Community Forums

Onrecess · 10-22-2021, 09:05 AM

I have read where people said they tilt coach to top off. I thought my fuel gauge was way off. My 150 gallon tank seemed to be a 100 gallon tank.
My low fuel light came on. I filled and topped off all it would take, around a 100 gallons. I tilted the coach way over. It took over 30 more gallons! My fuel gauge registered just under fuel. Turns out gauge is pretty accurate after all.
I thought people were talking a couple of gallons, not 30+!
The truck drivers look at me like I'm nuts when I am at the pump tilted way the heck over.

vito.a · 10-22-2021, 09:54 AM

I didn't realize it was 30 gallons, but I always try to tilt it when I first pull in. That makes the side I'm filling higher and it's easier to access.
You're right, it does look strange.

FL420 · 10-22-2021, 10:05 AM

I have a couple of small bubble levels attached to the floor near my right foot. When I pull up next to a pump and stop I check the bubble that tells me if I am level, leaning towards the pump or away from the pump.
If the bubble is level or high on the pump side I'm good knowing the tank is level or the fill pipe is higher than it would be otherwise. I lower the jack on the side next to the pump to raise that side if the bubble tells me the filler pipe next to the pump is too low.
I can put about 15 more gallons into my 100 gallon tank that way. I don't do that unless I'm going to put some more miles on the coach that day to leave some room for expansion after shutdown. I pay close attention to prevent trying to drive off with a jack down even though the coach will warn me if I try to do that. I learned long ago that it's not wise to put all your trust in manmade safety interlocks and warning systems.
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Timaz · 10-22-2021, 12:08 PM

I always tilt way over like you and it does add a lot more fuel.

Tim

Onrecess · 10-22-2021, 05:50 PM

Huh. Makes a huge difference on mine. I tried it twice this month. I guess they changed fuel tank design?

bigb56 · 10-22-2021, 05:59 PM

Wow that's a lot of fuel! Diesel I assume? With those gigantic tanks I can see why it would make a big difference tilting them! My F-350 has a 38 gallon tank and I cut off the overfill tube inside the tank and now can fit about 3-4 more gallons. (It's a very common mod on the older Superduty Powerstrokes).
The motorhome actually only has a 26 gallon tank which is fine most of the time except I have to buy high priced California diesel when I go there since I can't hold enough to get me there and back into AZ.

Onrecess · 10-22-2021, 06:10 PM

Yeah, diesel. I was gobsmacked. I never would have thought 30+ gallons!

Biljol · 10-23-2021, 12:04 AM

The fuel tanks are designed to only allow you to fill to 95% of tank size this is a safety issue.

So a 150 tank must only hold 142 gal max. Of course most manufacturers have extra as a safety margin. take into account that the pickup tube will not go to the bottom of the tank and the flat bottom tanks it’s very easy that when the fuel level is below the pickup there is still 10-20 gallons in the tank.

So 100 gallon fill is actually 120 in the tank. That puts you at about 85% of capacity. You lean and get another 30 gallon that puts you above the 95% and are creating a unsafe situation.

ie.
When you lean the rv to get more fuel and you have 2 fillers one on each side your raising the level of the fuel above the filler tube on the low side this is a dangerous event especially if the cap on the far side it not well sealed you can cause a fuel spill.

There is also a DOT regulation that the full fuel level must be below the filler tube so you lean and fill but when level the fuel could be higher than the fill tube. Also with a fuel cap that may be faulty as you turn corners or have elevation changes fuel due to slosh you have fuel higher that the cap and now your have leak/fuel spill.

If having another 30 gal is a big deal add another tank it’s safer and legal.

I plan to eventually remove my huge propane tank and add another 150 gal of fuel so I will not need to fill in California ever I hope.

Having seen fuel spills and having slipped and fell due to diesel fuel spills please play it safe and fill at level.

Bill767 · 10-23-2021, 05:22 AM

I have air leveling so it is very easy to tilt the coach. I always tilt and get another 10-20 gallons in, but 30, wow. As far as safety no comment, both my fillers seal very well and I am sure the fuel is sloshing over the caps constantly.

Mit12 · 10-23-2021, 10:24 AM

The fuel inlet pipes come straight out and leaves about 4 inches to the top of the tank. I am going to cut them and angle them up so that I can top the tank off. I am guessing that that 4 inches of fuel would be 15 to 20 gallons.

RoadTrip2084 · 10-24-2021, 12:36 PM

In the manual for my 97 Monaco Dynasty, it says:

Quote:

Note On Tank Capacities: The engine fuel system pumps more fuel to the engine than is needed, and the unused fuel is returned to the tank. The fuel is heated by the engine and when it returns to the tank it expands and foams. All fuel tanks are engineered to allow for thermal expansion of the fuel, and for foaming.

Monaco's fuel tanks also have flat bottoms to more efficiently utilize the available space, therefore the pickup tube cannot draw all the fuel from the tank. For these reasons the usable capacity of the tank will be less than the rated capacity, which is based on total interior volume. The actual usable capacity will be approximately 35 gallons less than the rated volume for any given fuel tank.

So it would seem that completely filling the tank is asking for trouble, no?

Twomed · 10-24-2021, 04:36 PM

Friend did this then parked after a short trip...summer temps, fuel expanded, made quite a mess. You do know there is a vent in the to of the tank.

MSHappyCampers · 10-24-2021, 05:09 PM

Do fuel tanks have vents like holding tanks? If so, would a clogged vent cause this problem?

Mit12 · 10-24-2021, 10:42 PM

I would never completely top off my tank to park it, but having 25 extra gallons during a trip would be nice. As for fuel system heating fuel and expanding I do not believe it would be an issue. I average about 7 mpg and my tank is supposed to hold 100 gallons. By the time the warm fuel from the pump could change the total temperature of the fuel in the tank I would have used a few gallons so thermal expansion of the fuel should not be an issue.