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Yesterday I drove my ’74 Coupe, filled up with gas and then parked it in my garage around 2pm with no issues … it was really running great and everything seemed fine.
Around 6pm my wife and I went out in her car, which was parked right beside my Vette and still everything seemed fine, no gas smells in garage. We got back around 11pm and parked in garage beside my Vette and again everything seemed fine.
This morning I got up to the faint smell of gas. Our bedroom is at the opposite end of the house from the garage. By the time I got to the garage the smell was getting scary … really strong.
I took a flashlight with me, not wanting to flip any light switches and went into the garage and there was a puddle of gas that extended from my Vette to about 4 or 5 ft away on the drivers side. I manually opened the garage door and pushed my Vette outside and once outside looked underneath and saw no leaks. I spend several hours venting all the fumes out of the house, basement and cleaned up the mess in the garage.
Not counting evaporation, it looked like maybe a half gallon or less of gas was on the floor.
I started my Vette and checked for leaks … still seeing nothing I pulled it into the garage and got under it to check for leaks. No leaks on top around carb, manifold or fuel lines. Underneath the fuel pump fittings are all dry and the only sign I can find is on the splash shield that is under the charcoal canister on the drivers side. When I got my fingers up on it’s top side it’s wet and smells like gas. I haven’t removed the splash shield yet as I’ll have to take the rocker molding off first so I haven’t actually found the source of the leak but has anyone else had a problem like this and what could cause it. Thanks
Yesterday I drove my ’74 Coupe, filled up with gas and then parked it in my garage around 2pm with no issues … it was really running great and everything seemed fine.
Around 6pm my wife and I went out in her car, which was parked right beside my Vette and still everything seemed fine, no gas smells in garage. We got back around 11pm and parked in garage beside my Vette and again everything seemed fine.
This morning I got up to the faint smell of gas. Our bedroom is at the opposite end of the house from the garage. By the time I got to the garage the smell was getting scary … really strong.
I took a flashlight with me, not wanting to flip any light switches and went into the garage and there was a puddle of gas that extended from my Vette to about 4 or 5 ft away on the drivers side. I manually opened the garage door and pushed my Vette outside and once outside looked underneath and saw no leaks. I spend several hours venting all the fumes out of the house, basement and cleaned up the mess in the garage.
Not counting evaporation, it looked like maybe a half gallon or less of gas was on the floor.
I started my Vette and checked for leaks … still seeing nothing I pulled it into the garage and got under it to check for leaks. No leaks on top around carb, manifold or fuel lines. Underneath the fuel pump fittings are all dry and the only sign I can find is on the splash shield that is under the charcoal canister on the drivers side. When I got my fingers up on it’s top side it’s wet and smells like gas. I haven’t removed the splash shield yet as I’ll have to take the rocker molding off first so I haven’t actually found the source of the leak but has anyone else had a problem like this and what could cause it. Thanks
the gasoline in the under ground tank is at 55 degrees and if you fill the tank clear full till the top of the neck as the gasoline heats up to ambient temp it will expand and be pushed out the overflow.
Last edited by PAmotorman; 02-25-2017 at 01:17 PM.
Thanks PAmotorman. Usually I fill it up until the fuel reaches the bottom of the filler neck but yesterday I did fill up a little more ... it came up maybe an inch above the bottom of the neck. The puddle looked like it originated from the drivers side and when I got the splash shield off, the bottom of the charcoal filter is wet with gas. That and the inside of the splash shield is the only gas residue I can find. Nothing wet at the tank.
What you said sounds reasonable! If that's what happened is the charcoal canister considered to be the over fllow point? There is a tube coming out of the bottom of that canister.
Hi J,
Something else to check.
On the 74 there is a fuel separator checkvalve located on the top driver's side of the tank. It's not easy to get to. It's function is to keep what happened to your car from doing that. It may be bad and need replaced. Once you remove it, (if you decide to) you can check it by shaking it to hear the check ball rattle. Then blow in one of the ports air should pass through. Turn it upside down and blow air should not pass through. That means it is funtioning. Also take a close look at the bottom seam of it, they tend to leak there. You can remove the bottom of your vapor canister and dry out the filter too!
Here's a photo of the fuel separator valve and the bottom of the canister. All the vendors sell them if yours needs replaced. I would drive the car some first as suggested above before taking off the valve. It is not an easy job. If you have the problem again, then you should check the valve.
Hope this helps!
Tooch
The refineries are producing winter fuel blends this time of year and they are more prone to the expansion you describe. If it is also blended for altitude it will be even more prone to expand. Your charcoal evaporation canister is probably saturated as to be expected. It will dry out by driving it.
Don't worry yourself too much now that it's over and done. You handled it impressively and intelligently (i.e. taking no chances by manually opening the garage door.). You would be surprised how often this happens, usually to the people you see/hear at the gas pump where you hear repeated filler hose automatic shut off clicks. You should always stop filling a gas tank once you hear it clicks off. Maybe after the second click.
