Small hole in fuel filler tube (1 Viewer)

[bb67tlc]

You might have seen my post in "what have you done to your..." about parking on a slope with a full tank. Just noticed this small hole by the gas cap, which seems purposeful and original. This is actually where the fuel came out, not through the cap itself. What's the purpose, to avoid a vacuum? The gas cap has a new gasket but it is not a perfect seal. Can I fill this in?

 

[Living in the Past]

I just figured it was a vent. But possibly could be to anchor the chain for the gas cap. My 68 didn't have chain. Believe my 70 has a tab on the inside of the lip for the chain. But know my 68 has the weep hole. When I had two tanks and needed them I would run the aux out first since it didn't work the fuel gauge. With a full main tank has would run out in steep grades. Yesterday could have looked at both but no for a week or two.

 

[65swb45]

I have never seen a factory weep hole. You need a new filler neck.

 

[Living in the Past]

I have never seen a factory weep hole. You need a new filler neck.

Think this is to guarantee the tank does not go into a vacuum if a non vented gas cap is used.

 

[middlecalf]

LITP you can add mine on my early ‘63.

 

[65swb45]

back at you. Even if it is a widespread coincidence (based on a ‘tech’ tip in an old car magazine) It is simply not logical for any car manufacture to purposefully build a part in such a way that it is guaranteed to produce fumes and stain the paint on a new vehicle.

 

[Living in the Past]

back at you. Even if it is a widespread coincidence based on a ‘tech’ tip in an old car magazine) It is simply not logical for any car manufacture to purposefully build a part in such a way that it is guaranteed to produce fumes and stain the paint on a new vehicle.

These are all the same size in the same location to be a coincidence. The red fill neck is off a cruiser made in the second half of 1962. One of the beige ones is probably off a 69 I parted many years ago. If this would have been before noon yesterday could have checked my 10/69. Once the return line from the carburetor started I'm sure it when away. Fumes would be awful if the tank was vented. I personally can say I've really noticed fumes from early cruisers parked in a garage.

 

[Living in the Past]

back at you. Even if it is a widespread coincidence (based on a ‘tech’ tip in an old car magazine) It is simply not logical for any car manufacture to purposefully build a part in such a way that it is guaranteed to produce fumes and stain the paint on a new vehicle.

Not sure how logical Toyota was originally. How about the defrost vents that started in 1962. Only had a hard top and pickup from this era. When Destin did his restore thread in the 25 section years ago it verify Toyota used the same vents that had to be removed to fold the windshield down. Or the early driver's seat that four nuts had to be loosened to adjust.

 

[rainingagain]

This thread got me curious so I went out and looked at mine. Factory 1967 filler neck, WITH a weep hole. Very interesting.

 

[73FJ40]

How does the chain for the OEM cap attach to the filler neck?

 

[bb67tlc]

All very interesting- I would've put the hole at the top. Since my cool locking cap (which I believe is original) is not airtight, I'm filling the hole... and then trying not to fill too high.... and then choosing wisely when parking on a slope.

 

[red66toy]

I have had serious gas leaks on a hot day from this “weep” hole. Ruined my fresh paint job. My cap doesn’t have a chain on it and maybe that was the issue. This had to have been the anchor point for the chain screw. No way that is a factory vent hole. Makes no sense.

 

[Living in the Past]

How does the chain for the OEM cap attach to the filler neck?

View attachment 2473403

The is a tab on the inside lip with a hole to secure the end of the chain. Could snap a picture of you would like.

All very interesting- I would've put the hole at the top. Since my cool locking cap (which I believe is original) is not airtight, I'm filling the hole... and then trying not to fill too high.... and then choosing wisely when parking on a slope.

Owned my 68 since 1974. Gas running out the small hole was rarely a problem. Original paint does not have a clear coat and have not had an issue with the paint. My FJ62 with clear coat has issues from the first owner spilling gas when he filled it. Have a few 40 with original paint and surprised what will rub out.

I have had serious gas leaks on a hot day from this “weep” hole. Ruined my fresh paint job. My cap doesn’t have a chain on it. This had to have been the anchor point for the chain screw. No way that is a factory vent hole. Makes no sense.

I can show you the hole for the chain. Think my 68 had a cotter pin in the weep attached to a chain. But that was forty six years ago. showing a picture isn't a problem.

 

[Mark Jennings]

Yep got a 68....yep got a weep hole....same place....same hole.....it’s actually the vent.

Most of you are probably to young to remember the sweet smell of Gasoline on a hot summer day in a black top parking lot....back before they had them there new fangled charcoal canisters....

Yep, back when the Toyota-sorous-rex roamed the woodlands...looking for a tasty jeep..,.trapped in a mud pit....we vented directly to the environment....

