Not all RV antifreeze is created equal

Not all RV antifreeze is created equal

By Russ and Tiña De Maris

abarndweller on flickr.com

If your rig is sitting in cold country and you haven’t already done so, it’s high time to get it 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 discussing winterizing 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 nontoxic 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 nontoxic 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 Walmart? 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, Arctic Ban -50. It is made with ethanol.

What do we use? Ha! 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!

##RVT824

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10 thoughts on “Not all RV antifreeze is created equal

  1. Tim

    The old rule of thumb is if it is non toxic to humans and animals it has the ability to grow algae.

  2. Glenn Shindler

    Normally parked in a mild climate during the winter months, I don’t need to winterize. But during late fall or early spring trips away from Southern California we sometimes hit freezing conditions. All freshwater is inside and protected from outside temps. For the shower drain trap and the holding tanks we carry rock salt and dissolve it in hot water. Much less expensive, lighter in weight, and more compact than liquid antifreeze, I’ve never read any reports of others who do the same. Wonder why?

  3. Martin

    A few years ago I captured a gallon of used antifreeze, when I was going to use it the next fall it had stuff growing in it like algae very nasty looking. I only use fresh now and sanitize my system every time I drain the antifreeze.

  4. Eric Meslin

    We spent November parked in our son’s driveway in Maine. Temperatures ranged from high teens to low forties, but mostly from a low in the mid-twenties and a high in the mid-thirties.. We stayed in the house but were leaving for our home in Florida after Thanksgiving, so I didn’t want to go the whole winterized route. I heated the travel trailer to 50 degrees for the plumbing, pump, and tanks. I was concerned about the exposed pipe at the dump valves so I added a gallon of the Walmart brand RV antifreeze at $5 to both the grey and black tanks.

    I can’t tell you anything about the taste afterward, but I can attest to the sensor cleaning ability of this product. They haven’t been so clean since they were new. I’ve used other products that didn’t work half as well.

  5. Marmot

    Might your water pump freeze if you don’t run antifreeze through it? Blowing air through the system won’t clear the water pump of water, will it?

  6. JB

    When I worked in the oil field in Alaska,and the Rockies,in wintertime we always used air to blow out water lines and if done properly never had a problem with freeze ups. Of course air is not always available in enough quantity to do a good job of removing water from lines,but most small tank type compressors will usually do it if you have a little patience. Many newer coaches have water manifolds installed so the on board water pump can suck RV antifreeze out of a jug thereby winterizing the water pump.You have to winterize that pump..or it will freeze..and possibly break.

  7. David Pritchard

    I enjoyed your well written and easy to understand article. I do however note the article misstates that antifreeze raises the freezing point of water. Antifreeze widens the range water remains a liquid – lowering the freezing and raising the boiling point. Correctly stated from the article’s and an RV-er’s perspective, it lowers the freezing point, not raises it.

    1. TR

      Yes, from a chemist.

  8. Jim Stein

    Alcohol-based anti-freeze is already diluted to 50 or 60 percent. While it won’t evaporate in a closed system it will progressively dilute from residual water in the RV . It’s so cheap, why re-use?
    That said, I strongly recommend using propylene glycol. It gives better freeze protection and is safe for human consumption. If you read labels, you will find it as an additive in many packaged foods.
    In my experience, it has little taste or odor and flushes out quickly.
    I have owned a number of RVs and have never had freeze damage and it get below 0 here most winters. Hey, it’s only a few bucks more.

  9. Wolfe Rose

    1) does ethanol or glycol based antifreeze have a different freezepoint? Freeze behavior (yes, AF does freeze into slush but doesn’t expand like water!)?

    2) I’ve never tasted antifreeze, but I explicitly drain and flush it in the Spring, rather than some who logorithmically dilute it to death with fresh water. I assume the $2 AF is ethanol?

    3) funny you mentioned RVers recycling with buckets. Just this year someone asked if I recycle back into the RV between seasons since my air+AF winterize and Spring drain routine recovers almost pure antifreeze. I don’t because I want the maximum protection for $2, but wonder how much efficacy I really lose? It can’t evaporate in a closed system, but does it age or denature?

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