Please help with coolant question.

I am slightly low on coolant and need to add about 1 quart. The manual says to only use Porsche authorized coolant to top the system off. However, the manual does not indicate what coolants are authorized. I am assuming it is overpriced stuff available only at the dealership. Anyway, is there any coolant that I can buy locally, Walmart, Autozone, ect, that will be fine to add? I do not want to cause any adverse reaction with the coolant Porsche has in the system, but I want to get this topped off and the dealership is closed. Any help would be greatly appreciated. Thanks, Pat

you won't find any compatible coolant at walmart or autozone. there is a brand of coolant which is supposed to be porsche supplier but it's a rare brand. for 1 qt, just get it from the dealer. it's 45/gal. not sure price on a qt.

Add that crap from Walmart, etc, and you are asking for your coolant to turn to jello!

I thought so. Thanks for the info.

Just add a quart of distilled water. You'll be fine.

Will that throw off the coolant to water ratio? How much distilled water can I add before I need to worry about that ratio?

Does anybody actually know what is special about the coolant that makes you think you can't use a coolant purchased anywhere that is compatible with aluminum engines? Even Toyota owners manuals say "use only Toyota approved coolant supplied by your Toyota Dealer ...". It is nothing more than a marketing ploy intended to improve loyalty to the Dealer. I should know, I work in marketing for one of those companies. Coolant purchased at Walmart is not likely to turn your existing coolant to goo as long as you purchase a coolant that is compatible with aluminum engine blocks (and change it a specified intervals).

http://www.renntech.org/forums/index...&st=0&p=18113&

You are supposed to use a 50/50 mix of coolant and distilled water. There are approx 25 quarts of coolant in the system. So topping up with a quart of water instead of 1/2 quart water and 1/2 quart coolant only puts about 4 percent more water in the mix (if my math is correct and if the current mix really is 50/50). Water transfers heat more efficiently than coolant, so your car should run slightly cooler but be slightly less able to withstand freezing. Unless you are in Alaska, the extra water won't make a significant difference.

Tool Pants, thanks for the link to some more knowledgeable conversation on coolants (no insult intended to the first few posts here but the knee-jerk "use Porsche approved ..." is usually folly). There was one post in there about mixing coolants causing the resultant mix to turn into jello. I sincerely doubt that would happen if you mixed in an aluminum friendly coolant - it sounds like a "wives tale" to me. Also, the thought that the coolant that came in the car from the factory should last a lifetime seems suspect to me, although there is nothing to be gained by Porsche in recommending this (unless they believed most cars would require RMS replacement at some point, which would allow them to change the coolant in the process ;-)

Realist, I think you are right about the 'jello' as long as it is phosphate free coolant. I did an experiment mixing Prestone Extended Life (from Autozone!) with the coolant from my car. I heated the mixture to 180 degrees several times on the stove and let it sit for a couple of weeks. It did not gell. Since I bought my car used it is possible that the existing coolant wasn't Prosche coolant and it is possible the gelling process takes longer.

Who has the answer . I work on 996 engines everyday, I have not seen any corrosion problems yet , we have found a replacement collant but you half to buy mass Amounts, we just use the coolant from porsche , I want to sleep good at night

If you drain you old coolant (should do every 3 - 4 years), just replace it with any brand name coolant mixture. I use PEAK from Menards. $5/gallon for a total cost of about $30.

If you add 1 quart of water you'll only be short 1/2 quart of coolant. That will change the mix by only 2%. I'd just add some bottled drinking water. The Pentosin G12 antifreeze uses phosphate free organic acid additives. It's supposed to be a lifetime coolant. Porsche reccomends changing it every 5 years on the turbo. I've read everything I could find on it but no one seems to know if it is compatible with the more readily available coolants like dexcool.

Is the Porsche Coolant the same as VW/Audi G12? If so then Havoline Dex Cool will work just fine.

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?

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

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!

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?

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.