Antifreeze question and concerns

[Aaron P]

Hello all in AS land....

I have a question regarding RV antifreeze. I live on the coast of Maine, in a fairly rural area. I store my AS outside, as I do not have a garage big enough for inside storage. As you can imagine, I winterized my AS this fall. I blew out as much water from the lines as I could with a compressor, and then pumped pink RV/marine antifreeze through all the lines, and poured a healthy amount down the drains and into the toilet bowl.

We have had some pretty cold weather here, even for Maine, with some nightly lows in the single digits (all temps are Fahrenheit), and even a couple below zero. The lowest temp at my house has been -3 so far.

This morning, the temps rose slightly above freezing for the first time in several days, so I decided to check out the interior of the AS, as I knew the door seal would not be frozen shut. I checked out the antifreeze in the toilet bowl, and it was frozen solid. I had some leftover antifreeze stored in my unheated garage, so I looked at the label, which says that it protects against bursting to -50 degrees! The antifreeze in the plastic jug was slushy, but not solid. So, what's going on? Any advice would be welcome. This is my first winter storing the AS outside, so it's my first experience with winterizing.

Thanks.

[richard5933]

The pink antifreeze should properly be called 'anti burst' not antifreeze.

Water freezes at about 32F and will begin expanding, thus causing all sorts of damage. Liquids like the pink antifreeze will also become solid, but they have a big difference. They don't expand until they reach the temperature on the label.

I use the -75F pink stuff. It certainly turns to a solid at about 32F. But, it doesn't expand so it will not cause any damage.

The antifreeze used in automotive applications is specifically designed to stay liquid till the temp on the label. Since you may need to start/run an engine in the winter, it is vital that the coolant be able to flow through the pumps and all the orifices of the engine. An RV doesn't have needs like that - we don't usually ask our water pumps to function when they are below 32F so it doesn't matter if the stuff turns solid. It only matters that it doesn't expand.

Making a food-safe antifreeze that truly doesn't freeze would be much more expensive than just making stuff that doesn't expand, and that's why we use what we use.

[Aaron P]

To richard 5933:
Thanks very much for the concise and kind reply. It makes perfects sense, now that it's been explained. I had no idea that it is really "anti burst" antifreeze. Thanks again for putting my mind at ease.

[SlowPokePete]

Very interesting.

SPP

[Rich W]

Originally Posted by Aaron P

[...snip, snip] I checked out the antifreeze in the toilet bowl, and it was frozen solid.
Thanks.

My first winter with our AS I put RV antifreeze in the bowl. When I cleaned out the RV antifreeze for summer I found the rubber toilet gasket to be warped, causing a slow leak in the bowl. As summer wore on the gasket corrected itself and all was fine. The second winter, and afterward, I used Oatey's Plumber's silicone on the seal, nothing in the bowl. No problems since then, 7 years now. We just went on a trip for 2 weeks after the AS had been sitting for 2+ years and the toilet worked just fine, no gasket leak.

Others have used other products, some use RV antifreeze, but the Oatey's product (Lowes, Home Depot) states that it's safe for all rubber and plastic seals. Good stuff.

[richard5933]

Originally Posted by Rich W

My first winter with our AS I put RV antifreeze in the bowl. When I cleaned out the RV antifreeze for summer I found the rubber toilet gasket to be warped, causing a slow leak in the bowl. As summer wore on the gasket corrected itself and all was fine. The second winter, and afterward, I used Oatey's Plumber's silicone on the seal, nothing in the bowl. No problems since then, 7 years now. We just went on a trip for 2 weeks after the AS had been sitting for 2+ years and the toilet worked just fine, no gasket leak.

Others have used other products, some use RV antifreeze, but the Oatey's product (Lowes, Home Depot) states that it's safe for all rubber and plastic seals. Good stuff.

Good point - not all RV antifreeze is the same, and some contains an alcohol which will degrade rubber products/seals/plumbing parts over time. I always search out the kind without the alcohol to hopefully avoid problem like this.

[Rich W]

Originally Posted by richard5933

Good point - not all RV antifreeze is the same, and some contains an alcohol which will degrade rubber products/seals/plumbing parts over time. I always search out the kind without the alcohol to hopefully avoid problem like this.

I just don't put AF in the toilet to winterize. I dry out the bowl and put the Oatey's silicone on the rubber gasket. I don't have to worry about evaporation, a warped seal or AF sloshing out of the bowl if I'm traveling after winterizing. Two years sitting idle and no issues. For me (YMMV) the silicone is a simple solution.