Spray water and then a degreaser on your garage floor using a broom to rub it in and let it sit for a few minutes before spraying it out with a garden hose. You'll be right back in business with your mechanical family member, never to happen again
Ha ha ... no problem with that fix. Thanks theandies
Tooch1 ... yes I'm familiar with that valve and saw it when I replaced the tank a few years ago. It seemed fine then but I know exactly where it's at. Didn't see any leaks from the back of the car on the garage floor but I'll see if I can get to it.
Thanks for the tip on the canister ... I'll see if I can get the bottom off while I''ve got the splash shield out of the way.
I've posted on this subject once or twice before. In my case, I filled up to the neck and drove a short distance home where the car sat in the sun. The gas pushed past my needle valve and hydrolocked my motor. I thought the starter was bad. Happily I figured it out before I got the engine running as my oil was completely diluted.
Oh great ... something new to worry about. Thanks ignatz
Glad to be of service. I guess I didn't mention the time my gas tank rotted out along the rail and gas would slowly drip onto my hot mufflers. One errant cigarette butt in the parking lot, and BOOM!
Thanks PAmotorman. Usually I fill it up until the fuel reaches the bottom of the filler neck but yesterday I did fill up a little more ... it came up maybe an inch above the bottom of the neck. The puddle looked like it originated from the drivers side and when I got the splash shield off, the bottom of the charcoal filter is wet with gas. That and the inside of the splash shield is the only gas residue I can find. Nothing wet at the tank.
What you said sounds reasonable! If that's what happened is the charcoal canister considered to be the over fllow point? There is a tube coming out of the bottom of that canister.
take it off and see how heavy it is. if it is loaded with fuel you may have to replace it as the charcoal is saturated with gasoline
Here is the check valve installed. It's located on the back left corner of the tank (this is on my '71). The big hose comes from the tank and the small hose goes from the valve to the frame rail hard line up the the vapor canister. This shot is looking from back to front
take it off and see how heavy it is. if it is loaded with fuel you may have to replace it as the charcoal is saturated with gasoline
Canister is heavy and the air filter on the bottom was soaked. Also when I took off the line that comes from the tank, gas spilled out so I'm guessing that line is full of gas which I think also means that the valve at the top drivers side of tank must be defective. I think it's supposed to keep gas from getting into that line.
For now I think I'll plug the line from the tank and also plug the line going to the intake manifold. The gas cap is a vented cap but the orifice has been sealed off so I'll unseal that so it will be a functioning vented cap until I can get to replacing the valve & canister. I think there's a valve in the top of the canister that may also be bad and may check that if I can find a procedure. Thanks again.
Here is the check valve installed. It's located on the back left corner of the tank (this is on my '71). The big hose comes from the tank and the small hose goes from the valve to the frame rail hard line up the the vapor canister. This shot is looking from back to front
Thanks ... I think that must also be bad. Appreciate the photo, all the photos everyone has posted.
Got to run for now ... the wife is forcing me to take her out for dinner. I'll update this post if I get everything solver/resolved but other than some of this being a real pain to get to ... I'll try to take advantage of the rest of winter to get this taken care of.
Hi,
Here's the mount for the vapor separator that's been shown and it's hose connections.
It's typically the muffler that makes access to it a bit difficult.
Regards,
Alan
Alan is right. If you can remove or swing the muffler out of the way it makes it easier. What also might help get the muffler out of the way is to remove the spare tire carrier.
I just finished removing my tank to replace the valve and all the rubber hoses. Getting the tank out is easy, remove the cross member bolts and it falls in your lap. I spent 45 minutes trying to re-install it with no results. Had my wife help me, took 7 minutes. Two hands cannot hold the tank, hold the cross member and install the nuts and bolts.
I have now replaced all rubber fuel lines, front and rear, rebuilt the vapor cannnister, and have zero fuel odor in my garage after I drive it. I never, ever, fill my tank to the top.
Hi J,
Something else to check.
On the 74 there is a fuel separator checkvalve located on the top driver's side of the tank. It's not easy to get to. It's function is to keep what happened to your car from doing that. It may be bad and need replaced. Once you remove it, (if you decide to) you can check it by shaking it to hear the check ball rattle. Then blow in one of the ports air should pass through. Turn it upside down and blow air should not pass through. That means it is funtioning. Also take a close look at the bottom seam of it, they tend to leak there. You can remove the bottom of your vapor canister and dry out the filter too!
Here's a photo of the fuel separator valve and the bottom of the canister. All the vendors sell them if yours needs replaced. I would drive the car some first as suggested above before taking off the valve. It is not an easy job. If you have the problem again, then you should check the valve.
Hope this helps!
Tooch
Thanks for that solution. I hope it works since I also have that issue w/my 74
02-25-2017, 01:09 PM
Woke up this morning to the smell of gas!
Thanks ignatz
I'll update this post if I get everything solver/resolved but other than some of this being a real pain to get to ... I'll try to take advantage of the rest of winter to get this taken care of.
