Man, you are taking a simple situation and trying to do as much damage as possible. First off, don't feeed the anti-freeze to the pet. Next, do a little surfing on the web about those extended life phosphate and silicon free formulas. I believe that if you read the basic makeup of the Volvo fluid on the container you will see that it is the same as Prestone. Volvo factory fluid is a pink color that really makes you think it is something special. What you buy at the dealer is very similar in color to Prestone. Some other brands are green or even blue.It's the same crap. Those extended drain fluids were the big ass deal and you possitively could not mix it with other types. That's all changed now. Just put Prestone in or if you really want to feel good about it go to the dealer and pay $16 a gallon like I do. I put Prestone in the 740.