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.
