: Dex-cool controversy



VinnyT
08-12-05, 08:30 AM
I want to change my fluid, but hear so many horror stories regarding Dex-cool. One is that it corrodes the aluminum parts in the engine. What is the real story? Does anyone have an insider at GM that concurs with these horror stories? I want to change the fluid this weekend, but I am divided on using Dex-cool or the green stuff. Thanks for your help. V.

EcSTSatic
08-12-05, 08:38 AM
Do some searching. We have a GM engineer on the forum that says to use Dex-Cool in the N*. If you've already used the green stuff, you may have to stick with it.
Search, for enlightenment http://cadillacforums.com/forums/images/smilies/cloud9.gif

VinnyT
08-12-05, 08:44 AM
I have searched here and found that we should stick with Dex. However, doing a Google search on Dex reveals nothing but negative info regarding this stuff. Overheating probs, corrosion, etc. I guess it all depends on the vehicle and the metalurgy of the engine? Argh, I just don't know.

Katshot
08-12-05, 08:51 AM
I used Dex-Cool for several years in a fleet situation and never had a problem with it. Years later, after getting out of the business, I did have some issues with it in my personal car ('95 Fleetwood). At that time, a freind of mine (who owns a repair shop specializing in heating & A/C and is an expert with over 25 years in the field) related many horror stories concerning Dex-Cool. Enough so, that I now question whether it is the best choice. Regardless of anyone's opinion, if your car has EVER had anything other than Dex-Cool in it (no matter how small amount), using Dex-Cool is of little benefit to you. According to GM, once you contaminate the system (with even the smallest amount of standard coolant), your cooling system must be regarded as NOT able to handle the extended service life advertized for Dex-Cool, and you need to revert to the standard 30,000 mile drain intervals.

Ranger
08-12-05, 01:00 PM
Dex works great. Do not use it full strength though. The problems you are hearing about is with cast iron Chevy engines. As I understand the problem, they are not maintaned and the coolant gets low. Dex, unlike the green silicated coolant does not plate the water jacket with silicates, so it MUST be kept full. When it gets low, rust starts to form. As the coolant sloshes through the system it washes the rust particals thought the sytem where they collect in a low point. Then people blame Dex for the problem. I have 104K on mine and have had no problems whatsoever. Neither have most others on this site. That would seem to bear out the above scenario.

EcSTSatic
08-12-05, 01:36 PM
I think part of the problem is the electrical potential created between two dis-similar metals. e.g. cast iron and aluminum (block and heads). A current is created due the difference in electrons and the charge removes molecules from one metal or the other.
This shouldn't happen in an all-aluminum engine like the N*. A proper coolant mix helps to eliminate this charge in situations where it could occur. Problems hapen when the coolant is contaminated, gets old or not mixed right.

Katshot
08-15-05, 08:27 AM
I think part of the problem is the electrical potential created between two dis-similar metals. e.g. cast iron and aluminum (block and heads). A current is created due the difference in electrons and the charge removes molecules from one metal or the other.
This shouldn't happen in an all-aluminum engine like the N*. A proper coolant mix helps to eliminate this charge in situations where it could occur. Problems hapen when the coolant is contaminated, gets old or not mixed right.

There's dissimilar metal corrosion in any aluminum engine. There's always going to be some ferrous metals in the engine. It's virtually impossible to 100% seperate all the dissimilar metals so there's always going to be an issue with this process. The "proper" mix of coolant helps to minimize the destruction caused but it will never eliminate it.

EcSTSatic
08-16-05, 12:04 PM
There's dissimilar metal corrosion in any aluminum engine. There's always going to be some ferrous metals in the engine. It's virtually impossible to 100% seperate all the dissimilar metals so there's always going to be an issue with this process. The "proper" mix of coolant helps to minimize the destruction caused but it will never eliminate it.

I was speaking mainly of the head/block interface but I stand corrected. The main point is that DexCool isn't your problem.