austinseanchris

So I just bought this 96 Corvette about a month ago, pulled off my coolant reservoir cap the other week and filled it up to the full mark and noticed today when I was under the hood that it said to use GM Dex-Cool coolant only. Well guess what? Yep, I filled with the traditional Prestone yellow antifreeze and have been driving it. Do I need to drain ASAP and go back to Dex Cool? Is it ok to run like it is or do I need to drain and fill with all Prestone? I've heard a lot of negative things about Dex-Cool, but dont know a lot about it unfortunately. I heard when the two get mixed, they create a sludge? Anyways, can you guys tell me what I should do? And I'm assuming that if you run straight prestone, that it's ok to run a bottle of Water Wetter in there as well? For what its worth, a bottle of that has been run through the system as well...thanks for the help in advance...What about if recommended to run Dex Cool only...can you run a bottle of water wetter in it? My fingers are crossed...

mrvette

Drain the system, I don't trust mixing ANY coolants in ANY car, especially with unknown history....flush completely with water till it runs clean....

dump a fresh gallon of 100% ethelyn glycol /GREEN in the rad, fill with water to the top....

I would have nothing to do with any other coolant/antifreeze than the good old GREEN e/Glycol....

AzMotorhead

Pull your knock sensors out & drain it all. refill with green coolant/water.
If you don't have to worry about winter freeze-ups I'd run 30% glycol mixture. Water transfers heat better but has no anti corrosive or lube properties.

zwede

Which prestone? The long-life version is compatible with dex-cool. I've used it in a variety of cars and never had any problems.

austinseanchris

Well its just the plain old prestone original yellow antifreeze. Its not the long life dex-cool...So everyone on here agrees that even though it calls for dex-cool only, to swap out and run original prestone, correct?

noonie

Now matter which way you decide, just change it out yearly, cheap insurance, don't believe the long life story. That's where most problems arise.

austinseanchris

Well I do that as it is, but what I'm wanting to verify as that these can/can't be mixed or which one I should use?

zwede

Traditional anti-freeze cannot be mixed with dex-cool. You need to flush it.

Personally I'd go with the Prestone long-life. I've had excellent luck with it in a variety of cars and I do go 4-5 years between changes. I've never seen any signs of corrosion or sludge even after 5 years.

GM does not recommend traditional anti-freeze in the new motors as they say it decreases the life of the water pump.

austinseanchris

So zwede, with that stated, since its a newer motor, should I run the dex-cool or the traditional anti-freeze?

zwede

I use the prestone long-life in new motors also. The traditional stuff starts eating aluminum unless you change it every 2 years. With the new stuff I see no signs of corrosion of the aluminum even after 5 years.

Dex-cool got some bad press as it is sensitive to air in the system. It works well if you get any trace of air out, but forms sludge when you don't.

I would not run traditional anti-freeze in a Gen II LT1. The water pump was designed for new style antifreeze. I forget what it was exactly they got rid of in the new anti-freeze... silicates? Anyway, by removing whatever it was they could change to different seals and increase the life span of the pumps.

capevettes

In my newer Corvettes that came from the factory equipped with Dex-Cool, that is what I run. In my older cars I run the good old green stuff mixed 50/50 with distilled water.
If you mix Dex-Cool with a regular ethelyn glycol based anti-freeze you will end up with a gelatin like mess inside your motor and cooling system. I would purge your entire system and re-fill with Dex-Cool.

7T1vette

The manufacturer recommends using Dex-Cool. Dex-Cool is designed to work well with aluminum components. I'd suggest you use what was intended to be in your cooling system/engine.

mrvette

Dex appeared and some large amount of cars had brand new warrenty issues due to corrosion/reactions/whatEVER....point being, why FIX something that's not BROKE??

E Gly works well for some decades now....in aluminum, steel, iron, brass, got any other metals we adding to the list??

my Mom's '63 Olds F 85 4 dr sedan, sat in the garage for some 25 years with that steel liner'd cyl wall 215 cu inch V8....and nothing missed a beat upon startup for a month, then selling the car....

427Hotrod

Here's some excerpts from presentations I use to provide some basic understanding of the coolants.

Conventional Coolants

Conventional antifreeze uses inorganic materials such as nitrites, silicates, phosphates and borates to control corrosion, but as these materials coat to provide the protection they offer, two things happen. First, they deplete or are "used up" and need to be replenished. This adds more material to the liquid circulation and adds to the second problem of "plating" or sticking to the hot metal surfaces. As the plating occurs over time, a layer of insulating material develops and reduces the amount of heat the coolant can take away from the metal components. Because the coolant can't remove this heat, the heat stays in the metal and produces "hot spots" or high heat areas.
These high heat areas will prevent proper cooling of the component and lead to cracks that increase in size and depth until major failure occurs. As a third problem, these high heat areas attract more of the insulation materials to plate, perpetuating the insulation problem.

Extended Life Coolants

Extended Life Coolants are often referred to as organic acid technology coolants. Our approved ELC uses carboxylate type organic acids, (alkyl monoacid and alkyl diacid) proven to provide metal corrosion protection without the problems associated with inorganic material "plating" or sticking to the hot metal surfaces. Because this plating and insulation does not occur, heat transfer is improved by as much as 7% to 8% over conventional coolants.
Provided the coolant is not contaminated with other coolants or fluids and not overly diluted with water, the chemical balance remains very stable over a long life cycle. This stability offers superior corrosion protection without the periodic replenishment required by conventional coolants.

ELC TECHNOLOGY IS PRODUCED BY THE ADDITION OF ORGANIC COMPOUNDS TO PURE ETHYLENE GLYCOL.

There is a product made by Fleetguard called FleetFix that can be added to conventional coolants to add ELC technology to std. coolants.

JIM