coolant ?

[04GTP]

i looked at my coolant today and found brown gunk in the overflow tank and in the radiator. should i do a flush rite away and check for anything else

[Bio248]

switch over to the green stuff after your flush. its the dexcool getting chunky on you.

[04GTP]

do i have to flush the motor too

[archemedes]

yes

[Sabrewings]

Instead of switching to the old green stuff, go with the universal yellow stuff by Prestone. GM chose to go away from the old green stuff for a reason, and Prestone's universal has the best qualities from both worlds without any negatives.

[GTPluv]

Thats what they did to mine.
My car never ran Hot, but I have noticed that it runs cooler now.

[SyntheticShield]

The reasons, as I understand it, for going away from the typical green coolant was for water pump life/longevity. However, Ive never had a pump go bad that I could ever tell because of coolant. Ive only had to replace one because it did actually go bad and that was in my previous grand prix.

That said, Dex-Cool has been the only coolant I have ever seen that gunked up the way it does. After it cost me my radiator, I switched to the green all makes and models coolant and never had an issue.

After I pulled out the engine and got my LIM off, there was STILL some of that Dex-crap stuff in the coolant passages in the heads. Not much but it was there nonetheless. Ive said it before and I'll say it again, Dex-Cool will never touch another car I own.

[Sabrewings]

For the most part, it's not Dex's fault. A properly maintained coolant system will not have any problems with Dexcool. The problem is when air enters the system or slightly failing gaskets (internal, so you'd never know). Then Dexcool reacts adversely to the contaminants.

Yes, there's a Dex suit out there. But, if Dex was the problem, why aren't all of GM's cars involved? Its only the ones with gasket issues like ours...

[archemedes]

also if dex was the real cause why is it gm being sued and not prestone (who makes and markets the stuff)

[SyntheticShield]

Well, I mean no offense, it is Dex-Cools fault or at least its formulation. In all the years I have owned cars and some of the early ones were not exceptionally well maintained, I NEVER ONCE had the coolant gum up and deposit the crap that Dex-Cool did in my radiator and I have yet to see a green coolant ethylene glycol coolant do the same.

There is just no way you can get all the air out of a coolant system. Sure, you can get a lot of it out if not most of it but not all of it and to produce a coolant with that sensitivity to air, well they just should have known better.

The reason Prestone isnt being sued is that they just manufacturer it to GM's specifications. Its licensed from GM I believe. GM controls the formulation, licensing and so on. So while Prestone is a manufacturer of Dex-Cool they have to get that license from GM and make it to their specificatoins.

The reason, I believe, not all GM cars are involved is due to in part, radiator design. And this is just a theory as I have not went around and looked at every vehicle GM makes. But the GP radiator design is set up in such a way that the fill neck is slightly lower than the upper radiator hose connection, which is why there is air trapped and you have to bleed the system among other reasons. Not all GM vehicles have the air bleeder port we do on the GP at least.

I didnt notice this until I installed my coolant filter and realized that when I filled up the coolant through the filter (spliced into the upper radiator hose) I did not have to bleed the system. I was able to fill it up to such a point that there was very little air in the radiator. Of course I still ran it up to temperature and would work the bleeder valve but it always flowed coolant from the start.

So a few posts here by others and it dawned on me, or at least I believed I understood what was going on. So that has been the theory I have been working from. But again, whether it be a Dex-Cool issue, its formulation, whatever the simple fact is all was well until GM went to that coolant. I have looked far and wide to find a vehicle that still used green coolant and exhibited the same sludge build up or Dex Sand deposits in the radiator and to date I have not found one.

[Sabrewings]

The main reason Dex does it in these cars is because of the factory stop leak pellets GM put in to try and cure their failing gasket problems. Not Dexcool's fault, and the reason not all GM cars have the problem.

[SyntheticShield]

What I dug out of my radiator was not the pellets. That had in fact cross my mind at first. What my coolant filter filtered out was not the pellets either. The gelling/gunk that builds up is not from the pellets either. Im not discounting what you are saying, but I am saying that Dex-Cool is entirely too sensitive to air to be used in a cooling system.

What I find most telling is that Toyota, Ford, etc all use their own long life coolants and have not had the same issue. And they only in the last few years switched to those whereas Dex-Cool has been around since what, early to mid 90's or so, maybe earlier. My '89 GP had a bleeder valve on it but used the green coolant and never had a problem with gel build up ever and it had almost 200k on it and still running when I sold it.

Likewise Ive seen examples of GM products that did not require bleeding of the system that ran Dex-Cool and did not have the gel build up issue which seemed to support the main problem being the sensitivity to air coupled with radiator design. I used to take notes on all the GM vehicles I serviced with regards to their use of Dex-Cool, bleeder system or not, etc. and whether or not they had any type of gel build up or not and the pattern became pretty clear after a while.

That all said, I am eagar to see what comes of this suit that has been filed and see what conclusions they draw. Obviously GM is not going to admit to anything, after all, they did pin the GP fire issue on small drops of oil getting on the exhaust manifold.

My personal opinion is that the failing gaskets just exasperated the issue not really started it. But that is just my personal opinion and I dont mean it as an attack or anything of the sort on you, just offering my opinion, perspective and observations.

[Sabrewings]

I don't think I'll ever blame Dexcool directly. But, at the same time, I don't put it back in either. I haven't flushed yet, but when I did my gaskets most of it came out and I put back in a couple gallons of the yellow stuff, and I'm happier for it.