Frozen antifreeze?

Look at the MSDS on RV anti freeze. It gels at 9 degrees. I have posted several times that the RV anti freeze does freeze just not hard. One of the main reasons I don't use it is I winterize and de-winterize several times in the winter. Once it has gelled you may have to wait until spring to get it all out of the lines. YUK!!!!!! I just blow out my lines with air and only put RV anti freeze in the traps, toilet and a little down in the grey and black tank to protect the dump valves. I have a W/D so I put some in my washer and spin it out through the drain to fill that p trap.

Was it frozen solid, or just slush? There is a difference.
If you got all the water out, and had pure "pink stuff", you should have been fine....it will turn to slush, but not freeze to the point of damage. After all, slush can still move in the lines, so it won't expand out-ward, busting tubing.

The one think you didn't mention, or you didn't do, was to pump antifreeze into the water pipes after you blew them out. The reason I recommend this, is because you may still have water in those lines, where the air has blown past it (say in a dip in the hose)....if you pump the pink stuff through the lines, you know that there won't be any water to freeze. Well worth the extra $$ for another gallon or two.

It is good to -50 before it expands BUT it will freeze before that. Yes, I know that's strange but it's true.

You might of gotten a bad batch of antifreeze, either that or it got diluted, It should of never been frozen under those temps.

I think that the pink stuff can freeze, but does not expand.

It doesn't exactly instill confidence does it?