I don't know what Zerex prices are but to me price isn't the issue here. If BMW provides the only 'safe' coolant that's what the vast majority of us would purchase.

I see anti-freeze as a simple formula that would quickly be reverse engineered to be able to serve a notable size market. If German vehicles, or just BMW, had a monopoly on coolant for their vehicles because it was so unique and necessary, there would be appropriate coolant on the shelves labeled specifically for those vehicles.

We don't have unequivocal performance documentation of more complex aftermarket parts we purchase for our BMWs. BMW recommends the oil we use and look at the discussions that generates, pages and pages of other preferences. I use Royal Purple oil and I don't use a BMW filter. How many of those out there would say it is not suitable or the wrong stuff, or, if bold enough, would tell me I am nuts?

Because of the importance of the brand name of companies like Zerex and Prestone, and the amazing amount of communication that now happens in a matter of seconds, verification of the accuracy of technical information and marketing lingo disseminated is a critical issue. Of course there are mistakes still made but I don't believe any company could get away with a coolant offering this long and not have a multitude of threads on BMW forums ranting about how a particular coolant destroyed their cooling system---there would be no question by now.

Even 20 years ago, companies in for the long haul were very brand name sensitive. While marketing was tasked with finding ways to communicate their products in the best light possible and at least appear to be better than competition, they were as careful even then.

In my case, an Autozone is 5 miles away and the nearest dealer is 15.

Advance auto sells Prestone extended life coolant for $13.99 a gallon undiluted. At 70 percent coolant it provides protection to -84 degrees which should be good enough for most places this winter. At 50/50 mix protection is at -34 degrees. This is per the website.

I don't think we need a prize winning chemist to draw our own conclusions about antifreeze, ever had a doctor miss the mark?

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas