Antifreeze for C2's -- Orange vs. Green

[Wayne M.]

Decided to replace stale Prestone Green with fresh. There are so many formulations and colors out there that I'm totally confused (see link below). Thought I'd post here to get opinions narrowed down to our old, familiar, cooling systems, that have endured many years with silicate-based corrosion inhibitors, and that are equipped with aluminum radiators and brass/lead solder(?) heater cores. I intend to use distilled water for a 50-60% blend.

Seems that DexCool is over twice the price of Prestone Orange, and Prestone Green is getting very hard to find (at least in Canada).

http://www.popularmechanics.com/automotive/sub_care_sat/1272436.html

[Duke W.]

Re: Antifreeze for C2's -- Orange vs. Green

The industry consensus is that hybrid organic antifreeze technology (HOAT) products are the best replacement for the old inorganic antifreeze technology (IAT) products, which is what "green antifreeze" is, and it is being phased out of production because OEMs no longer use it.

Organic antifreeze technology (OAT) is available in a couple of major formulations. One is Dexcool, but it has one component that the Japanese OEMs don't like as there is some evidence that it hardens plastic, so they use a slightly different chemistry that deletes one Dexcool component.

There is also some concern that OAT types may not provide adequate protection for solder joints - such as our old heater cores.

So HOAT is the best choice and the best HOAT, IMO, is Zerex G-05. This is the exact same formulation that is used in ALL new Ford and DC products, worldwide. It has been used in all new Mercedes-Benz vehicles for over 20 years, and it is widely available at auto parts stores.

IAT, OAT, and HOAT refer to the corrosion inhibitor chemistry. All, with a couple of exceptions (like Sierra brand) are ethylene glycol based, and I would not use any other base in a car I own.

OE cooling systems are designed to function properly with a 50/50 mix of ethylene glycol antifreeze and water. This blend provides proper heat capacity, maximum corrosion protection, and has a boiling point of 265F with a 15 psi cap, and a feezing point of either -34F or -45F (I forgot!)

I always used distilled water so as to not add any "foreign" chemicals to the blend. In particular, chlorine that is often added in small quantities to domestic water supplies is corrosive to cooling system components.

Duke

[Donald B.]

Distilled Water

Can I use tap water that has been processed through a Reverse Osmossis system?

[Joe L.]

Re: Distilled Water

Don-----

Yes, you can. RO-purified water is the equivalent of distilled water, for all practical purposes. In fact, much of the "purified" water sold today is actually produced using RO rather than steam distillation.

[paul bowers]

Re: Antifreeze for C2's -- Orange vs. Green

Duke;
I as very impressed with what you had to say in regards to antifreeze my (?) is would the same go for a c1 car with a brass radiator thanks
paul

[Duke W.]

Re: Antifreeze for C2's -- Orange vs. Green

Yes. Zerex G-05 is the best antifreeze for any vintage car with a brass radiator or heater core.

Duke

[Jim T.]

Re: Antifreeze for C2's -- Orange vs. Green

Duke what is best for a brass radiator and heater core older Corvette with newer engine having alumimum heads and intake? It is time for me to change the Dex-Cool installed with distilled water.

[Duke W.]

Re: Antifreeze for C2's -- Orange vs. Green

Zerex G-05. This is the new "universal antifreeze". It provides excellent protection for cast iron, aluminum, brass, and solder, and it is not considered to be a "plastic hardener".

There have been some problems with Dexcool and some owners of late model GM cars refuse to use it. Many have replaced Dexcool with traditional "green" antifreeze, which I think is a mistake.

I recommend that owners continue using Dexcool in cars that had it as OE, but if you insist on using a different blend, I would not be against Zerex G-05 or an equivalent HOAT blend.

All my cars now have Dexcool, but at the next change I'm going to install G-05 in all but the '91 MR2, which will continue with a diet of Dexcool.

Duke