How do I find out what the fuel/gas capacity is?

[WILDEBILL308]

Bill I'm a little confused which doesn't take much. Why are we looking for a switch? What would a switch do?  The picture shows that both tanks are connected to each other by a common hose. There is no valve in the line so that means that as one tank is being filled, gas would flow over into the other tank through the line. And when the fuel is being used, both tanks would drain evenly. Am I missing something?

In all the systems I have had and in all the ones I have looked at there was a remote valve(it might be internal) between the tanks. I was asking fltraveler to look for the switch that controls the valve and it should switch the gas gage to the outer tank at the same time. The way this is set up when he filled the tank with 41 gallons if there was no valve he would have been making post about how fast the gas gauge went down as it equalised the amount of fuel in/with the outer tank.
The auxiliary tank is mounted higher than the stock tank. With out hands on I don't know if the fillers are at the same height (if they can find one) so it could be possible to fill the higher tank and have it overflow out of the lower tank. If you have to fill from the original and let it backflow you will only be able to use about 3/4 of the other because it is higher and won't fill. I still think there is a valve controlling flow between the tanks or the OP would have seen the gas gage go below 1/2 tank in a short time, say 30 min as the tank levels equalised.
Bill

 

[WILDEBILL308]

Firstly, I'm a she.    I have already stated all that my friend told me. And all she knows is whatever was told to her when she purchased it. That one flows into the other.  She said it is weird and very slow. Like basically fill, wait, fill again. The reason for everyone giving suggestions here is because people have said things like its very unlikely that there isn't another fill valve or switch or anything. That's why I have been investigating. To figure out if there is something that she was missing that I am also missing. We haven't filled it anywhere near 100 gallons and haven't had any sort of strange drop in fuel that would indicate it being "full" and then all of a sudden "not full" from draining into the other tank. My friend knows nothing more than what vibe already shared with you all. I'm not trying to waste anyone's time or kind help. My husband and I are both super newbies that spontaneously purchased a 23 year old RV. My husband is not mechanically inclined or very knowledgable about automobiles and the like. So we are learning as we go and trying to figure out some of the oddities of this RV.

You may be better taking it to the authorised dealer and have them examine it and tell you what's what and what it would take to make it work.
Bill

 

[Quillback 424]

In all thep systems I have had and in all the ones I have looked at there was a remote valve(it might be internal) between the tanks. I was asking fltraveler to look for the switch that controls the valve and it should switch the gas gage to the outer tank at the same time. The way this is set up when he filled the tank with 41 gallons if there was no valve he would have been making post about how fast the gas gauge went down as it equalised the amount of fuel in/with the outer tank.
The auxiliary tank is mounted higher than the stock tank. With out hands on I don't know if the fillers are at the same height (if they can find one) so it could be possible to fill the higher tank and have it overflow out of the lower tank. If you have to fill from the original and let it backflow you will only be able to use about 3/4 of the other because it is higher and won't fill. I still think there is a valve controlling flow between the tanks or the OP would have seen the gas gage go below 1/2 tank in a short time, say 30 min as the tank levels equalised.
Bill

The last half of the last sentence says it all. Amazing the talent we have on this forum!

 

[Rene T]

The auxiliary tank is mounted higher than the stock tank.

Bill, looking at the pictures, I don't know how you surmise that the larger tank is mounted higher than the stock tank. True the bottom is higher but it could also be that both tanks are pretty much up to the bottom of the RV floor and the larger tank is not as deep as the factory installed tank. I agree that it has to be put up on a lift and a hands over hands inspection get done. I would not waste my money. A mechanically inclined person should be able to crawl under the rig and figure it out.

 

[Quillback 424]

Bill, looking at the pictures, I don't know how you surmise that the larger tank is mounted higher than the stock tank. True the bottom is higher but it could also be that both tanks are pretty much up to the bottom of the RV floor and the larger tank is not as deep as the factory installed tank. I agree that it has to be put up on a lift and a hands over hands inspection get done. I would not waste my money. A mechanically inclined person should be able to crawl under the rig and figure it out.

Well, you've achieved over 7000 posts with such drivel. Is it really necessary to pursue trite comments such as this just to achieve 8000?

 

[Rene T]

Well, you've achieved over 7000 posts with such drivel. Is it really necessary to pursue trite comments such as this just to achieve 8000?

It's not drivel but facts. Pictures don't lie. But we can only see a portion of the tanks.

 

[Quillback 424]

It doesn't appear to e a black tank Rene, so you are out of your element!

 

[fltraveler]

rvforum.net: "The friendliest place on the web for anyone with an RV or an interest in RVing."

Thank you to  those that have been FRIENDLY and helpful and kind.

Quillback - I think you may need find another forum. You're killing the friendly spirit. Everyone of your posts have been negative.

 

[Quillback 424]

rvforum.net: "The friendliest place on the web for anyone with an RV or an interest in RVing."

