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Topic: holes in floor of fuel tanks area 3 inch diameter (Read 463 times) previous topic - next topic

holes in floor of fuel tanks area 3 inch diameter

Good morning,
I have a 98 40ft U320 and have noticed there is 1- 3 inch diameter hole in the floor of each fuel tank compartment (one compartment also has the propane tank) Are they for ventilation or can I plug them up? I am worried about mice entrance during storage in winter time in Canada.
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #1 –
They should have a wire screen over them, don't seal them up. Fuel and Propane vapors can accumulate if you seal them.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #2 –
Correct-- you need to leave them.  BUT, be sure water can not get into the basement "sandwich". 

If right behind a front wheel, a good idea to built a "deflector" .  U shaped with the base of the U forward.  I use 1" aluminum box beam and cover the bottom of it with a piece of FG or aluminum (whatever I have lying around).  Retains the vent function, but water is not driven up into the screened vent area.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #3 –
Thanks for the knowledge and advice.
I guess I will have to build a deflector and a screen to keep the mice out!
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #4 –
And, may have to use some polysulfide caulk if there is any separation that could allow water into the basement sandwich.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #5 –
For the screen part just cut a piece and caulk it to the inside floor over hole and that will do.
Johnh
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #6 –
I went to a cargo or toy hauler trailer dealer And Purchase the side vent on the enclosed trailers which were only about $15 and mounted it underneath the coach they are slope with a grill opening on one side and are designed to let the air flow out or in for ventilation and keep water out just look at the side of any in close trailer they are usually mounted on the top corner
Rick & Hilda looking forward to full- timing one day for now couple of months at a time
1999 U270 3602
Built number  5530.  Feb 1999            Motorcade  number 18438
8.3 Cummins Allison six speed with brake  retarder
Purchased Nov 28 2019
 

Re: holes in floor of fuel tanks area 3 inch diameter

Reply #7 –
Quote from: dsd date=1599361445 link=msg=401909]
quote author=wolfe10 –
1877]
GET IT OUT OF THERE.

As I mentioned in a post about coach inspections, if the diesel works its way into the basement bottom it will melt the foam board insulation and as it evaporates, the insulation will reform in "globs".
 


In looking at my vents below the propane thank noticed one was loose. Pulled all three 3" vents out by hand. P.O. must of overfueled some time and fuel leaked into foam. Damaged back about 3/4 inch. Area cleaned up and reinstalling same vent tubes. I used RTV 157 Gray (Aerospace hi temputure, hi strength/adhesion to seal top and bottom. Tomarrow I will fill with fireproof spray foam applied thru 1/8 holes on top. After foam is cured will drill out foam holes and fill with RTV 157. Thank you Brett for bringing this to my attention.
Scott