Leave tank drain open after antifreeze? - Fiberglass RV

Thread Tools Search this Thread Display Modes
Old 01-01-2016, 01:54 PM   #1
Name: denny
Trailer: 2001 Scamp 16 layout 3
Posts: 37
Leave tank drain open after antifreeze?

Winterized trailer with antifreeze in water tank. Pumped it thru sink faucet and drain and it drained into and out of the grey tank. Then I opened the fresh water tank to drain as much as possible that the pump left in the tank (still has a tad that would not drain out the drain valve). Now do I close the tank's drain valve or leave it open? If left open will it dry out the tank to prevent mold? Will spiders/other crawl inside? If close it won't that result in the leftover water/antifreeze producing slime and mold? Trailer will sit till Spring. What should I do?

denny w is offline   Reply With Quote
Old 01-01-2016, 01:59 PM   #2
Senior Member
Bob Miller's Avatar
Name: Bob
Trailer: 1973 Hunter Compact II
Posts: 7,914
As there should already be an air vent that can't be closed, I always close the drain valve just so that I don't get my feet wet when I refill the tank.

Bob Miller is offline   Reply With Quote
Old 01-02-2016, 11:09 AM   #3
Senior Member
Name: Gordon
Trailer: Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 1,245
I doubt you can get the tank and lines completely dry as a method of preventing contamination. If you could get ALL the water out then you would not have to winterize. The drain valve and tank are not designed to completely drain the tank, let alone the plumbing. You might get close using compressed air however.

According this this web site, RV antifreeze in the proper mix does have some ability to prevent tank and plumbing contamination. But if the concentration is too low it actually encourages the growth of microbes.

In addition, RV antifreeze lubricates the plumbing and helps to prolong the life of seals.

So, concerns over wet feet aside, it probably makes little difference if the drain is open or closed during winter storage. I would close it just to keep insects out.
gordon2 is online now   Reply With Quote
Old 01-02-2016, 12:47 PM   #4
Senior Member
Name: Wayne & Barbara
Trailer: Parkliner
Posts: 322
Keep RV antifreeze in the tank with drain closed.

When you are ready to flush the A/F out in the spring, you can get more of it out by tilting the tank toward the drain. Do that with the hitch jack. either up or down , whichever does the job. Open the drain then flush remaining A/F with numerous small amounts of fresh water. Close the drain, level the trailer, fill the tank, turn on the pump, and flush the lines and water heater. Finally, drain the grey and black water tanks.
Wayne Collins is offline   Reply With Quote
Old 01-03-2016, 07:19 PM   #5
Senior Member
Name: Darral
Trailer: Scamp Standard 13' 2010
Posts: 1,124
I never leave my valves open...period!
Darral T. is offline   Reply With Quote
Old 01-04-2016, 06:19 AM   #6
Senior Member
Donna D.'s Avatar
Name: Donna D
Trailer: Escape 5.0 TA, 2014
Posts: 23,908
Lots of folks have put deck plates in fresh water tanks so they can thoroughly dry and sanitize those tanks. Of course you have to be able to get to it and that depends on the build. Little House Customs sells a cap that replaces the drain caps for the black and gray tanks and has a screen to keep critters out, that allows those tanks to dry out. Something to consider.

Donna D.
Ten Forward - 2014 Escape 5.0 TA
Double Yolk - 1988 16' Scamp Deluxe
Donna D. is online now   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hot Water Tank Smells Like Antifreeze kdhanso Problem Solving | Owners Helping Owners 3 03-24-2012 11:07 AM
An antifreeze pump mod for winterizing the black tank cpaharley2008 Modifications, Alterations and Updates 1 01-13-2011 11:46 AM
Hot Water tank done...split wide open DwayneR Problem Solving | Owners Helping Owners 3 05-10-2009 05:28 AM
holding tank antifreeze? Legacy Posts Problem Solving | Owners Helping Owners 6 02-17-2003 10:43 AM
RV Antifreeze Legacy Posts Care and Feeding of Molded Fiberglass Trailers 9 09-27-2002 11:04 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 05:58 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.