Fuel tanks

[tcjpfour]

I purchased a Dynamax 32KD. It has 100 gallon fuel tank which will fill only to a certain point (not even half full) then you must "trickle" in the diesel. To fill it from 1/2 full to almost full yesterday, it took 45 minutes. This is annoying not only to me, but to other service station customers. Not only that, but am I (a 78 year old woman) going to be happy standing out in the cold/wind/rain for an hour, trickling diesel fuel into the fuel tank? I think not. What is the problem and how do I fix it so that I can fuel up the MH in a timely manner? I tried removing the fuel tank cap on the opposite side, but the improvement was negligible.

 

[Wemustrv]

Welcome to RVforums from Ely Iowa. Have you tried to adjust how far in the filler tube you place the pump? Also are you fueling at the auto pumps or truck pumps? Try using the truck pumps and dual fill pumps.

 

[Kevin D Pem]

I'm watching.

 

[tcjpfour]

I've tried both auto and truck pumps. Same problem on either one. No, I have not tried filling from both sides, but will do so next time I'm out and need fuel. I've written to Dynamax about the problem and will share their answer if/when it arrives. A trucker told me it was because that when filling, the fuel level has to equalize between the tanks. That makes sense, but regardless there should be a way to fill faster.

 

[MemoriesByTheMile]

Sounds like you have saddle tanks, one on each side that you can fill.
In the truck lanes I activate the pump on the drivers side at a slower speed, then walk around to the passenger side, remove the fuel cap on that side and use the “satellite” pump to fill the passenger side at high speed. Once it is done I return that satellite nozzle back to the pump, put the fuel cap back on the passenger side and walk around to the driver side. Usually the driver side is getting close to full and within a minute it is complete. Total time for adding a total 60-80 gallons into our saddle tanks that hold a usable 120 is roughly 4 to 5 minutes. (Plus a couple extra minutes when getting DEF)

Saddle tanks can be more walking/work but result in a faster overall fill, if you fill from both sides at the same time.

 

[newmarokie]

Everything Memories said is spot on. A couple of details. There is a small line running between the tanks. It is adequate for equalizing the tanks but not for filling from one side. The excess fuel return from the engine runs into the passenger tank on most trucks. You should notice the fuel gauge come up after you have shut the engine off for several hours. The fuel gauge, unless it has dual gauges is usually on the driver side tank. I have a friend that has a Dynamax 34 and he will drive until he certain he is about to run out of fuel and the tanks will hold about sixty gallons (twin fifty gallon tanks). Trucks with dual tanks have been this way for decades.

 

[DennisT]

As stated you need to fill from both sides.

Equalizing line is not large enough to do from one side quickly.

We use 90 gallons for full on our coach based on where the fill caps are.

 

[tcjpfour]

I purchased a Dynamax 32KD. It has 100 gallon fuel tank which will fill only to a certain point (not even half full) then you must "trickle" in the diesel. To fill it from 1/2 full to almost full yesterday, it took 45 minutes. This is annoying not only to me, but to other service station customers. Not only that, but am I (a 78 year old woman) going to be happy standing out in the cold/wind/rain for an hour, trickling diesel fuel into the fuel tank? I think not. What is the problem and how do I fix it so that I can fuel up the MH in a timely manner? I tried removing the fuel tank cap on the opposite side, but the improvement was negligible.

I purchased a Dynamax 32KD. It has 100 gallon fuel tank which will fill only to a certain point (not even half full) then you must "trickle" in the diesel. To fill it from 1/2 full to almost full yesterday, it took 45 minutes. This is annoying not only to me, but to other service station customers. Not only that, but am I (a 78 year old woman) going to be happy standing out in the cold/wind/rain for an hour, trickling diesel fuel into the fuel tank? I think not. What is the problem and how do I fix it so that I can fuel up the MH in a timely manner? I tried removing the fuel tank cap on the opposite side, but the improvement was negligible.

Update 11/3/2025. Thank you members for the good advice and input. I was told by Dynamax that this was a Frieightliner problem, and it is under waranty, so I took it to the Freightliner shop. Just picked the 32KD up from the shop. Was told that there was a defective valve, and that it had been replaced. Won't be back on the road again until the middle of this month, so I won't be adding any fuel until then. I will advise if indeed that has stopped the problem. Until safe and happy trails to you all.