with the Prestone, so some folks stick with GM.

I considered changing to the "yellow" OAT coolant/antifreeze. But after researching it, decided to stick with Dex-Cool. I'm not sure the yellow OAT won't have the same sludge issues. There are several threads discussing coolant preferences and changing coolants...I recommend that you review them to make an informed decision. Seems like coolant preference is a religious issue, but some of the most prolific, knowledgeable, and helpful posters "recommend" sticking with Dex-Cool. If you do change, you gotta do a thorough flush to get out all the old stuff.

I would say that 95% of people on other Grand Prix forums recommend that Dex cool is crap and to switch to the green stuff. I switched a few years back and haven't thought twice about it.

If there is any blockages through the cooling system from dex-cool can I clean it with flush or some other special products?