Major fuel leak from gas tank - Toyota Nation Forum : Toyota Car and Truck Forums

sljorge · 04-29-2009, 04:55 AM

So I failed my emissions evap pressure test today. I figured this might happen: Ever since I bought this car in July '07, whenever I top off the gas, I smell very strong gasoline odor.

So now I have to address it. I first looked at the filler pipe and found nothing. Then I noticed a pool of gas on the ground under the right front corner of the fuel tank! I guess this might be the problem.

I jacked up the right side of the car and found this:

So the leak/smell only shows up when I top off the tank. And tonight it started dripping onto the ground when I jacked the car up from the left side. It stopped dripping when the car was flat or when I jacked it up from the right side.

I remember seeing drops coming off the shroud over the exhaust which leads me to believe the leak is near center of the tank on the top. Possibly the fuel pump gasket? I'm assuming the only two holes that are SUPPOSED to be in the tank are the inlet and the fuel pump. The inlet is dry.

Any thoughts of where this is coming from or how to fix it?

-Dripping Gas in AZ

donbryce · 04-29-2009, 08:52 AM

If you can access the top of the tank from the trunk, usually a removable panel, check the top around the outlet/return inlet, and all the piping into the tank as well (evaporative lines, filler neck joins, etc.). If you're lucky, it's just a gasket or hose clamp leak. If not, it's probably a leak in the pinch-weld, where the top and bottom half of the tank are joined. It may be possible to see this with a light and mirror without dropping the tank. A weld seam leak means a new or re-manufactured tank (where they coat the tank with epoxy).

GtariSSt · 04-29-2009, 10:45 AM

This may be stating the obvious, but unless or until you fix it, don't fill it all the way. If you are experiencing no other problems, you can drive a good long time this way.

hill8570 · 04-29-2009, 11:28 AM

Quote:

Originally Posted by GtariSSt

This may be stating the obvious, but unless or until you fix it, don't fill it all the way. If you are experiencing no other problems, you can drive a good long time this way.

He failed his emissions testing due to this (well, OK, probably due to this). He's probably got a limited amount of time to fix it and get it re-inspected otherwise they do something nasty, like yank his registration.

GtariSSt · 05-01-2009, 10:52 AM

My bad. I guess I should read more thoroughly. We don't have state inspections here, thank goodness.

ghettosled · 05-01-2009, 11:05 AM

the fuel pump is access through the top of the tank. you can access this by removing the bottom cusion of the back seat, remove the screws on the access door and you will see the top of the tank and fuel pump. if that area is dry, you probably have a hole rusted through somewhere. you being in arizona, i would bank on a bad rubber seal around the fuel pump.

sljorge · 05-02-2009, 01:54 PM

So I pulled the fuel pump today and found no issues with the gasket (looked brand new after 17 yrs). I next topped of the tank again to see where the fuel is coming from and verified it is NOT coming from the fuel pump.

I did however, while looking through the fuel pump access hole, see a trickle of gasoline come rolling down the center trough from back to front on the top of the fuel tank. I could not see the source of the leak.

I'm afraid I now need to drop the fuel tank which is FULL of gasoline!!!

.

How do I drain a full tank?

How do I drop the tank?

-HELP!!!

