John, Boosty, Don: Seems like I am outnumbered here, but I gotta ask again, are you sure this is not just a Prestone brand of Dex? As I understand it, there is a significant difference in the formulation of Dex. I have read that it is based on organic acid technology. And although it was developed as a long-life, low maintenance product, well-documented problems have occurred. After five years, Dex can begin to break down to form acidic components that attack plastic gaskets. Some have reported that if the cooling system has a leak and the Dex is exposed to oxygen, that the breakdown can occur earlier. If Dex is mixed with the old, green coolant, a sludge-like precipitate forms that can block cooling passages including heater cores and radiators.

Some BC members who change and flush their coolant within the recommended five year period have reported no trouble at all with Dex, while others have claimed problems within months. Although many have apparently had good luck with it, my experience in tearing down engines that have used Dex have shown me that Dex has an evil side. Until Dex, I had never seen heavy, brown, crumbly precipitates in cooling passages, or slimy brown coolant. My experience and reading those of others has led me to recommend against its use.

The question is: why would we recommend that anyone use Dex when there is a better product available with NO reports of any problems? Prestone Dex is orange, and as far as I can see, it does not say that it mixes with all types and colors, and that is close enough to Dex for me to say: don't use it.

[edit] I am not recommending that folks spend big $ on pre-mixed coolant BTW, I use Wal Mart mixes with any color in mine.

see above

Uh..yeah..you posted twice in a row...lol

Bill... 1 year and no coagulation. I haven't sent a sample of dex and PLL out to lab...yet though. We could hash this out for another 5 pages.. or accept that coagulation is an expected Dexcool property and it doesn't occur with the LL. As well I think Don has pulled gaskets and found good results.

More research may be needed...

Usually takes longer than 5 years for Dex to cause problems.

Agreed

No way Jose! Remember the CorvetteCrazy pics after only 1 year? Dex is a deadly liquid... it coagulates in an overflow within a month or two.

Ok..Hop to it...lol :P

OK , I hopped to it. My reading of the Prestone description for orange Prestone extended life is that it is Prestone'* formulation for Dex. Here is the link: http://www.prestone.com/carcare/faq.php Just like Dex, they do not recommend anywhere that orange Prestone can be mixed with all colors and types of coolant:

Q. What about topping off with PrestoneŽ Heavy Duty Extended Life Antifreeze/Coolant?
A. Topping off with conventional silicated antifreeze/coolant in a system protected with Extended Life antifreeze/coolant is not recommended. More is said, but that'* what they said first.

OK, won't mix with the old green stuff, just like Dex

PrestoneŽ Extended Life 5/150 Antifreeze/Coolant has been approved by General Motors under their DEX-COOLŽ specifications and is compatible with other DEX-COOLŽ approved coolants.

But OK to mix with the orange stuff, Dex. See, you guys read that it is compatible, and infer that it is NOT Dex. I read that it IS Dex

Perhaps more research is needed, but I say this stuff is just Prestone Dex. No different than Havoline Dex or any other nasty old Dex.

Until someone can demonstrate that Prestone'* orange formulation is different from those other bad orange Dex formulations, why would you recommend it? Especially when there are widely available, inexpensive, non - Dex alternatives.

Bill...I'm gonna send you some coagulation from Dex... I swear.

Please read what they wrote, not read into it the way you wish to view it. That'* not a knock..but it seems that you are looking for one answer and one answer only. Don't twist their words and jab them into someones back....that'* what ex gf'* do

The top off answer says don't top off LL coolant with conventional silicate stuff. Green and orange don't make any pretty colors... All this says to me is don't mix standard green with orange LL. I already knew that. Maybe the further information you didn't post would answer if you can top off the LL with LL

OK, lets look at this from a different angle. You have flushed your cooling system. You have a choice between Orange Prestone extended life that will mix with Dex compatibles only, and Yellow Prestone extended life that will mix with anything. What advantage does the orange stuff give you?

Nope, it doesn't read that way.

The AnyColor will mix with the Prestone Orange Dex Compat.

I'm really not trying to be difficult..merely trying to get this straightened out.

I thought the big problem with the Dex was lack of maintenance and letting it get low. I also thought that the PLL was the same as Dex. I read on this forum ;


"I like the Dex Cool coolant but its sooo important that its kept full at all times, as well as not mixed with a noncompatible coolant, it just creates a mess...
"I will continue to use Dex In my 95... I have had no issues... I know people at 150,000-200,000 on dex and they to have had not 1 single issue... " well over 7 years of ownership, and I have not had 1 single issue with dex cool.".. That was JR's3800 that posted that on this site,


then I read later that that he posted "And BTW, I got 4 years out of my water pump the first go around, 1 year on the replacement GM unit... 4 Years on the Unit i installed... And have almost 2 years on the last one... My 91 uses the exact same pump and is almost at 6 years with Green coolant that is way overdue for a flush and refill... Some water pumps last longer others dont "
Did Jr's3800 switch to the green ? If so why if the Dex worked so well ?

Then I see where WillWren posted that Dex goes bad in as little as 10,000 miles,

man im more confused that a one legged man at a sock hop !

I am going to put in the PLL I guess , seems as though NOONE really knows as everyones opinions and what they use is changing.. I have read posts that go back and forth so is the Dex the devil or don't we really know. Would we all be better with the green, I have seen Jr'* post that he has seen gaskets go out with that also..

Decisions,decisions