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Attention to those replacing the cheap, plastic fuel cover

NewRamGuy

NewRamGuy

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This is a warning to all of you using gravity-fed, auxiliary fuel tanks (specifically hot shot and RV haulers):
I have to admit seeing the cheap plastic fuel-fill cover on my ‘21 3500 made me shake my head in disgust. Really Chrysler, on a $70K plus truck, really? So I set out to find one of those anodized aluminum covers advertised almost everywhere. I ended up purchasing one on Amazon specifically designed for the ‘19 to present trucks. ‘18 and below had their own model.
I loved the way it locked in place keeping fuel in (or so I thought) and everything else out. It worked fine…until I filled the 91 gallon auxiliary tank mounted in the bed, or tried to.
It turned out the neck of the aluminum fuel cap protruded into the fill spout depressing the convex, metal cap allowing fuel from the auxiliary tank to spill out on the ground.
After trying to figure out what had happened and why diesel fuel was still pouring out even after I hung up the hose I reached into the bed and shut off the petcock to the auxiliary tank. The fuel immediately stopped flowing. By this time there was a semi behind me in line at the truck stop where all this drama occurred. I pulled out and parked in a spot and began to examine everything.
My findings were this: without the auxiliary tank (or with the tank valve in the off position) the aftermarket cap works just fine, even though it ‘opens’ the convex metal seal. The aluminum cap becomes the ‘seal.’
Now I’m back using that cheap plastic cap. Lesson learned…the hard way.
 
Maybe you should try the metal diesel caps for the previous model rams?

I just bought one the other day and after reading through all the Amazon reviews I ended up getting the same one you have for the newer Gen trucks.

That being said it seems like the other style caps will work on the newer style trucks. My buddy has a 2019 2500 And he has one of the older style caps and he doesn’t have any issues with it staying on.
 
iflyskyhigh said:
Maybe you should try the metal diesel caps for the previous model rams?

I just bought one the other day and after reading through all the Amazon reviews I ended up getting the same one you have for the newer Gen trucks.

That being said it seems like the other style caps will work on the newer style trucks. My buddy has a 2019 2500 And he has one of the older style caps and he doesn’t have any issues with it staying on.
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Thanks. Definitely worth looking into.
 
CdnHO said:
The locking cap from Geno's Garage does not contact the spring loaded sealing cap. Pricey but well made and secure.
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Just went out and looked at mine. It's for sure contacting the spring loaded cover.

The Geno's locking cap specifically says it won't work with the 2019 newer HD trucks.

He has a 2019 and newer cap for $29.95. I wonder if it comes into contact with the spring loaded cover inside the neck? By the time you pay shipping and tax it's like $45. I paid a little over $40 for the diesel and def cap combo on amazon.

The amazon parts are quality parts and fit perfect. Do I need to worry about the cap pressing open the spring loaded cover?????
 
iflyskyhigh said:
Just went out and looked at mine. It's for sure contacting the spring loaded cover.

The Geno's locking cap specifically says it won't work with the 2019 newer HD trucks.

He has a 2019 and newer cap for $29.95. I wonder if it comes into contact with the spring loaded cover inside the neck? By the time you pay shipping and tax it's like $45. I paid a little over $40 for the diesel and def cap combo on amazon.

The amazon parts are quality parts and fit perfect. Do I need to worry about the cap pressing open the spring loaded cover?????
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Only if you’re using a gravity-feed, auxiliary tank. If your truck is factory tank only…no worries.
 
If you’re replacing the existing OE tank, then no. My auxiliary tank is mounted in the bed very close to the front. The fuel line from the tank passes through a hole (approximately 3” diameter) in the bed and attaches directly to the fuel-fill spout. The only control (if you call it that) is an in-line petcock to open/close fuel flow. There’s no pump to flow the fuel, just gravity.
 
Are we talking about the green cheap plastic shipping plug? It's a capless system. They was never meant to be used other than shipping it to dealer.

It's cheap because it was meant to go in the garbage.
 
406Linetrash said:
Are we talking about the green cheap plastic shipping plug? It's a capless system. They was never meant to be used other than shipping it to dealer.

It's cheap because it was meant to go in the garbage.
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My 2011 F150 was a cap less system and never thought twice about it. Never had an issue.

This is my first diesel. Not sure where I got the idea, but I was under the impression that diesels were much more susceptible to things like water and other contaminants.

Now that I say it out loud I guess any engine is not gonna fo well with contamination. Not sure why a diesel would be any different?

I think I may have fallen into the “I saw everyone else doing it and figured I should too”?

I’m guessing if they designed it to be cap less they probably thought about the possibility of contamination, and it’s still went ahead with a cap less design so it must be okay?

But then again they went with the UConnect 5 systems so I am skeptical of their judgment….
 
iflyskyhigh said:
My 2011 F150 was a cap less system and never thought twice about it. Never had an issue.

This is my first diesel. Not sure where I got the idea, but I was under the impression that diesels were much more susceptible to things like water and other contaminants.

Now that I say I it out loud I guess any engine is not gonna fo well with contamination. Not sure why a diesel would be any different?

I think I may have fallen into the “I saw everyone else doing it and figured I should too”?
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I can understand that logic. It is more susceptible to fuel damage. But the cap doesn't make a difference. There are two doors in the neck. Even if water got in the system there is a hole above the second door to drain it out. It also has two filters in the fuel system itself. I wouldn't worry about it.

I can also tell you I put over 100k each on two Cummins with no fuel cap and no problems. Dealing with dust rain snow and everything else.
 
406Linetrash said:
I can understand that logic. It is more susceptible to fuel damage. But the cap doesn't make a difference. There are two doors in the neck. Even if water got in the system there is a hole above the second door to drain it out. It also has two filters in the fuel system itself. I wouldn't worry about it.

I can also tell you I put over 100k each on two Cummins with no fuel cap and no problems. Dealing with dust rain snow and everything else.
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I almost wonder if it’s doing more harm than good pushing that first door open? Either way that does it. Sending the cap back to Amazon. I’m sure I don’t need the fancy def cap either. And I’m also sure I can put that $45 towards diesel.
 
There is no need for a cap if you are using a gravity feed tank you need the RDS float valve that goes in the filler neck otherwise you risk having fuel come out of your vent hose aswell as the filler neck
 
NewRamGuy said:
If you’re replacing the existing OE tank, then no. My auxiliary tank is mounted in the bed very close to the front. The fuel line from the tank passes through a hole (approximately 3” diameter) in the bed and attaches directly to the fuel-fill spout. The only control (if you call it that) is an in-line petcock to open/close fuel flow. There’s no pump to flow the fuel, just gravity.
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you have to use the RDS float valve that goes inline on the filler neck anything else is improper and you will overflow out of the vent and the filler neck

My aux tank has no issues with no filler cap….
 
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