ebaker

Porsche uses G12, at least in the newer models, same as VW/Audi. Orient Express, do you have a reference for using Dexcool with G12?

Orient Express

Here is the Texaco-Havoline DEX-COOL data sheet. Look on page 2 for G12 compatability

itradem

So is this to say that if you top the reserve tank off with "regular old Prestone," you should be running in fear to your local dealer to have the whole coolant system flushed out??? Will a 1/2 quart of the "crappy stuff" really turn your whole coolant system into a state of jelloness???

The reason I ask is that it seems that a few people, like 1999 Porsche, have "changed" their coolant a couple times by simply draining, and then refilling with Menards brand stuff. A simple drain, at least the first time, would not have rid the system of all of the Porsche coolant, allowing the two to mix... I haven't heard of any Jello problems from 1999 Porsche...

Just want to do a sense check of this whole Jello theory...

Thanks!

Orient Express

The larger issue is running coolant that contains nitrates, phosphates, or borate compounds that would have a negative impact on the metal alloys that make up the various engine components on a 996/997 engine. in addition, it is important not to create a liquid that is high in abrasive solids that can shorten the water pump seal life.

G12 coolant is an Organic Acid Technology (OAT) coolant. Although extended life antifreeze is compatible with traditional formulas, it is recommended by extended life antifreeze manufacturers and suppliers that OAT and non-OAT formulas not be mixed. Mixing the two types negates any extended life characteristics.

Here is a handy chart that clarifies compatibility questions

Combining the organic and non-organic types of coolant that have different types of corrosion inhibitors can create the "jello" effect over time. A complete purging of the cooling system before adding a non-recommended type of coolant will minimize that effect, but why in the world would someone not replace the coolant with the correct type, especially given the wide availability of the correct types?

Realist D.

Orient Express, your response to itradem above seems clear and your knowledge level on this seems high. But your response also includes a vaguary that will perpetuate the knee-jerk, panicky and slavish allegience to "use only Porsche approved ..." which is BS. Certainly it is important to use a coolant that is compatible with aluminum engines. As you point out, you shouldn't mix organic and non-organic coolant types because "over time" it "could" create a jello effect.

The simple fact is that you would have to leave the stuff sitting in the rad for a couple of years, unattended, to have any possibility of the jello effect. But when you leave a post here like that, since you sound so knowledgeable, the guys here with less knowledge will just say "I'm not going to risk it" and pay $50+ for coolant from their dealer. That's highway robbery and the dealers don't deserve the money.

Any decent coolant that is compatible with aluminum is fine if changed every two or so years. It's that simple. It won't wreck your engine.