The 2012 GMC Acadia requires a refrigerant known as R-134a. This is the same type of Freon that has been used in all car models since 1993 and it continues to be one of the most popular types of refrigerants available today. It's important to use the correct type of Freon when servicing your vehicle, so make sure you check with your local GMC dealership or auto parts store for more information on what kind would be best for your Acadia. Additionally, if you're looking to DIY any air conditioning repairs or maintenance, always follow safety guidelines and take precautions such as wearing gloves and protective eyewear while handling this chemical compound.