Which way does the filler tube seal install?

*** Follow-up at bottom of thread ***

I got this improved design gas tube seal. Did a search and found answers indicating both directions?

So does the rounded side face out or inside of the tank?



Thx

I'd put the rounded facing out. Flat side to the tank

Call the manufacturer and ask them Please post what you find out on here so more people will know from your findings

Is there a directional lip inside? If so I would install it with it pointing inside, sorta like a front or rear main seal.

Saved this when I bought mine.

Just like 71rm23 said, flat side against the tank.

On mine I had the flat side outside, now sure (now) if that is correct but it did fit/no leaks.

X3

Thx for the replies, my plan is to:

- install grommet in tank, round lip out (no RTV or sealer needed?)
- install the rubber floor pan gasket on filler tube (Challenger)
- partially install tank with straps, let it hang down
- slide tube down through floor pan into tank, lubed grommet with silicon beforehand
- tighten up straps holding tank
- pull tube back up to mount to qtr panel

Sound right?

Same here. Several hard launches and never leaked a drop of fuel. Thought it acted like a baffle and it kept pressure off the "main" seal.

DMT (manufacturer of the seal) responded to my question:

"The rounded side goes into the tank"

Now I'm confused, what's right?

This might actually makes more sense, extra seal area inside tank.

6 of one, half dozen of the other.

Install the neck to car and and the boot to the trunk floor then grease up the seal and slide the gas tank on . It usually doesn't work to good putting the tank in first . And the round side of the seal goes in as there is a bevel on the other side to help start the neck in.

I'm not sure about this particular seal but look at the lips on the ID. Which way would the filler neck slide in the easiest? That's typically the way the seal is installed. As a comment, the FSM for the later rides recommends using power steering fluid as an assembly lube and that's what I've used in the past.

Follow-up:

Right or wrong, I'm installing it with rounded side in for 3 reasons

1) Stock tank is installed that way. May have been replaced over the years, but factory PN is on flat side, seems logical they would want this visible
2) Flat side has beveled opening, easier to insert tube without damaging seal
3) Rounded side has smaller opening, this is the extra sealing from earlier design, seems extra seal should be inside tank, not outside after a leak of primary seal

Makes perfect sense to me.