Tech Tips: RV Antifreeze: Not All the Same

If your rig is sitting in cold country and you haven’t already done so, it’s high time to get winterized. We’ve written on this important subject before. Keeping your RV water lines from freezing (and breaking) is serious stuff. One question that pops up when winterizing is discussed is this: Is there a difference in the types of RV antifreeze?
Most RVers are savvy enough to know there’s a huge difference between RV antifreeze and automotive antifreeze. In case you missed it, here’s a quick recap. RV antifreeze is non-toxic and meant for pumping into the plumbing system. Automotive antifreeze is a whole different critter. Many types are toxic, and should only be put into an engine cooling system.

So when asking what kind of antifreeze they use to winterize their rig’s plumbing system, many RVers respond, “Oh, I use the pink stuff.” Huh? Just what is the “pink stuff?” There really is a difference in RV antifreeze formulas, and it can make a big difference on how things turn out.

There are two basic contenders in the world of non-toxic RV antifreeze. The primary components are either ethanol or propylene glycol. You may remember from your high school chemistry class that ethanol is the “kick” in Kickapoo Joy Juice—grain alcohol. Yes, ethanol is a good antifreeze (not in your bloodstream) because it raises the freezing point of water.

That other antifreeze contender, propylene glycol, is also an alcohol of sorts. Technically a “double alcohol,” this is not like a “double shot.” But like grain alcohol, it also raises the freezing point of water. For our purposes as RVers trying to keep our pipes from breaking, either one will do the job. At that point, frugal RV logic would ask, “What’s cheaper?” Some retailers would have you believe that the ethanol-based antifreeze is less expensive, and hence, the product of choice for winterizing.

But hold on to your credit cards for a minute, there’s more than money to be considered. Some RVers have reported that using ethanol-based antifreeze did keep their pipes intact, but unexpected side effects cropped up. At least one RVer says when he took his rig out of the “deep freeze” and began to use it during travel season, the taste from the plumbing was bad, and it took quite awhile to flush the unwelcome spirit out of the system. Some warn that rubber plumbing seals can be adversely affected by contact with ethanol. Since ethanol antifreeze is combustible, if you decide to use it, then by all means, keep it away from flame.

Does this mean that propylene glycol antifreeze is the choice for RVers? Here’s one more fly in the ointment. In a news release touting its own brand of propylene glycol antifreeze, Dow Chemical warns against similar products made by others—ones that could possibly be made with recycled products. Can you imagine RVers running out with buckets every spring, catching those precious drops of antifreeze, and shipping them back to some chemical plant for recycling? Nah! But there are some outfits that actually do recycle propylene glycol: airports. When your 707 sits on the tarmac on a chilly day, that stuff they spray on the wings to keep the plane from icing up is typically propylene glycol. Often the runoff is captured and sent to a recycler. The recycled product, warns Dow, could come to you along with other chemical nasties that might not be so potable.

How do you know if your brand of propylene glycol RV antifreeze might contain recycled materials? You wouldn’t from looking at the label. Dow, of course, makes a big noise about its materials being strictly “virgin” in every jug of Dowfrost. To save you trouble, we checked with manufacturers of other popular RV antifreeze brands. Shop at Wal-Mart? Its house brand, Super Tech RV and Marine Antifreeze, is virgin pure. Likewise is Camco’s Easy Going -50 brand. Keep a weather eye open on its other brand, Artic Ban -50. It is made with ethanol.

What do we use? Hah! We don’t worry about taste or plumbing deterioration problems: When we winterize, we use air pressure to blast water out of our pipes. What little antifreeze we use goes down the plumbing drain p-traps. I promise you this: I’ve never tasted what comes out of there!

Russ and Tiña De Maris are authors of RV Boondocking Basics—A Guide to Living Without Hookups, which covers a full range of dry camping topics. Visit for more information.

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