Im just flipping this out for your guys input I have a friend who is a very good 30+ year mechanic, working at various locations including a stint at a GM dealer. In a casual conversation the other day, showing him my old LIM gaskets and talking about the job, he observed a bottle of yellow, any color, any make, any car antifreeze sitting there. He says, you didn't put that in there did you? I said I sure did. Because I had heard that Dexcool was bad news. He said that the any color any make yellow was a top off only and not to be used as a stand alone. He said there are plenty of documented cases of corrosion to radiators, heater cores and other damage that was supposed to be caused by this kind of antifreeze.

He went on to say that the newer generation of Dexcool was the proper stuff I should use and to change it every two years.

Im quite surprised by this.

And let me reitrerate, this guy is a very good mechanic who has been around the block, seen lots of stuff and is still currently employed at a full tiime independent shop. And he has nothing to gain financially or personally by telling me this. He is convinced that its bad stuff.

Any body else hear anything like this or of a newer generation of Dexcool that is improved?

Hmm, that'* what I used after I swapped enges...

My grandpa took is 98 Bonneville SE to the dealer to have the system flushed. I told him about the dex cool. He went and asked the dealer. He said that the problem has been corrected because the modified the Dex-Cool formula. Oh BTW, on his car, 104,000 and no LIM problems.

Anybody?

It'* hard to say whether or not the "mix with any color" coolant is corrosive as your friend proclaims. The mix with any color coolant has been out long enough for anyone to run any long term tests. Dex has and has proven its inability to preserve gaskets.

I guess time will tell if the alternative to Dex is any good....

The same could be said of the "new and improved" Dexcool. We won't really know until it'* been tested over time.

For the time being, I'm not touching Dex. It has proven itself time and time again that'* not a reliable coolant.

Moving this to General Chat since it'* not a mechanical post.

First of all he'* WRONG to say Prestone all makes is a top off fluid.
The original Dex was made by Texaco. GM Engineers switch to Prestone Dex in the late 90'*.
I have never had anything but good results with Prestone products and currently run the Yellow all makes in two of my cars.

http://www.zillamotorsports.com/DEX

That page also addresses the re-formulation, and covers everything else GM won't tell you.

While in the auto parts store the other day, I saw a jug of Havoline Dex Cool. Now I was in a bit of a rush and had looked over the label front/back. I did not see any listing for the percentage of ingredients in this "new" formula. In contrast, all the Prestone products clearly list what is inside.

Here is the Prestone fill instructions for the All / Makes Models extended life coolant.
http://www.prestone.com/carcare/howto.php

It makes absolutely no sense whatsoever that they would make an antifreeze that would be for "top off" only. What would be the point? Even if they did, don't you think they would say so on the container?