How low can the fuel level be and still safely operate a Monaco diesel pusher?

[Guest Ray Davis]

IMHO trying to travel as far as you can between filling up is flirting with disaster.  With low fuel even the lean of the road could cause it to suck air and it doesn't care where you are.  When I ran out we were off the road but leaning mightly.  I knew it's going to need quite a bit of fuel in the tank to ever pick up so I went down the road, bought 2 gas cans, filled them up twice. ( 20 gals ) That's not fun especially for old guys plus it was really hot.   Even with that much fuel I didn't think it was going to start.   I saved a little fuel so I replaced both filters and prefilled them, cycled the lift pump for what seemed like forever then it finally started.  I was wishing I had installed a Fass fuel pump , still might.  I hope to never go through that ordeal again.   My message is it may not start right up like your car probably does and you may need quite a bit of fuel depending on how the coach is sitting.                  Gas cans are even expensive now, I think those cans cost me something like $35 each, no time to shop around,   Another part of my bitter lesson.

Edited August 15, 2022 by Ray Davis

[Tom Cherry]

12 hours ago, jacwjames said:

Hmmm

My brochure says 128 gallon tank, which is what I set my tank minder on the Silverleaf at.

I just checked my manual and it says 118 gallon tank. 

Scary since I have pumped 100 gallons into the tank.  Will have to rethink that and start targeting 90 gallon max consumed.

Use David’s formula.  I’d give the brochure the “edge” as the marketing folks were probably better the the laggards that were updating the manuals.

MY COMMENTS ON PUSHING A PUSHER.  DO NOT.  With 67K and being the original owner, I would use 75.  I use 75 and have a 135 (both sources).  I use Gas Buddy and plan my fuel stops based on cost and “ease” of entry/exit.  All the chatter here says, plus many years of debate on the old site, that even in the same model year, Monaco was not consistent in the engine or Genny fuel pick up lengths.  
 

I pick out a fill up, price and where I will be, using the 75 gallon max rule.  I then do a Google earth view or a street level view so I can get in.  Obviously the big brand truck stops will be ok, but I have found up to a $0.15 difference in a truck stop and a large convenience mart at the next exit…one with only one dedicated lane or maybe 2….but rarely mixed in with the gas.  Now, I violate my rule locally as I have a stop up the road from storage and the 2 diesel only pumps always gave traffic, so I know the fuel is being turned over.

I personally do not want to have to contend with air in my Genny or the Engine.  I know folks that will do mega miles per day…and my hat and body is off to them.  But, for me, the 75 rule works and I save quite a bit on fuel.

[cbr046]

3 hours ago, Tom Cherry said:

 . . . .  the big brand truck stops will be ok, but I have found up to a $0.15 difference in a truck stop and a large convenience mart at the next exit…one with only one dedicated lane or maybe 2….but rarely mixed in with the gas. 

Is that using a TSD card? 

I've found Buc-ee's to be very competitive with Sam's Club / Costco and truck stops using TSD card.  Buc-ee's has lots of pumps (200+) and room to get in & out, but not that many locations.  So far I've got Northwest, South and West covered but nothing Southwest or Northeast (yet).  https://buc-ees.com/

- bob

[Tom Cherry]

10 minutes ago, cbr046 said:

Is that using a TSD card? 

I've found Buc-ee's to be very competitive with Sam's Club / Costco and truck stops using TSD card.  Buc-ee's has lots of pumps (200+) and room to get in & out, but not that many locations.  So far I've got Northwest, South and West covered but nothing Southwest or Northeast (yet).  https://buc-ees.com/

- bob

Nope.  Gas buddy app.  I use a Costco card as they give me a 4% rebate.  

[cbr046]

21 minutes ago, Tom Cherry said:

Nope.  Gas buddy app.  I use a Costco card as they give me a 4% rebate.  

