Gas leak when I fill my tank?

CANDO1

MEMBER
2008 CADILLAC STS
3.6L
6 CYL
4WD
AUTOMATIC
170,000 MILES

I have a gas leak when I fill my tank all the way up. The gasket where the hose connects to the gas tank is where I'm sure it is leaking at. I had a bad habit of topping off the gas when the prices were going crazy and that's what I believe may have caused it to leak. Can you send instructions on how to drop that tank and replace that gasket with pictures. Thats one I never had to do before
Thanks

Wednesday, March 5th, 2025 AT 12:37 PM

1 Reply

STEVE W.

MECHANIC
14,042 POSTS

If it's the filler neck that is leaking, it can be repaired without dropping the tank. Which is a good thing on that vehicle as tank removal on that vehicle requires dropping the exhaust, and the entire rear suspension out and without a lift handy is not fun. For the filler neck you remove the three screws around the top where the cap goes. Then remove the rear tire and the plastic liner behind it. You will see the filler tube in the channel. Remove the upper bolt and loosen the clamp and it will come apart. Replace the rubber tube with a new one. Reverse the process to install it. Test for leaks.

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