Oldracerjones

Just bought a "restored" 70 442. Smelled gas the next morning in the garage so checked the next day and found a small puddle of very dark liquid that smelled like gas under the tank. The color worries me more than the leak, appears the restore did not include cleaning and/or replacing the tank. Looks like I will have to do so. I see some stainless tanks on line and they appear to be pretty good with several of our members writing posts about them.
Anything I need to know or advice you may have before I take the plunge?

Allan R

Yes, get the car up on a ramp or hoist and check to see if the leak is coming from the tank, the fuel line, or the rubber hoses for vent and main fuel line. You may be lucky and find that it's just rubber hoses that need to be replaced.

Look under the car and see if the gas was dripping from the tank or somewhere else.

oldcutlass

X2 on what Allan suggested.

MDchanic

X3. Drop the tank and look. A drip from a hose can travel along the tubing to the top of the tank, then along the top of the tank and drip off of one corner onto the ground.

- Eric

stan 65 cutlass

the dark color may be undercoating washing off

Miles71

The tank on my 71 CS was in good shape.

However, all of the 6+ venting and fuel lines attached to the tank had aged and some even cracked in half.
I then replaced all of the fuel and venting hoses with new Ethanol rated fuel lines.
I will still see a small puddle under the tank from the condensation vent canister.
My puddle is usually about 1 teaspoon or less with a mixture of water and gas.
The color is a shade of yellow.
The liquid will sit on the cement floor for a few days until it evaporates.
Since the mixture is not pure gas or water, it seems to take much longer to evaporate.

Suggestions:
If your lines are not Ethanol rated, then replace all of the rubber hoses associated with your fuel system, front and rear.

Oldracerjones

Put the car on my lift and found a couple things. First, the connection from the filler tube to the tank was pretty wet. There was also wet areas under both straps. The strap on the left side of the tank was the area that was dripping.

I think I will replace the tank but am wondering how, short of pulling the tank, can I determine the type or number of vents on the tank so I order the correct one?

hookem horns

Spectre makes a very good tank for less than stainless. Several options to buy online and take shipping into account when choosing. New sender and all rubber hoses make sense while doing the job, maybe straps and bolts depending on condition. A member here (Patton - can't recall his user name) sells a nice affordable tank pad.

Oldracerjones

Looks like the tank may be leaking at the neck and the seam at the top the. Running down under the straps. I've decided to change the tank and looked at the plumbing for it today.

It has two lines out of the top center that go to the front of the car then enter a small canister, then one line goes to the fuel pump on the engine and the other goes back into the canister.

There are two more lines that come out of the right top that go to a single fitting close to the tank. The fitting merges both lines into one outlet line that has nothing on it. It is just open to the air. That may be where my gas smell is coming form.

Shouldn't those lines be going into a charcoal canister or something?

My question is would this tank be considered a 1,2, or 3 vent tank?

455man

You might check out wild about cars. They have factory publications that show these lines. Might also do a search. I'm thinking this info is on here somewhere. Those two lines should go somewhere not into the air.

66400

Patton is 70Post

Henry

hookem horns

Definitely check out that site and/or get a paper copy of the service manual. 1970 was the transition year on the charcoal evap system, maybe only the CA cars got it. Two vent lines with the "surge" cap was normal prior to that and just vented to the atmosphere so some fumes do escape but should not cause a big odor. On the sender, two lines were used for big block cars (supply and return at the fuel pump) but small block cars only have a single supply line.

Oldracerjones

Went through the manuls on the site today. It clearly supports what I need to know. Thanks..

Oldracerjones

It clearly looks like the vent lines are normal. I think the majority of the fumes are coming from the leak at the filler neck to tank interface. There is no charcoal canister on the fenders or anywhere in the engine compartment.

Oldracerjones

Replaced the gas tank this weekend. No leaks, much better piece of mind. Thanks to all who offered advice.

Allan R

Glad you got it fixed. Nothing worse than having to worry about a fuel problem. Just got back from sunny Cancun last week and didn't see your post till just tonight. Did you go with Spectra Premium for your tank? I used them for my 72 and am very happy with it.

Oldracerjones

Yes, used the spectra. Easy install, quality tank.