Have you looked into the TSD program?  https://myopenroads.com/

T/A up the road (Commerce GA) showing $4.71 pump price (nobody pays that) but through TSD it's $4.09 (+10% x (4.71-4.09) + 65c).  So if I bought 50g cost would be $205.21 or $4.104 / gal.  PLUS you don't have to wait all day squeezing a Costco pump handle (not to mention waiting in line).  My local Sam's Club (I have no idea where Costco is locally) is $4.23.  If I took a 4% rebate my 50g would cost $203.04, or $4.06 / gal.  You win but in this scenario not by much!  And getting in / out of that Sam's Club is "challenging" and I still don't like waiting forever and ever to pump fuel.  I'll pay the 4c / gal premium for ease of access and fast pump.

So what card gives a 4% rebate on fuel?  My "accountant" wants to know.  😁

I'll throw this out there . . . . When using Gas Buddy they want to track me and share my data with their "trusted partners" every time I open the app.  There's no way to opt-out of this "service".  There is a work around, but if I'm going down the road it's very difficult to read and hit all the right buttons.  Then when finally getting to a gas map there's ads I have to dodge so I don't accidentally bring up some product / service I have no interest in.  These 3 paragraphs could be split into a new topic . . . .

- bob

[jacwjames]

OK, out of curiosity I went ahead and measured the size of my tank.

Allowing for 1/4" thick metal the measurements were

Length  88.5"

Width  20.5"

Height 17.5"  This was to the top of the neck, highest point for fuel without tilting rig or having fuel burp all over me.

So the volume is 31,750/231 cuin per gallon = 137 gallon

My tank angles in at the top so I figured I lost 21.5 X 9 X 3" of volume  2.5 gallon >>>>  so total fuel in tank =~ 134.5 gallon.

I tried to remove my pickup tube but it is ~5/8" stainless tubing and I didn't have enough headroom and did not want to try and bend it.  So I got a little creative and pulled it out as far is it would go, ~11".   I then cut a piece of copper wire and bent both end 90 degree opposite of each other one about 2" long, I ran this down beside my pickup tube with the longer end against the tube and I was able to tell how far the  tube was still sticking into the tank, I came up with tube length of ~16" meaning there was still 3" of space on the bottom  so (88.5X20.5X3)/231=23.5 gallon of fuel.  The tube might stick down a little further since I didn't allow for the threads on the fitting into the tank which are about 1". 

So if I do have 134.5-23.5=111gallon of usable fuel  less some sort of safety factor.  I had been using 100 gallon, I may start using 90.   I normally start looking for fuel at a half a tank but on occasion will run further.  On my last trip I pushed on the last leg home and pumped right at 100 gallons. won't be doing that any more. 

 

Only think not sure of is I've read that there are baffles in the tank, not sure of the design and whether they may help or hurt.

[Guest Ray Davis]

2 hours ago, jacwjames said:

Only think not sure of is I've read that there are baffles in the tank, not sure of the design and whether they may help or hurt.

My tank has baffles I can see one when I look down the filler pipe with a flash light. 

For the most part baffles are good but I wanted to put an old time fuel sender with a long swing arm / float but a baffle was in the way.

[Frank McElroy]

There is a good reason why you don't want your fuel tank to get too low.  A few years ago I was between 1/8 to 1/4 tank on the gauge.  My gauge sensor is an Isspro with reed switches.  I know it's accurate - I confirmed it. 

The problem was when on a high bank exit ramp in Texas with stopped traffic the coach was leaning so far over to the drivers side that the gauge read below empty.  We were at a near dead stop with very slowly creeping traffic.  The coach still ran but I was almost ready to go into manual level mode to compensate for the high bank and tilt the coach to the passenger side to not run out of fuel for the engine.  What I don't know is if my fuel tank has an internal baffle to keep some fuel around the engine fuel pickup tube and for how long when tilted but not driving. 

I got lucky - the engine never stopped.  I learned a lesson - 1/4 tank fuel is my limit on how low I'll go.

