oily substance
 

Hi Gentlemen,

I recently discovered at my gas shut off valve under the dash that a strange oily substance was leaking in the area. Enough of it to look like oil. Put my fingers on the valve and a sticky oily stuff was on it. can you tell me what is going on and how to fix it?????

kindly,

Vangough

Re: oily substance
 

Re: oily substance
 

You have a very,very slight weep.So slight that it doesn't drip,but slowly dries,hardens,and turns to varnish.That sticky stuff is varnish.

Re: oily substance
 

Vangogh - agree, it's not uncommon.

Your leak could be coming from one of two places:

--- Connection where the shutoff valve screws into the tank (the more common), or
--- Leaking shutoff valve with fuel leaking out of the valve body.

As to how to fix it, you need to drain the gas tank (I hook a plastic hose to the carburator end of the hard line from the sediment bowl to the carburator and run it to a gas can placed in front of the radiator), disconnect the line from the shutoff valve to the sediment bowl, and unscrew the shutoff valve from the bottom of the gas tank. Once you have the valve out clean up the threads on the valve body and in the tank (someone in the past may have put some sort of goop or thread tape on the threads), coat the threads on the valve with a fuel-proof thread sealant (do not use thread tape or thread adhesive, you need a thread sealant - I use Permatex 59214 High Temp because it's what I have, but Permatex 56521 will work also), and thread the fitting in. Don't wipe the connection, let the stuff bulge out a little bit at the base of the connection. Reconnect the inside fuel line to be sure you have it lined up properly, then let the assembly sit a couple of days so the sealant can set.

While you have the fuel valve out, this would be a good time to install a pencil filter if you don't already have one (fuel tank filter screen as an example, all the normal suppliers have them).

If you have the threads sealed up tight and still have the leak, it may be coming from the valve itself. Leaks through the valve usually are apparent when the valve won't shut off fuel flow completely. I've had poor luck with the rebuild kits offered for the valve, and have just replaced when necessary, the repro valves i've gotten seem to be decent quality. Install/reinstall per the above.

JayJay

Re: oily substance
 

Jay thanks for the advise

The oily goop is more like the subsistence of 600W

Re: oily substance
 

Leave it in place and clean it off really well and dry it well. Use some toilet paper to press against it checking for wet spots on the toilet paper. This way you will be able to tell if it is coming from the threads into the tank or the valve itself.
If and when you take the valve out of the tank be sure to have a small catch container with you as it is common for a few cups of gas to come out as the valve is removed.

Re: oily substance
 

Good points, Dave/1crosscut, thanks for chiming in.

Yup, and when you wipe the oily goop with your finger it smells awful and is difficult to get off with soap and water. That is gasoline residue.

If you want to confirm, put about a teaspoon full of gasoline in a glass container (like a custard cup) and let it evaporate for a day or so. You'll get the same stuff. (Clean the custard cup out thoroughly and run it through the dishwasher before the Significant Other finds out you requisitioned the container, though.)

JayJay

Re: oily substance
 

To repair the fuel valve, consider some EZ-turn lubricant. It will not dissolve in gasoline. See https://www.aircraftspruce.com/catal...ezturnlube.php.

Re: oily substance
 

Also, after draining the tank, jack up the side of the car so any residual gas in the tank will move to the opposite side. Still have the catch container "just in case".