Shame on us (lol)

 

[red66toy]

Do most older cars of that generation have a straight hole like this for venting out the side of the vehicle? I thought a vented gas cap would allow air in to prevent vacuum only. Also, if this hole was for venting.. in case a non-vented cap was used, its presence makes the use of a vented gas cap pointless and has no regulation of venting itself. I think the fact that its so easy for gas to expand and pour out on a hot day with a full tank, or for gas to pour out if you are on a angle seems like a terrible design and one Toyota would have fixed. Its not some annoying thing like defrost vents that have to be removed to fold down the windshield (yes that is a super dumb design since its a pain to remove those vents).
This is a interesting topic and curious to see if there is a solution/conclusion. I have had gas come out of this weep hole on several occasions during hot California summers. Enough times to make me paranoid about filling the tank. I am curious to know if many other early 40 owners have had this issue or if its rare? Maybe just covering the hole and running a vented cap is the final fix and forget?

 

[Living in the Past]

Do most older cars of that generation have a straight hole like this for venting out the side of the vehicle? I thought a vented gas cap would allow air in to prevent vacuum only. Also, if this hole was for venting.. in case a non-vented cap was used, its presence makes the use of a vented gas cap pointless and has no regulation of venting itself. I think the fact that its so easy for gas to expand and pour out on a hot day with a full tank, or for gas to pour out if you are on a angle seems like a terrible design and one Toyota would have fixed. Its not some annoying thing like defrost vents that have to be removed to fold down the windshield (yes that is a super dumb design since its a pain to remove those vents).
This is a interesting topic and curious to see if there is a solution/conclusion. I have had gas come out of this weep hole on several occasions during hot California summers. Enough times to make me paranoid about filling the tank. I am curious to know if many other early 40 owners have had this issue or if its rare? Maybe just covering the hole and running a vented cap is the final fix and forget?

I've always wondered how vented are the gas caps we call vented. Look at listing on site that actually give you dates for changes and the part number to discription doesn't say vented. With the hole really no need for a vented cap. Always wonder if it wasn't a safety concern. Places like the Middle East you don't need a sealed gas baking out in the desert. Charcoal filters would allow pressure to be released. Prior to those venting straight to the atmosphere is how it was done. When I was young lived in the Midwest. Used motor oil was used on dirt roads to keep the dust down. Kids rode in the back with no seat belts. Front seats had seat belt first. No one used car seats secured with a seat belt for a baby. Today see a kid standing in the back seat and people think what an awful parent. Can't use today's standards for fifty years ago.

 

[Mark Jennings]

Do most older cars of that generation have a straight hole like this for venting out the side of the vehicle? I thought a vented gas cap would allow air in to prevent vacuum only. Also, if this hole was for venting.. in case a non-vented cap was used, its presence makes the use of a vented gas cap pointless and has no regulation of venting itself. I think the fact that its so easy for gas to expand and pour out on a hot day with a full tank, or for gas to pour out if you are on a angle seems like a terrible design and one Toyota would have fixed. Its not some annoying thing like defrost vents that have to be removed to fold down the windshield (yes that is a super dumb design since its a pain to remove those vents).
This is a interesting topic and curious to see if there is a solution/conclusion. I have had gas come out of this weep hole on several occasions during hot California summers. Enough times to make me paranoid about filling the tank. I am curious to know if many other early 40 owners have had this issue or if its rare? Maybe just covering the hole and running a vented cap is the final fix and forget?

One way check valves in gas tanks were not introduced until about 1973, e.g. the caps would allow air in to prevent drawing a vacuum but closed on pressure.

In the 70’s it was not uncommon to hear your gas tank tank ‘thump’ as the day warmed up and the vapors in the tank expanded.

 

[Mark Jennings]

Do most older cars of that generation have a straight hole like this for venting out the side of the vehicle? I thought a vented gas cap would allow air in to prevent vacuum only. Also, if this hole was for venting.. in case a non-vented cap was used, its presence makes the use of a vented gas cap pointless and has no regulation of venting itself. I think the fact that its so easy for gas to expand and pour out on a hot day with a full tank, or for gas to pour out if you are on a angle seems like a terrible design and one Toyota would have fixed. Its not some annoying thing like defrost vents that have to be removed to fold down the windshield (yes that is a super dumb design since its a pain to remove those vents).
This is a interesting topic and curious to see if there is a solution/conclusion. I have had gas come out of this weep hole on several occasions during hot California summers. Enough times to make me paranoid about filling the tank. I am curious to know if many other early 40 owners have had this issue or if its rare? Maybe just covering the hole and running a vented cap is the final fix and forget?

It wasn’t a terrible design......it was just the standard.....need a vent.....drill a hole at the high point.....you see, in some respects, emission regulations are (were) a good thing. With a controlled vent through a charcoal canister, no uncontrolled hydrocarbons, no dripping filler necks, your nice new paint wasn’t ruined, etc... (lol).

 

[red66toy]

So if one wanted to cover this ill designed "vent" (now that we know this is not a great design), what is a vented cap that will fit on our old rigs?

 

[Living in the Past]

So if one wanted to cover this ill designed "vent" (now that we know this is not a great design), what is a vented cap that will fit on our old rigs?

People always assume the original gas caps were vented. I'm not.100% convinced. I obviously have a spare fill neck or two. Would be easy to solder shut the small hole and bottom opening. Then a simple matter of putting a air system to the small vent tube that prevents gas from pushing gas up when filling then see if it bubbles at the cap when submersed under water. Or just plug the hole and see if the tank goes into a vacuum with the engine running and gas cap on.