[cbr046]

Not to mention all the crud in the very bottom of the tank.  When I ran out I walked and got 7 gal of (very heavy) fuel, drove 1/2 mile, got another 5 gal of fuel, drove another 1/2 mile then ran out a third time on level pavement . . . . . I found changing the primary filter was the magic to get me the rest of the few hundred feet to the pump. 

BTW, changing a primary filter in the left turn lane of a no shoulder two-lane road with my butt hanging out is not something I want to repeat.  When a vehicle approached I'd have to pull out, close the panel and step behind the coach to let them by.  Fortunately 18-wheelers make a lot of noise. 

Some time later installed a FASS system.  I'm amazed I haven't needed to change that filter yet, especially being it's a 1.4um filter.  I guess I sucked up all the crud in that one incident.

- bob

[ok-rver]

I posted a few days ago I was going to drain my tank and check levels that gen and engine shut off, 2004 Holiday Rambler Scepter, calculated 95 gal to bottom of fill tubes. Started at just over a 1/4 tank. Generator shut off at just below 1/4 tank. Calculated 8.5 gallons removed. Started sucking air after pumping out another 21.5 gals. Gage showed empty. Tilted to driver side 2" lower than passenger and pumped out another 3 gals.  Will drive to Costco for fill up later this week and see how much more it will hold. 

A little over 6,000 miles on 1st set of FASS filters. Pressure at idle had dropped from 19 psi originally to 15ish psi. Replaced filters after fuel was back in tank and pressure is back to around 19 psi. Diesel in drum was clear enough to see hose at bottom of drum with 19" of diesel. FASS filters doing a great job in keeping things clean.

[DZZippy]

This is a great topic and I’m interested for sure. All relevant info so thanks to all. Curious though, has anyone actually seen / measured the fuel pick up tube (engine) to see what the actual depth is in the tank? 

Edited August 17, 2022 by DZZippy

[jacwjames]

16 minutes ago, DZZippy said:

This is a great topic and I’m interested for sure. All relevant info so thanks to all. Curious though, has anyone actually seen / measured the fuel pick up tube (engine) to see what the actual depth is in the tank? 

I tried to pull my pick up tube on Monday but it's too long, so I got creative and used a piece of copper wire to try and figure out the length.  See my post above.

Best I can tell it is at least 16" long, possibly a little longer. 

[cbr046]

17 minutes ago, DZZippy said:

. . . .  has anyone actually seen / measured the fuel pick up tube (engine) to see what the actual depth is in the tank? 

Given previous comments about Monaco consistency over the years every fuel pickup could be different.

- bob

[DZZippy]

1 minute ago, jacwjames said:

I tried to pull my pick up tube on Monday but it's too long, so I got creative and used a piece of copper wire to try and figure out the length.  See my post above.

Best I can tell it is at least 16" long, possibly a little longer. 

Thank you!

1 minute ago, cbr046 said:

Given previous comments about Monaco consistency over the years every fuel pickup could be different.

- bob

That is for sure…could have two identical coaches going down the line at the same time with different results. Definitely food for thought.

[Cristian]

I also don t trust the fuel gauge and try to stay around 1/2 tank and also keep track of mile per gallon ....

[jacwjames]

9 minutes ago, Cristian said:

I also don t trust the fuel gauge and try to stay around 1/2 tank and also keep track of mile per gallon ....

I use a Silverleaf VMSpc monitoring system.  Very accurate as far as fuel consumption. 

[Dr4Film]

25 minutes ago, jacwjames said:

I use a Silverleaf VMSpc monitoring system.  Very accurate as far as fuel consumption. 

That's what I have been using since 2010 on the Windsor then switched it over to the Dynasty we own now.

Won't drive a coach without it. Love the VERY accurate information versus the analog gauges that you have to peer over the steering wheel just to see the important ones. I will use the large Tach and Speedometer occasionally but rely on the VMSpc 99% of the time.

