Fuel leak when full, no cel. (1 Viewer)

Joined
May 18, 2018
Messages
1
Location
CT USA
My first post, been lurking for a while but I haven't seen another post on my issue.
When the fuel tank is full it leaks from somewhere on the top of the tank.
Truck has very little rust, so I don't think that is a factor.
I was prepared to drop the tank and check everything out and if need be get a new tank and be done with it.
Took it to my buddies shop to do it but first he did a smoke test, and nothing we were kinda pressed for time so I said forget it we'll tackle it another day. That was 2yrs ago. So I'm confused.
I am assuming any condition where I would have a leak would throw at least a evap system cel??
But no cel, no pending cel, passed emissions test with flying colors and has been doing it since I bought it 3 years ago..
I just fill it to 20 gallons and have no issue. Got used to doing that but now I am wanting to get to the bottom of this...
Anybody?
 

blinder52

SILVER Star
Joined
Aug 18, 2020
Messages
76
Location
Springfield, Missouri
I had this issue as well. I would fill the tank and the next morning there would be a fuel smell in the garage. My rig is sorta medium rusty so I’m always on the look out for things related to that. It doesn’t take more than a few drops so make quite an odor.
Finally one day I used a good light source and spotted a damp spot along the seam on the driver’s side up by the frame. I couldn’t tell it it was from the seam or had run down from on top. There are three openings that has gaskets besides the lines and main filler. Mine turned out to be the seam itself. Fuel tanks get a crazy amount of dirt and such on top over the years. Even if it looks good in the bottom, there’s no telling what going on on top. Give a really good inspection and maybe open the top hatch and look at the pump access.
Dropping the tank is not the worst job I’ve done. Actual dropping is easy... raising is tedious.

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Joined
Nov 4, 2007
Messages
10,500
Location
Colorado
I had this issue as well. I would fill the tank and the next morning there would be a fuel smell in the garage. My rig is sorta medium rusty so I’m always on the look out for things related to that. It doesn’t take more than a few drops so make quite an odor.
Finally one day I used a good light source and spotted a damp spot along the seam on the driver’s side up by the frame. I couldn’t tell it it was from the seam or had run down from on top. There are three openings that has gaskets besides the lines and main filler. Mine turned out to be the seam itself. Fuel tanks get a crazy amount of dirt and such on top over the years. Even if it looks good in the bottom, there’s no telling what going on on top. Give a really good inspection and maybe open the top hatch and look at the pump access.
Dropping the tank is not the worst job I’ve done. Actual dropping is easy... raising is tedious.

View attachment 2591893

View attachment 2591894
Looks like the prefect jack for the job.

Did you see anyway to keep gas tank in place, while just pulling the gas tank shield?
 

blinder52

SILVER Star
Joined
Aug 18, 2020
Messages
76
Location
Springfield, Missouri
Well in my case no. And actually the shield and tank come down together. That’s why I suggested looking in the pump access hatch to see if you observe anything. Of course they don’t make that easy as it’s under the carpet beneath the rear seat.
I think that my seam leak was so small that it took a day or two for fuel to make its way out after the weight of fuel above the seam line forced it out. My tank looked great inside and could probably I could have rolled some tank sealer around in there but @87warrior made me a deal I couldn’t turn down on his tank after he installed a LDT. He had a nice shield too which I needed.
 
Joined
Jan 8, 2021
Messages
21
Location
Georgia
Did you ever find the leak or cause of smell? Mine just did a lot of driving in hot traffic which it hasn’t done in a long time and all of a sudden when I get home it smells like it’s leaking but I can’t see anything.
 
Joined
Nov 4, 2007
Messages
10,500
Location
Colorado
Did you ever find the leak or cause of smell? Mine just did a lot of driving in hot traffic which it hasn’t done in a long time and all of a sudden when I get home it smells like it’s leaking but I can’t see anything.

Smell after driving may be "fuel Boiling".
Clues:
Look under gas cap cover door, in gas cap area. Is area under door dirty/gunky looking. This could be indication excessive fuel pressure building in gas tank.
Watch ECT (engine coolant temp) with OBII (dash gauge not much help, unless overheating), are you running hot.
 
Joined
Jan 8, 2021
Messages
21
Location
Georgia
Smell after driving may be "fuel Boiling".
Clues:
Look under gas cap cover door, in gas cap area. Is area under door dirty/gunky looking. This could be indication excessive fuel pressure building in gas tank.
Watch ECT (engine coolant temp) with OBII (dash gauge not much help, unless overheating), are you running hot.
No it wasn’t running hot, although I was in a lot of traffic parked at the airport and when I came back out to it after greeting my family it smelled like raw fuel but no puddle.
I have noticed after work when I get home( 20 minute drive) the rear quarter panel right by the gas door is making a deep buzzing noise that pluses. I haven’t had the vehicle long so I just assumed it was something to do with the ahc system but it’s starting to sound like the evap canister and purge valve seem to be not functioning.
 
Joined
Nov 4, 2007
Messages
10,500
Location
Colorado
No it wasn’t running hot, although I was in a lot of traffic parked at the airport and when I came back out to it after greeting my family it smelled like raw fuel but no puddle.
I have noticed after work when I get home( 20 minute drive) the rear quarter panel right by the gas door is making a deep buzzing noise that pluses. I haven’t had the vehicle long so I just assumed it was something to do with the ahc system but it’s starting to sound like the evap canister and purge valve seem to be not functioning.
Sound to me like you may very well have been running hot. The dash water temp gauge do not move much, unless overheating to dangerous level in most 100 series. A clue if you've been boiling fuel is under body door for gas cap. The area gets gunky looking, if issue been accruing for a prolonged time.

It's very good idea to list your year, mileage and area/region your 100 series spent time in. You can put this info in your signture line.

Toyota moved the charcoal canister (CC) in 03- to the rear. Very important to stop filling with gas at first auto shut-off of pump handle. Over fill damages CC.
 
Joined
Jan 8, 2021
Messages
21
Location
Georgia
Sound to me like you may very well have been running hot. The dash water temp gauge do not move much, unless overheating to dangerous level in most 100 series. A clue if you've been boiling fuel is under body door for gas cap. The area gets gunky looking, if issue been accruing for a prolonged time.

It's very good idea to list your year, mileage and area/region your 100 series spent time in. You can put this info in your signture line.

Toyota moved the charcoal canister (CC) in 03- to the rear. Very important to stop filling with gas at first auto shut-off of pump handle. Over fill damages CC.

It’s an 04, 228k. There’s no gunk it’s fairly clean and I never fill any car more than what the pump shuts off at. The extra 1/8 gallon isn’t gonna do much for me lol.
 
Joined
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Messages
10,500
Location
Colorado
Knowing actual ECT would be helpful. If your ECT is not spiking to 200F +, then leak is more likely. If ECT is running around 200F + it may fuel boiling issue.
 

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