Mystery Drip

[dakman29]

I found this substance on the garage floor.  It's a sticky almost tarlike black goo and it was found in the location below the car shown in the pic.  There is a closeup of the stuff as well.  I could not find any areas underneath the car coated in this stuff and could not determine where it had dripped from.  Any ideas?

[Rolf-Dieter ✝︎]

Donald,

If the spot dropped from your car at position of your first photo then it looks to me like something your rear wheel might have picked up on the road and it found its way at the rear of your car or bumper then dropped off in your garage. The other possibility is some one is having fun with you and planted it under your car and then it dropped off onto your garage floor.

Dieter

[cfm65@me.com]

Dak,
Is that for Dakota?

That is also the position of your fuel tank vent and overflow. It is most unlikely that raw fuel will escape from there and desolve under body goop and drip down there.
However, I have experienced a similar goop stain below the air filter. It seems as if the cold start solinoid was leaking(not shutting off) allowing fuel to run into the air filter and escaped out the bottom taking some under body spray as evidence.
Regards
Chris
Cape Town

[dakman29]

Not Dakota. My initials. Thanks very much. I thought about fuel overflow or leak but thought I'd be able to feel a sticky area on the underside of the car and didn't. Also the overflow tube with the bell shaped end is completely dry.

[mrfatboy]

Are you missing the overflow vent as seen in the below picture? I'm am missing it and I also get the black stain sometimes.  Mostly with a full tank.  It's on my list to fix.

[dakman29]

The vent is there and the stain is on the floor just below it, but the inner surface of the vent is dry and nothing comes off on my finger when I check in there. What is the fix you speak of?

[Pawel66]

It was some effort for me to clean the expansion tank there... it maybe did not have this kind of substance inside, but it was very dirty.

Simple is to undo the vent pipe from the tank connections (just be careful not to break the fittings) and just blow through it from the upper end. You will know if there is any black stuff in it.

[mrfatboy]

My down pipe and vent were missing when I bought the car 22 years ago.   I recently bought the vent outlet from Authentic classics. My  down pipe is probably snapped off. I need to investigate .

Maybe your down pipe has a leak or disconnected somehow.  I wish I could be more help but as I said my issue is on my list to fix😜

[Paul & Dolly]

Did this occurr just after filling the tank ?

Check that you do not have a slight leak at the tank seam, the two small vent hose connections at the tank(under the cover in the "trunk"),or the filler neck.

Keep well

Paul

[dakman29]

I believe I found the problem.  Sometime back I replaced the two short pieces of fuel line connecting the vent tubes under the cover in the trunk.  I did that because of a raw fuel smell in the cabin.  Initially I used some generic rubber fuel line and that worked well.  Then I found some of the "proper" braided fabric line and installed that.  There never were any clamps on those connections but as I inspected the area over the weekend it did seem to be a bit wet and the factory insulation material was gummy and sticky in that area.  It seems that the proper fuel line may have ben slightly wider diameter than the original and fuel was leaking there.  I put some clamps on the lines and filled the tank full.  If I don't see any more drips on the floor should be problem solved.  Thanks for all your help.