Antifreeze & Water

[John K.]

I just realized I've got 2 gallons of water and some tank cleaner in each of our gray and black tanks, and I won't have time to get to a dump station before storing the trailer. I'm winterizing now and figure I'll put in a gallon of antifreeze in each tank to prevent any freezing. Will that work, or should I aim for 2 gallons of Antifreeze in each tank? Or should I just remember to dump the tanks before winterizing (asked rhetorically)? Thanks.

[Grumpy]

Get a bucket and empty the tanks.

[DJL1967]

I drained mine into a bucket when I winterized this fall to assure that the tanks were completely empty. Just remember to open the valve slowly.

[John K.]

Yes, I figured I could use buckets to empty the black and grey tanks. But do you think the tanks will be OK during winter if they have as much antifreeze in them as water? And thanks for the responses; I do appreciate the help.

[Baja]

John. Don't risk it. I've looked and cannot find any table that states when a mix of water and RV Antifreeze will freeze.

It's only water and cleaner in the tanks. Drain them.

[Kenelz]

After I drain the black, I always put a couple gallons of water back in. Never drained that during the winter. There is plenty of room for the ice to expand, like a plastic ice cube tray in the freezer. You never get it all out anyways.

[Baja]

True on the expansion thing. Good to go.

[dewey02]

As others have said, get a bucket and drain those tanks.
RV antifreeze is NOT like Prestone. You don't mix it with water. And RV antifreeze actually DOES freeze at colder temperatures - it just doesn't EXPAND when it freezes, so it won't put pressure on your pipes and fittings. I'm not sure what happens when you have a 50/50 mix of water and RV antifreeze. Will the water expand? Why risk it? Get a bucket and drain your tanks. Better safe than sorry.

[norty1]

I would be more concerned with a couple of drops on the seals and valves.

RV antifreeze turns to slush when it freezes. I would drain the tanks and leave them open for a while, then add a gallon or less to each tank, each trap and each toilet. Run each faucet until antifreeze comes out. Also run the shower, both inside and outside.

[Isaacs]

It's not the water in the tank you have to worry about; I'd be concerned about any piping between the tank and your black water dump valve. I'm sure all RVs are different and if the pipe is long enough it will split when it freezes.

[hboy]

The RV Antifreeze can still freeze (around 12 degrees F). Diluted antifreeze will freeze faster and could expand at a warmer temp than pure antifreeze.

[John K.]

Just checked my trailer in storage and found the antifreeze that's in the toilet has frozen -- not slushy, but a solid block. I checked the antifreeze bottle and it claims to be good down to minus 50. We've had a few nights below zero recently but certainly not down to minus 50. I assume the pipes have solid antifreeze in them now too. I hope this is normal, and that I don't have to worry about the pipes splitting...