Gas tank leaks randomly... cracked? rusted? gas gnomes?

[Rexx66]

Doesn't seem to be any rhyme or reason why it does, but I noticed the gas tank leaking a few nights ago from the bottom passenger side of the tank. Drove it to work the day after noticing the leak, and it stopped, and didn't leak a drop for about 3 days.... until today its doing it again.

I have noticed the temp here has been cooler in the mornings, and then warmer/hot as hell later in the day. (Southern Indiana)

Could it possibly be a cracked/rusted tank causing an intermittent leak? I've found an el cheapo tank with straps on eBay, and I know it isn't high quality, but this thing will rarely be driven in the rain and never taken off road.

I plan on dropping the skid plate tonight to see the bottom of tank, which I'm sure is where its coming from... all the hoses connected to the tank show no signs of leaking or dry-rot.. and are connected just fine and tight.

Any ideas?

 

[Torxhead]

A crack on the tank is possible, gas coming out of a cracked fuel line that doesn't appear cracked, or coming thru the gas gauge send unit.

 

[Rexx66]

A crack on the tank is possible, gas coming out of a cracked fuel line that doesn't appear cracked, or coming thru the gas gauge send unit.

I will double check all hoses tonight when I get under it, it has a body lift so its all really easy to get to. I just don't see how its leaking currently it would be the hoses, the locations are completely different. I will pop the skid plate off and hopefully see where it's coming from. If I see it, then I will have to order a new tank.

 

[Rexx66]

I'm going with the gas gnomes theory... Its been about a week or so and has been back to the gas station where I topped it off and it hasn't leaked a drop since...

 

[Torxhead]

Thanks for the update, I am sure you will be having future issues. Having a good fire extinguisher handy is always a good plan also.

 

[thiswontbetooexpensive]

~~Having a good fire extinguisher handy is always a good plan also.

And/or and escape plan and good insurance!

 

[Saddle Tramp]

Question: How full was the tank? Did you just fill it then find the leak later in the day (or the next day) after it warms up? Gas comes out of the ground at underground temps (cold) and will expand if it is a hot day which will force it out of the hose connections. From the info in this picture there are hoses on both the driver’s and passenger side of the tank unless your jeep is a California model. (1977 through 1979 should all be the same)

 

[Rexx66]

Ended up having to drop the gas tank tonight as the leak had started once again but was far worse than the occasional drip like before. After some cussing kicking and sweat, the tanked finally dropped.

Once I got the tank out I removed it from the skid plate and didn't notice any leaks on the sides or top, then I looked on the bottom and found this nice surprise....



So no matter what amount of gas was in it... It was bound to leak. Not sure if it was rust or if it had someone been punctured through the skid plate.

I plan on replacing the tank completely and not even bothering with saving the fuel or the old tank. Appears it has maybe been JB WELDED or something, an since my daughter rides with me I can't just ghetto rig fix it.

Assuming this is the 15 gallon tank, where is a cheap place to get a tank? eBay has some for $85 but didn't know the quality, and also should I get a new one and paint it with some type of anti rust paint before installing?

 

[73CJ]

Pretty common for the tanks to rust from the outside of the bottom in the rust belts. For a temporary fix rub it with a bar of soap. Doesn't last long but works for a day or two.

On my 73, the tank rusted bad after 8 years.

For some reason they put an open cell pad under it and it stayed wet forever rusting through.

I went plastic and closed cell pad.

 

[PaRenegade]

I recommend the extra dollars for a poly tank if your going to have the Jeep for a few more years. If not and you put in another steel tank, paint it well with some quality paint and etching primer under it. Paint the skid plate also. 73CJ is right, they commonly rust on the bottom from the outside in, usually due to trapped dirt that acts as a sponge and stays damp. Was the plastic spacer still there between the tank and skid?

 

[Rexx66]

I recommend the extra dollars for a poly tank if your going to have the Jeep for a few more years. If not and you put in another steel tank, paint it well with some quality paint and etching primer under it. Paint the skid plate also. 73CJ is right, they commonly rust on the bottom from the outside in, usually due to trapped dirt that acts as a sponge and stays damp. Was the plastic spacer still there between the tank and skid?

There is 2 different pieces of pretty haggard looking rubber/plastic pieces. I was talking to a buddy about maybe painting the new tank with something to help protect it from rusting again. At least slow the process down. I have some etching primer, and enough paint laying around something is bound to work OK on it.

Going to pick it up tonight and hopefully get her installed. There isn't a pump IN the tank is there? I plan on installing the my new fuel sender also.

 

[Petescj]

There isn't a pump IN the tank is there? I plan on installing the my new fuel sender also.

Nope , just the good old mechanical pump bolted up to the block.

 

[JR74CJ5]

You can get the tank from Summit Racing, one of our sponsors like Morris 4x4 (10% off - click the sponsors tab near the top of the site for discount code), or many other places. The e-bay on for 85.00 seems like a good deal though. Not sure which you're looking at to vouch for quality, but IO personally ordered the Summit one not too long ago.

Yours is a bit newer than mine, so probably different tank though.


~ Jr

 

[Rexx66]

You can get the tank from Summit Racing, one of our sponsors like Morris 4x4 (10% off - click the sponsors tab near the top of the site for discount code), or many other places. The e-bay on for 85.00 seems like a good deal though. Not sure which you're looking at to vouch for quality, but IO personally ordered the Summit one not too long ago.

Yours is a bit newer than mine, so probably different tank though.


~ Jr

I ordered mine through the Advance Auto Parts site (I have one about 1 mile from the house), checked out some promo codes online and found one for $130, after the promo code it made it $80 plus tax, ship to store, now I'm on my way to pick it up. I believe the brand is Spectra

 

[Rexx66]

Alright, got the new tank in with the new fuel sender.. Used some etching primer and painted it black. Upon me inspecting it, apparently something had pierced through the skid plate, the plastic piece, and through the tank. It was done by the PO, and was "repaired" using JB Weld...

The tank was rusty, but not the culprit I'm pretty sure.

Now the current "issue", is that even with a new fuel send in, my gauge is reading a full tank still. I'm leaning towards the gauge is messed up or just not "the right type". It's an aftermarket one the PO purchased from O'Reilly auto. I've checked all wires and resistance, and it's the only thing left that it could be.

Any ideas on a decent fuel gauge?

ALSO...

Got the exhaust swapped out and running a Thrush GlassPack and the CJ5 sounds mean as hell now..