02 October 2019

Because The Service Manual Does Not Say

The o-rings for the fuel tank crossover pipe need to be in a certain order.

All the service manual says is:

During disassembly: "Important: Take care not to disturb the internal O-rings in the fuel tank connections."


During reassembly: "Lubricate the crossover tube to fuel tank connection O-rings (1-4) with GM p/n 1051717 (Canadian p/n 5728223) rubber lubricant."

OK, what should I do if all the two big o-rings come out of the tank with the crossover's snout?

There's no way to take care to not disturb them because you can't see what they're doing or prevent them from doing it while you're pulling the crossover out.

Today I found my answer.

I've been chasing a fuel smell since I got the car back together.  Very frustrating.

I've been blaming the fuel filler hose (p/n 15814859, unobtaniun at any price) being cracked or damaged.

Not one salvage yard separates the filler hose from the tank when they sell the tank.  I've asked too.

Luckily, JT found a local salvage place selling the whole tank (less sender assy) for about what the dealer wanted for just the filler hose and it had the hose on it.  So I snagged it!

Inspecting things I noticed that the o-rings were NOT disturbed when this tank was removed.

In order, from deepest in the hole to closest to the opening:

1.  Green o-ring.
2.  Small black plastic ring.
3.  Yellow o-ring.
4.  Large black plastic ring with inside bevel.


I didn't have mine in that order because they all jumbled out and were dangling from the jet-pipes.

The order I have mine in is:

1.  Green o-ring.
2.  Yellow o-ring.
3.  Small black plastic ring.
4.  Large black plastic ring with inside bevel.

Wanna bet that's where my smell is coming from because those o-rings aren't sealed without the small ring to spacer them?


Probably have to drop the tank to get at them properly.


  1. And now the proper sequence IS documented. Because you´re better at this than the people who get paid to do it.

  2. Is the new tank same as old? Just replace the whole unit, unless of course that requires disassembly of half the car (again).

    I realize it is a Vette and those are iconic, so you deal with it and fix it.

    I left GM after the 3.8 engine series of cars and vans that were no end of trouble, then the German mish-mash called Saturn L300, where the V6 engine was fantastic (between gas stations - damned thing could hold it's own to a muscle car) but it had so many electrical gremlins towards the 10 year mark that I gave up and traded it in.

    1. The new-to-me tank is from a 2005 and while a different part number, they are interchangeable.

      Swapping the tanks means extracting the fuel pump/sender assembly from the old tank. Ick.

      Getting the tank out without taking apart half the car looks doable, but irritating.

      I'm going to inspect every thing that could be leaking, but the prime suspect is one or both the crossover o-rings have gotten kinked by having them in the wrong order. Next most likely is the filler hose is cracked or ripped. It's possible it's the pump/sender flange o-ring too. Least likely is a cracked tank, but it's been known to happen.

  3. In the famous words of a has been pol, "I feel your pain". Best of luck with finding the cause, may it be a simple fix and Murphy be far, far away.


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