Being in a rush to be able to get in the bank and pay off the loan for the lady so I could take the car home led me to make a big mistake, I checked the coolant res, but did not check the rad cap, well today I checked it and I seen a lot of brown mucky crap.

Now I am guessing in addition to the new coolant res I bought, I am going to have to get a new radiator.
And as much as I don;t want to admit it to myself, it is most likely going to need the LIM Gasket replaced, after removing the motor cover I can see a where a little oil has leaked out down around that area, I could have sworn that the 2005 and up SC'd motors all got the aluminum framed gaskets.
I really did not want to have to do this repair job again, while I can do it I am so tempted to shell out a few hundred in labor to not have to deal with it..
Oh what a day...
It is what I get for not taking my time and looking it all over though...


For the Radiator I am looking at this one. ACDELCO 21556 {#10324030, 15140506, 21472}
""CORE SIZE 30-5/16 X 14 6/16 X 9/16; Used on vehicles w/Bevel Washer at Transmission Oil Cooler; Quick Connect Fitting""

What the hell does bevel washer at trans oil cooler mean, I mean I get what a beveled washer is, but how do I see it without disconnecting the line?
It is the only AC Delco rad listed, so I am guessing it has to fit..

I hate to buy a new radiator, but considering how the cap looked I am guessing it really needs to be replaced.
One thing that worries me is how much of that crud is in other places..
If I get a shop to chemical flush it to clean it I am worried about leaks popping up..

Trying to look over the parts I would need to replace the radiator, and the LIM Gasket, I figure while I am at it I may as well replace the valve cover gaskets, and the SC Belt since it looks like it needs replacing.
I hope I do not have to remove a motor mount on this car to do that, I did no my 96' PA.

Hmmm, I see two belts listed, I thought I had only one belt, or is the supercharger belt separate?
When I looked at it the thing looked serpentine, and I did not see a second belt..
I am at like 265.00 with the radiator, thermostat, valve cover gaskets, sealants and thread lockers, and aluminum coolant elbow.
I hope doing this job on this 2006 Grand Prix GT is no worse than doing it on my 96'PA!

Wow, you just jumped in straight for the kill. I admit I would have started with just a basic coolant flush and taken it from there.

And to be honest, I have not seen any other recent GM FWD cars with an engine bay as generously laid out as the one in the 91-96 C-body. There is a TON of room in there.

I have not ordered the parts yet, I was considering flushing it a few times and see how clean I can get it.
And if that fails do the LIM job.
The reason I was considering the whole LIM job is that I can see where some oil has slowly leaked out all around the LIM gasket area..
And I am not sure how the coolant got in the condition it is in, considering how well I thought the car was taken care of.

Yeah my 96'PA had plenty of room to work with, with this 2006 Gran Prix GT the engine bay is a lot smaller, so it will be a knuckle buster..

Going to try to flush the radiator out several times till it runs out clean, going to even try some Zerex chemical stuff to help flush it out, if it cleans it so well the rad leaks, than so be it, I'll just get a new radiator.
I will go ahead and replace the coolant res since it is already on the way.
I'd going to stay with Dex, thought it over and reminded myself it is not the Dex, but irresponsible people that do not maintain their coolant system properly, they most likely let the res run dry, and air got into the system, then made the Dex more acidic.
That, and or some dumb *** mixed coolant types.
I'll change the thermostat while I am at it.
Once done I'm adding Zerex Dex Cool, and distilled water, and I'll keep an eye on coolant levels, and if they drop I'll check my oil level to see if it went up.
I am really hoping not to have to do the LIM Job, but if I do then I'll do it, that way I know it is done right.

Woh what a situation, gunk as in oil in rad?
If it is that bad..=eek!
I would want to do the U/L gaskets just to be sure I am not going to contaminate a new rad...This does not sound like what you were expecting.
Sorry to hear the news on the new 06..

I don't know it it was oil, it just seemed like gunky corroded Dex Cool that was probably in there since the car was made.
I thought it was almost impossible for oil to get in the coolant anyway, but not vice versa.
I'm not going to get the rad yet, I am going to flush it a few times, then see how it goes.
If coolant starts to disappear, then I'll commit to changing the LIM Gasket.

At least I got a few things done today.

Changed High and Low beams with some SYLVANIA SilverStar zXe High Performance Halogen Headlight Bulb'*.

Changed the fog lights to a tad brighter bulb, 898'* are factory bulbs, I went with GE NIGHTHAWK 893 Halogen Replacement Fog Light'*, they have like 180 or so more lumens, they won't last as long as the regular ones, but they are nice and bright!

Changed the Superchargers Oil, used some Genuine GM Fluid 12345982 Supercharger Oil, took like 7 ounces of it, the stuff was pretty brown, so I am happy I replaced it.

Changed the Air Filter to a K&N 33-2141-1 High Performance Replacement Air Filter.

Put in a 4Knines Rear Waterproof Non Slip Backing Seat Cover so my dogs don't ruin the leather when they ride with me, also so they don't slide into the floorboard, it hooks to the front headrests to form a hammock..

Now I just need to change my license plate screws, lady I bought the car from kept them, and my PA'* were getting rusty, so I got some BPARTS Stainless Steel License Plate Frame Screws Fasteners + Black Screw Caps.

Oh yeah, also got my K&N VF3000 Cabin Air Filter, still need to install it though.

I'll make sure no air is trapped in the system when I get done draining it, and I refill it.
Just made a solid investment, thanks to Gus for always mentioning this tool, it will be here soon.

William,

Same exact situation I found myself in with the 2005 SLE I bought last fall. Brought it home, only to find the radiator cap all full of gunk. Ordered a new radiator, but ended up flushing the radiator and sending the replacement back to rockauto. My cap (new) still gets crud on it, the flushing had minimal impact. I plan on just filtering the coolant every once in a while, using the mighty vac to pull it out effortlessly from the radiator.

I could not tell what caused the cooling system to get so gunked up. Either the LIM gasket or maybe an extended coolant leak at the elbow letting air into the system.

It sucked for me to do all the work, but it is done and the SLE is running that tank of a 3.8- all ended up well in the long run.

A few additional thoughts. I just went to the garage and opened the 2005 SLE radiator, cap had some gunk on it but not as much as before. Stuck my finger into and below the radiator neck and could feel a coating of dirty slime, this after a prestone super flush and two or three coolant transfusions.

Above is a bit of a downer- but in reality coolant appears to slowly be getting cleaner. I will do a few more transfusions when time allows. Not sure how much a radiator replacement would of changed things, unless I replaced the water pump, heater core, and all the coolant hoses. I am confident I am running coolant that is capable of doing its job in its current composition and that the cooling system is not degrading any of the engine or associated cooling components.

I did use DEX when I did the flush and transfusions, and I know DEX can do the job as I have used it exclusively in the 2001 SSEI with 240k miles and the coolant looks like brand new in the radiator. But, doing some research I did wonder if I should of gone with a universal coolant, not because it is universal but some research points out it is simply a much better designed coolant. Not to mention it is also less expensive and more readily available than DEX.