Suction Issues Using -100° Anti-freeze

Basil48192

I know there are a lot of discussions about suction/siphon issues with the Nautilus system...but I have a unique observation.  I've always had good luck with my 'siphon' system...whether winterizing or refilling my fresh water tank while camping.  However, while winterizing this year, I noticed an issue that might explain why a lot of people have trouble.  

I bought my anti-freeze from a boating supply store near my home.  They had two types.  One was rated for -100°F, 100% propylene glycol with no alchohol.  It was only a few bucks more than the -50° stuff...so I thought it was a good choice.  I noticed it was much thicker (more viscous) and seemed to by a lot more 'slick'  than the pink stuff.  My pump did suck it up....but the system never reached a high enough pressure for the pump to turn off.  It flowed from my faucets very slowly, but only after multiple stops and starts.

My guess is that the lubricants in the anti-freeze might cause a lot of slippage in the pump, preventing it from building up pressure.  I didn't feel comfortable with this...so I flushed the system with clean water (which allowed the pump to work normally again) and repeated the process with the pink stuff.  

Bottom line....I wonder if the lubricants and anti-corrosion additives in some products prevent the T@B pumps from generating maximum pressure (and suction)?  

bergger

Interesting.  What brand antifreeze was it?  I use the prestone -100 and it is the same color and does not appear any thicker than the other stuff.  The pump on our 400 sucks it up with no problem at all.  

Basil48192

@bergger - Sorry, I don't remember the brand...and I threw away the bottles!  It was blue in color and had the viscosity of a thin motor oil.  Very strange.  Never had a problem with the pink anti-freeze.