Thank you to  those that have been FRIENDLY and helpful and kind.

Quillback - I think you may need find another forum. You're killing the friendly spirit. Everyone of your posts have been negative.

You need to understand that nobody has a wrench long enough to reach out and fix your problem. Sometimes it takes a little chiding to get people to move to help themselves. Sometimes we just need to pat them on the butt to get them to move.

Sometimes, people just decide to live with what they have, problem or no.

Have you made up your mind yet as to which way you want us to go? It's always your decision.

 

[richardhufford]

fltraveler, I think the tanks should behave exactly as your friend described them.  You have a 36 gallon tank and a 63 gallon auxiliary tank, which is 99 gallons--close enough to 100 for me!  There's a good sized hose at the bottom, so if the system works, it makes sense that you could fill the main tank but it might take a little time for the gas to make it from the main tank to the auxiliary tank.  When you fill the main tank, fuel will flow into the auxiliary tank until the levels equalize, so you fill and wait and then fill and wait and so on until both tanks are full or you get tired of pumping gas.  (It seems to me that, for the system to work, there should either be another hose connecting the tanks at the top or the auxiliary tank should be vented to the outside.  Otherwise, there would be an air bubble at the top of the auxiliary tank that would push back against the fuel coming in.)

 

[fltraveler]

You need to understand that nobody has a wrench long enough to reach out and fix your problem. Sometimes it takes a little chiding to get people to move to help themselves. Sometimes we just need to pat them on the butt to get them to move.

Sometimes, people just decide to live with what they have, problem or no.

Have you made up your mind yet as to which way you want us to go? It's always your decision.

I have done the following things:
- gotten as much info as I can from past owner
- researched online
- asked questions here
- looked all around for a fill valve
- looked inside for a switch
- climbed UNDER my RV to see what I can see
- and mentioned that if we really want to figure out I may end up having to take it to an authorized dealer for the company where the ad on tank came from

All this while parenting and homeschooling my kiddos, deep cleaning our new to us RV, and preparing a bday camping trip for this weekend for our soon to be 8 year old.

I'm not sitting on my rump doing nothing. I've been quite active. No butt patting needed to get me to move. My original question was how to tell how many gallons the tank is. I've figured that out. It has since gotten much deeper as we explored our particular RV.

 

[Quillback 424]

You could go to an authorized dealer for recommendations and ask them if that bottom line between the tanks could be changed out for a much larger one. Others could do the same job.

You may want to ask how the auxiliary tank currently vents, and what it would take to improve this.

 

[fltraveler]

Thanks for he helpful suggestions. What does "vents" mean?

 

[Lou Schneider]

When you add fluid to a tank, there has to be a way for the air it is displacing to escape from the tank.  Likewise, when you drain the tank air has to get in to replace the removed liquid.  Usually this is via an opening, or vent, at the top of the tank.

 

[Sam!]

If you take it to a shop or tank dealer, I would ask for the tanks checked for rust inside. Via inspecting fuel filters.
Inspect condition of all hoses fuel line going to motor.
Evaluate if system is safe and capable or update for easier use.
My old class c has two tanks the metal one is starting to rust. But does have a tank select switch and dual fill ports.
What RV is all this on?
Keep us posted

 

[BIG JOE]

Thanks for he helpful suggestions. What does "vents" mean?

"Vents"= in your case, Tank Vent.

Your main fuel tank "Vents" air, as it fills, through the Filler hose/fuel cap assembly (door ?).

The one picture you posted, of that looped hose.. I'd bet, is the air vent hose from the Aux fuel tank.. to the main tank. ALL the air then vents from Both tanks, through the main tank... Air Vent.

Let us know how it worked you for you.. after you've had it looked at ?

Joe 

 

[Quillback 424]

Exactly as Lou has said.

If the aux tank does not have a vent it isn't possible to add very much gas to the aux tank since the air already in the tank is being trapped at the top of the aux tank. At some point, the air being compressed in the aux tank equals the "weight" of the gas in the main tank and no more gas will be forced from the main to the aux via gravity. So, you could never fill the aux tank to its stated capacity.

If your system has an air vent tube between the top of the aux to the top of the main tank, this would allow the air to escape from the aux tank as it is being filled, and allow air to be admitted to the aux tank as gas is being used.

So, with proper venting of the aux tank and proper sized line from main to aux for filling (or consuming) gas your gas gauge would indicate approximately how much total gas remains in the combined tanks, maybe not the full 100 gallons but certainly much more than 40.

 

[Rene T]

It doesn't appear to e a black tank Rene, so you are out of your element!

Really?  :

 

[MN Blue Skies]

rvforum.net: "The friendliest place on the web for anyone with an RV or an interest in RVing."

Thank you to  those that have been FRIENDLY and helpful and kind.

Quillback - I think you may need find another forum. You're killing the friendly spirit. Everyone of your posts have been negative.

Amen to that

 

[kwbush]

WOW...