[jacwjames]

1 minute ago, Dr4Film said:

That's what I have been using since 2010 on the Windsor then switched it over to the Dynasty we own now.

Won't drive a coach without it. Love the VERY accurate information versus the analog gauges that you have to peer over the steering wheel just to see the important ones. I will use the large Tach and Speedometer occasionally but rely on the VMSpc 99% of the time.

So Monday I decided to start the coach and move it so I could do some work on it.  The fuel gauge read 1/2 full but I knew it was full

When I was measuring my pickup tube and removed the fuel cap the fuel was almost high enough to spill out,  

That's why I don't rely on the fuel gauge.

[Guest Ray Davis]

You would think that consistancy in these coaches would have made building them easier and faster.                        I don't get it,  but it doesn't seem to impact quality.  Monaco built a top notch coach.

I can just imagine a worker stepping over to a chop saw and cutting a fuel pick up tube, eye balling it saying that looks pretty close.  It's like a bin of precisely cut pick up tubes never occured to anyone.   

Tom, why wasn't you there?   Monaco might still be around.

Off Topic,                                                                                                                                                                          I have a friend that owns a Hyundai,  his gas gauge quit long ago,  he is so tight he squeeks when he walks, so he keeps track of mileage which works fine until he forgets.  That almost causes him to get it fixed, but not quite yet.    This same car V6 started running bad so he took it to the Hyundai dealer.  The dealer hooked up their computer and said you need 2 coils, 2 injectors and 6 plugs, well guess what, no improvment, so its gotta be the catalytic converter that'll be another $1900 but we don't have one.  Take it down the road to the little shop where it won't cost so much. The little shop says no can help, try another, and another, and another no one will even look at it. The car has the plague.  Is the word out don't touch V6 Hyundai's?  I thought it was a pretty good car.

IIRC it's a 2012 

 

[RIPPPA]

I have a 2005 Dynasty with a 150 Gallon tank. I would never go below 1/4 tank. On our last trip my fuel gauge crapped out the first night so I started counting mileage and figured I can travel 825-900 miles on a full tank so I started stopping every 500 miles to be safe and could go to 600 miles if needed before fill up. That’s 8-10 hrs of driving and I’m ready to stretch my legs by then anyway. We drive a lot from North Texas to Western Colorado.  

[RoadTripper2084]

For me so far the closest to empty I've gotten was a hair below 1/4, with the low fuel light solidly lit. It took 88 gals into my 130gal tank to fill to the bottom of the fill tube opening. I figure I might have had 5 or maybe 10 gallons useable left, or less if I had to park on an uphill, etc.

 

 

 

[WCourand]

On a trip to Las Vegas last year,  we ran very low for me, to the 1/8 mark on the fuel gauge.  Pulled into the T/A and filled the tank with 128 gallons for a 150 gallon tank.  So with that info I guess the fuel gauge is fairly accurate.  Sure hate to get into that area of the fuel gauge.

[Dbircky]

Last trip put 127 gallons in my allegedly 130 gallon tank.   The generator was still running too.   I do drop the right side and lift the left side when filling from the left.  Is there a way to have the fuel used display more than 99 gallons?   

[jacwjames]

3 minutes ago, Dbircky said:

Last trip put 127 gallons in my allegedly 130 gallon tank.   The generator was still running too.   I do drop the right side and lift the left side when filling from the left.  Is there a way to have the fuel used display more than 99 gallons?   

You are a very brave person.  You must have been running on fumes.

I thought I was pushing it when I'd use 100 gallon out of my 128 gallon tank.

[RIPPPA]

I don’t trust the gauge. My gauge stopped working after 100 miles on our last trip so I started figuring mileage. I found out I’m getting around 5.7 mpg and with my 150 gallon tank I start looking for a truck stop at 600 miles. That gives my a 250 mile buffer. 
It’s easy. I just save my mileage at the start and every fill up on my phone and carry on.