antifreeze

[STEVE1103]

Friend has a few quarts of Toyota antifreeze, is it OK to mix with other brands and use in older cars?

[Straight eight]

I would think as long as the color of the antifreeze is the same. Some will NOT mix, but I would think if the color was the same

[Bhigdog]

Not supposed to mix ethylene with propylene glycol. A better question might be "Should I risk my cars for a few bucks worth of anti freeze"?...Bob

[70 Electra]

Originally Posted By: Bhigdog

"Should I risk my cars for a few bucks worth of anti freeze"?

Bob's right. Don't take chances.

First, DO NOT go by the color of antifreeze.

Second, DO NOT mix types and brands of antifreeze unless you know exactly what you're dealing with.

Third, there is much more to selecting antifreeze than choosing from ethylene glycol or propylene glycol.

To elaborate, there are 3 types of coolant on the market. Each is available as ETHYLENE glycol OR PROPYLENE glycol, making (potentially) at least 6 types to choose from (not counting individual formulations to meet specific automaker requirements)!!

1. Silicated. This is the traditional kind we've been using since the sixties. It used to be green, but now so are other types, so DON'T count on color to tell. A coolant meeting GM spec 1825M is in this category, but you'll have a heck of a time finding this old-school coolant these days.

2. Organic acid technology (OAT). This is NON-SILICATED. GM has used it since 1996, and many other makers now use it, including VW/Audi. Many Japanese are moving to it, after a decade of Hybrid coolant. This is the most modern technology.

3. Hybrid (sometimes referred to as GO5). This is a combination of both silicated technology and organic technology (NO, you can't make it by blending the other 2 types!). Ford and Chrysler use this, and some of the Japs still do, although they're moving to organic. The hybrid was an intermediate step between silicated coolant and OAT coolant technologies.



DO NOT, I repeat, DO NOT, judge by color. GM's OAT coolant is orange, but so are many hybrid coolants. Traditional silicated coolant was green, but so are many of the hybrid coolants on the market today.

Prestone's popular 'yellow jug' coolant was, for many years, the benchmark of silicated coolant (and was green in color). Several years ago, they quietly quit making silicated coolants, and leap-frogged to the OAT coolant (bypassing hybrid) for their 'yellow jug'. This new formulation is yellow in color, rather than green. Prestone claims it is OK to mix with ANY other coolants, but automakers and other coolant makers do not agree.

So, what to use in an old car? The short answer is most any name brand coolant should be suitable for an older car, if it is installed and maintained per directions.

But I would highly recommend against mixing coolants...especially unknown ones. It's not that they'll turn to muck...they won't! But each type has a delicate chemical balance to protect the cooling sytem and mixing them defeats this and can even cause serious problems.

[Bhigdog]

Wow. Great informed answer. Greg, Since losing a dog to anti freeze poisoning I've switched to propylene glycol which is supposed to be safer. I've been told that most new anti freeze compounds contain a "bittering" agent to make them unpalateable to pets. Do you know anything about that?..........Bob

[70 Electra]

Originally Posted By: Bhigdog

I've been told that most new anti freeze compounds contain a "bittering" agent to make them unpalateable to pets. Do you know anything about that?..........Bob

Bob,
Most states now have legislation that require the embittering agent. This plays havoc with distribution, so some coolant makers just go ahead and put it in all their after market (gallon size) jugs. The laws typically exclude large (55gal) containers, and the stuff automakers install during the original build of the car.

Is it effective? From what I've been told, the jury is still out. The stuff does make the taste "worse", and that may deter children. But some individual animals actually prefer it! (I mean, after all, when you see the things a dog will put in his mouth, do you think a little embitterment will make a difference? [img]<>/grin.gif[/img]) For the most part, the embitterment is another knee-jerk reaction by our legislators, so they can say they did "something."

Switching to the less toxic propylene glycol (PG)is a good solution, if you are concerned about the danger to animals. However, note that PG is NOT "non-toxic". It can still kill you (or Fluffy), but requires a larger dose. The advertisers try to portray it as harmless, but it is not.

As you know, PG requires a different refractometer to check its concentration, because it has a different specific gravity. Also, it requires a slightly "richer" mixture than ethylene glycol (EG) to acheive the same freeze point. Neither of these items is a problem, but must be considered when switching.

As I mentioned in previous posting, PG and EG are the base stock of the coolant, and independent of the corrosion additive technology. Technically, you should be able to get PG in silicated, hybrid, and OAT formulations. However, because of the relatively low popularity of PG (due to the cost) there is a very limited selection in the aftermarket.


PS- Thanks again for bringing your beautiful 57 Special to the Meadowbrook Concours last August for "The Class of '57"!

[Bhigdog]

Thanks for the anti freeze info, Greg. Even though I use Propylene glycol, around my pets I treat it like it was Ethylene glycol . Being invited to Meadowbrook was my honor, Greg. We had a blast. The concours folks did it up right..........Bob