diitto

Hi... My '12 GS Convertible just turned one year old. I noticed today that the coolant is just a small amount below full cold. I'm new to Dex-cool so help me out here...

The manual says, "Use a 50/50 mixture of clean, drinkable water and DEX-COOL coolant. If using this mixture, nothing else needs to be added."

I see that anti-freeze vendors like Prestone make a "Dex-cool. Is it ok to use something like a Prestone version of Dex-cool or should I buy coolant directly from GM???

And regarding the water to mix with the Dex-cool, see where the manual says (in more than one place) to use "drinkable water". But that seems to imply tap water and I saw many posts that said "do NOT use tap water"...

So is distilled water ok??? Or what regarding water???

So help me out both with respect to which Dex-Cool (Prestone versus GM?) to buy and what water to mix with...

thanks... bob...

JW Motorsports

The Prestone coolant is fine. I buy it pre-mixed. Sorry can't help with the water question.

CheeseHeadNinja

Use distilled water

gar4403

The first thing I did when I bought my 05 2 years ago was the coolant change. I used the Prestone Dexcool and distilled H20 with no problems. This was the best combination I decided after research and feedback from the forum. My 2cents.

SSTEVEGS

I think the 50/50 pre-mixed is more expensive. I recently flushed my system 3X using 6 gallons of distilled water. Used the full strength dexcool and saved a little money. My original dexcool was 5 years old and 41,000 miles. It still looked brand new when I drained the old stuff. I bought Autozone's brand - same stuff.

Gearhead Jim

When I sent a sample of my 2009 factory-fill Dexcool to a lab, they said it had excessive hardness and they always recommend distilled water.

Tide Will Roll!

Get the dealer to top it off for you

diitto

My local parts store stocks the AC-Delco Dex-cool (orange). I bought a gallon and mixed up a second bottle of 50% each of Dex-cool and Distilled water...

Only required about a pint to bring it up to Full Cold but I like the water to be full...

Does anyone know where the water goes in a new car with no obvious leaks??? Are there always micro-leaks that cause small amounts to vaporize over time???

Just curious... Anyway, thanks for the help.

bob....

NoRuls

I doubt if GM makes any antifreeze so chances are your getting Prestone or another premium brand. Absolutely use distilled water especially if your on well water. When I changed the water pump on the C4 I had AC Delco recommended distilled water in the instructions. It probably has something with the alu. blocks.