Hey guys,

I recently bought a 04 GXP and am looking to do an antifreeze flush. I am going to stick with Dexcool, bought all the supplies, and realized there is no radiator cap under the hood? I know where the drain petcock is I am just skeptical of refilling the coolant system from the overflow tank. What is the proper process for this? I've done this a handful of times on other cars but don't want to cause any other problems.

What is the total capacity of the coolant system as well?

Thanks in advance.

That's how you do it. Many GM vehicles are like that.

10 quarts.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

Sounds good, now I can take care of this tomorrow.

Thanks!

What's everyone's thoughts here on the dexcool?
I know some flush and get away from it. Any reason to get rid of the dexcool?
I'm under the belief to keep it but keep it clean. Changing can be a real problem if every last ounce isn't removed first.

_________________
01 Bonneville SLE

I'm fine with it.

It's a never ending debate on this topic. But as long as you're on top of maintenance it shouldn't be an issue.

Most Dexcool issues stemmed from other mechanical issues that preempted the coolant issue.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

I got rid of the Dexcool in all my GM vehicles I have owned over the years. Given all the issues some folks have had, I just didn't want to take a chance.

I use Prestone "mixes with any antifreeze" in my GMs and Fords. No issues what so ever.

This is an excellent video. https://www.youtube.com/watch?v=Ffpe8aVvb2c

I'm no mechanic, but "DITTO", minus Fords as we only drive GM. - BC

EDIT:

for me, distilled water is all I use, regardless of the collant, even in the windshield washer tank. - BC

_________________
In Memory of Brad - 1/21/1977 .. 10/23/2013 ...... Aaron - 1977 .. 2017 .....
2017 Hyundai Santa Fe Sport ..... 1992 Bonneville SSE 1SB 170 HP L27 4T60E retired/sold to MattStrike ..... 2005 Bonneville SE 1SC 205 HP L36 4T65E - retired/salvage yard ..... PBCF user 2321

I am along these lines, but my understanding is coolant contamination (even by air) was the biggest concern, that causes it to turn acidic. If you go with it, distilled water is a must.

If it was my vehicle, I would switch it with "mixes with any" antifreeze at the next time the coolant was drained, because my maintenance habits aren't that great, and I don't want it nagging at the back of my mind. I also don't want to have to worry about what some oil change place puts in it as a 'courtesy'.

_________________
~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place

Well I've learned long ago not to trust anyone but myself when it comes to changing my oil even.
With the exception of a local shop I take my Pete to for stuff over my head. Even on that I do my own servicing tho and that's no easy task when you're talking 12+ gallons of oil and grease fittings up the a$$.
I'd like to change to regular antifreeze when I really think about it but I need to be 100% convinced I was getting every last drop of Dex out. That bothers me a little more than keeping it does I guess.

_________________
01 Bonneville SLE

First thing. When swapping fluids, it needs to be complete. You aren't to "mix" Dexcool with others, especially if you convert back to old school Ethylene-Glycol. It needs to be completely evacuated from the engine cooling system as well as the heater core, any heater valves, and all that associated plumbing. A typical drain down, flush, and dry won't necessarily get all this. I always recommend when converting, having an actual machine purge out the entire system.

Second, A properly operating cooling system is dependent on being able to pressurize and purge air. IF it is properly pressurized, air is purged, the system is effectively closed. It will then run fine no matter what you put in it. Be it water or the best coolant money can buy.

Once air is introduced, that is where the issue comes in. And we all know 3800's are prone to UIM and LIM gasket issues. Now we can get into the classic "what came first... The chicken or the egg..." However, if Dexcool is/was so toxic to gaskets and seals when air is present, that it eats UIM/LIM gaskets... Wouldn't it also eat head gaskets? Wouldn't it eat up water pump seals and gaskets? What about inter-cooling systems (GM uses Dexcool on their supercharged V8's)? What about the innards of the radiator? Or even any hose that the coolant touches? Be that the normal coolant hoses or heater hoses or inter-cooler hoses, etc, etc...

Since that doesn't happen (I don't recall EVER having to replace head gaskets on ANY GM vehicle due to Dexcool), and it seems for the most part that the issue seems to be majority isolated to 3800 engines as N*'s, GenIII and IV V8's (I'm excluding the Gen V's as they're too new yet), and other GM engines don't seem to be mass affected by Dexcool woes... That it isn't the fluid!!! It's the bad UIM and LIM gaskets... If you put old school Ethylene-Glycol or any other type of coolant (Ford/Chrysler G-05, or the Prestone hybrid mixes), your results would be the same over time if there was an air leak caused by a bad seal/gasket.

Now add to this, the fact that GM sells these vehicles on the fact that you have lifetime coolant, lifetime spark plugs, lifetime transmission fluids, lifetime whatevers under these hoods, most people never open the hood, much less perform necessary preventative maintenance that could've prevented the problem at the first sign to begin with, that this problem exacerbates itself. Most here have as much mileage on their hood release mechanisms as they do on the car itself. Which means that they're also on the lookout for any issues. I for one check my coolant daily on all of mine.

I guess my whole point is a properly sealed and pressurized system won't have any issues regardless of what fluid you're using. If it ISN'T properly sealed and pressurized, it doesn't matter what fluid you're using, you're going to eventually have a problem. If you're doing your proper preventative maintenance on the vehicle and this gets checked frequently and any issues addressed, you'll be fine regardless of what fluid you use (Dexcool included).

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck