I need some thoughts on a gas tank issues that has cropped up recently with my Legacy. I swear my car has decided to fall apart on it’s 11th birthday :/ Anyway, back to the issue. I’ve started to smell gas after I fill my car up and it persists until the tank goes down past the ¾ or ½ mark. Originally I thought it was coming from the front of the car abut it’s actually the back at the tank. I do not notice any puddles under the car or any ‘dripping’ when I look for an extended period. What I did find was gassy smelling condensation with a small drop holding on to the seam at the bottom of the tank on both the drivers and passenger side.

Any thoughts? Is this tank rot or could it be something else? I’m not going to be able to fix this on my own, but I would like to be able to locate exactly what is going on so I can take my car in to be fixed without being ‘taken for a ride’ by the mechanics. I don;t want them to tell me I need a whole new tank when it might just be a seal somewhere.

Thanks!

Urban Coyote

Hm, well often the fuel filler necks rust out so it might be coming from there. But there are also many other little lines and stuff under there for evaporative emissions so maybe something is rusted out with those.

Sorry, I should have mentioned that the filler neck was replaced two years ago. There also doesn't 'seem' to be much effect on gas mileage that I've noticed.

 

I'm curious about "little lines and stuff under there for evaporative emissions". Can you check on them from the trunk or back seat if you pull up the carpet inside the car? What's the best way to go about "looking around" to get an idea of what might truely be happening?

 

Urban Coyote

You can see all the little lines and stuff under there from under the car. The specifics vary if you have the evap canister under the hood or if it is under the vehicle near the tank.

 

If you can't find the leak a shop with an evap test smoke machine should be able to find it.

 

This is a pretty good article about some of the plumbing in there: Evaporative System Diagnosis http://endwrench.com/images/pdfs/EvapSpring04.pdf

Urban Coyote,

To track down your leak I believe you'll be forced to drop the gas tank from the car. Once down you'll be able to see where the problem is. I work in an antique auto restoration shop, and more times than not, gas tank leaks can only be diagnosed and fixed after the tank has been dropped. Good Luck!

I have the same issue on 98 Legacy L: Gas seems to be slowly disappearing.

Sorry, I should have mentioned that the filler neck was replaced two years ago. There also doesn't 'seem' to be much effect on gas mileage that I've noticed.

 

I'm curious about "little lines and stuff under there for evaporative emissions". Can you check on them from the trunk or back seat if you pull up the carpet inside the car? What's the best way to go about "looking around" to get an idea of what might truely be happening?

 

Urban Coyote

 

 

Pull up the floor, you will notice two metal plates on either side of the car behind the seat. Unbolt those plates and you will have access to the lines.

 

 

nipper

Thanks porcupine73. I went to read the article but I don't think it will help me a whole lot as my Legacy is a 98 and the article mentions that Subaru only started putting the vapor recovery system in it's cars in 2000.

 

Thanks nipper! I will try to take a look in the next day or so.

 

I priced up a replacement tank and work from a local garage and they said between $800-1200 CAD I realize it's a lot of work to get the darn thing out to replace, but WOW!

 

I filled the tank this morning to about 2/3 and didn't notice any major gas smell when I got to work, but I will check again when I leave to see if anything has changed.

 

Etc looks like we're both in the same situation, you have exactly the same car as mine.

 

UC

Soobs back into the mid 90's and maybe earlier have the fuel vapor recovery. It just depends if you have the older style with the canister under the hood, or the later enhanced evap setup with the canister underneath by the tank.

 

Anyway the evap smoke test machine is probably going to be the easiest way to find the source of the leak.

 

Here's a pic of those portals with access to the lines:

 

I have been noticing a fuel disappearing problem in my soobs too, it seems to lose a couple gallons during the trip to work and home.