donbryce · 05-03-2009, 03:16 PM

You could snake a piece of hose into the tank and get a suction going. I've done this, but be prepared for a nasty bit of gas in your mouth if you don't 'release' at just the right moment. Make sure the hose is long enough to reach the ground, or below the tank, and have lots of containers handy to pour it into so you don't have to stop the siphon. A drill operated pump works good too, I'm told, and I have one but never used it yet for this purpose. Other ways to get the siphon going will hopefully get submitted by readers here. You only need to drain out a little over half the tank or more, just enough so that it won't be too heavy to manage to drop it.
To remove the nearly empty tank, I'll provide the basics, good for most cars, and you can add what's peculiar to yours. Put the car on jackstands, level, and high enough to get a floor jack under the tank and enough clearance to drop the tank down and roll it out on the jack. Undo all the hose and line connections. Undo the straps at one end holding the tank to the underbody. Let it down and, balanced on the jack, roll it out from under the car. It will be very heavy, and it will want to tip as the fuel sloshes around inside. See if you can get a helper.
Now, you will likely see the source of the leak. Decision time is now: fix or replace? If it is fixable, like a pinhole, there is an epoxy 'stick' that can be used to repair the hole. It comes in a bubble package, get it at any autoparts store. To prepare the metal around the hole, first be very aware of the dangers working on a fuel tank, empty or full: ANY SPARK CAN AND WILL LIKELY CAUSE AN EXPLOSION, so drop the project NOW if you aren't brave/confident enough to do this. Tape over all the exposed holes to the tank to minimize any chance of ignition. Duct tape works good. Hand sand the area with 80 grit paper or similar to remove 95% of the rust/crud. Clean with laquer thinner or whatever, until the steel is shiny clean. Follow the instructions on the patch compound package, which probably say to cut off a piece of the stick and knead it until mixed, then apply to the hole. If the hole is too large for the compound, you might be able to drill it out and put in a pop-rivet or sheet metal screw, then apply the patching compound over that.

***96paseo*** · 05-03-2009, 08:53 PM

Buy a siphon kit and have 3 five gallon gas cans handy to drain the tank.

sljorge · 05-05-2009, 01:01 AM

Luckily, my wife's minivan was near empty. So we parked the cars such that my Camry was higher than the van and ran a 20' hose between them and drained my tank into hers.

By the way, I had to unbolt the fuel pump and run the hose from the access hole under the backseat, I could not reach liquid fuel thru the gas cap. That's good in my book...no one can siphon my tank now.

Now I get to drop the tank. Stay tuned...

sljorge · 05-07-2009, 03:21 AM

After a lot of blood, sweat and tears, I found the hole in the gas tank. After dropping the center exhaust and lowering the fuel tank, this is what I saw:

It was not obvious to me where the leak was. I looked very closely for a long time and almost gave up for the night, when out of the corner of my eye, I saw a slight bump in the surface of the tank. It didn't look like much until I cleaned it off with some carb cleaner:

I then used a wire brush attachment on my drill to find this:

Question: How does a crack like this get on TOP of the gas tank? This area is protected underneath the back seat and this spot is right underneath the rigid fuel EVAP pipe???

I next opened up the crack a bit with a dremel tool to prep for a patch (no pic). Then I put on a healthy glob of JB Qwik Weld:

Now I get to put everything back together and hopefully not have any parts or screws left over!!!

jmborchers · 05-07-2009, 07:47 AM

Does Quikweld hold up to gas? Some adhesives do, like fiberglass or epoxy resin. Others don't.

The metal probably rusted through in that location. Any water sitting on top of the tank would eat it's way through.

Secondary would be metal fatigue over time created a crack in a weak spot.

sljorge · 05-07-2009, 11:08 AM

http://www.jbweld.net/products/jbkwik.php

jmborchers · 05-07-2009, 11:21 AM

"It's water-proof, petroleum-, chemical-, and acid-resistent"

Resistent does not mean proof. The way I read this they are saying resistent to petroleum. This means it will last a short time under 100% exposure.

What you really want is a fiberglass or metal weld repair. The tank will have to be nitrogen or argon purged while welding on it even after cleaning it out.

After further looking in the FAQ I find what I was looking for:

"Q: Is J-B Weld resistant to water and/or gasoline?
A: When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical. For wet-surface or submerged water or gasoline repairs, see our J-B Stik or Waterweld product information. "

Recommend redoing the repair with the J-B Stik. Then you should be all fixed for good.

http://www.jbweld.net/products/jbstik.php

***Eye8Pussies*** · 05-07-2009, 11:54 AM

^ he makes a good point, but considering the amount of work it takes to drop the fuel tank, I'd wait until (if) it leaks again

but by the same token, I wouldn't fill the tank up all the way from now on so that the patch will be submerged in fuel either

great job dropping the fuel tank!