RV Doctor – Stuck Antifreeze Check Valve

author image

January 29, 2009

Dear Gary,

I was winterizing my RV and pushed on the check valve in the city fill to let the antifreeze out but the antifreeze kept flowing out. I had to run and turn the pump off. Is the check valve broken now or did it snap out of place? If it is broken, can I just replace the valve? It’s a brand new RV!

–Kim Young, (Mundelien, IL)


Kim, chances are the check valve return spring simply did not allow the valve to seat properly. With the pump turned off, try pushing in and allowing the valve to snap back a couple of times. Use the eraser end of a pencil to push it in fully and then release it quickly. Then turn the pump back on and see if it didn’t spring back normally. If it will not seat properly, replace the city water inlet. Of course, you can always simply install a second backflow preventer directly to the outlet of the city water inlet too. I’m a fan of the brass backflow preventer; I would avoid a plastic check valve.

(Please feel free to comment, however, please also note that due to the volume of communications I receive from multiple channels I cannot guarantee a personal response in every instance. However, questions of an overall general interest may be considered and published in an upcoming RV Doctor column.)

Leave a Reply


  1. charles

    Thanks. “now I see said the blind man” (sorry if this is not PC anymore)

  2. Ernie Hadfield

    I assumed that he is referring to the city water connection check valve, since the antifreeze inlet valve is usually manual or electric.

    Also, some people winterize thru the city water connection.

  3. charles cox

    A dumb question. what is the antifreeze check valve and where is it located? I have a 1991 class c Tioga thanks.

  4. Ernie Hadfield

    I have an 03 Winnebago Journey. The first time I winterized it, the check valve did not reseat. I found out that the o ring had slipped out of place so no amount of gentle reseating would solve the problem.

    I put the o ring back in its groove and have had no further problems.