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| | | | Joined: Nov 2005 Posts: 206 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 206 | Any way to prevent gasoline from boiling out of gas cap on a task force truck when left in sun and height temps? I thought the filler neck had a overflow tube to prevent such occurrence ? Would a new gas cap prevent it. Took the two stage paint right off my truck. Tank was not overfilled at time. About 9/10 th full. | | | | | Joined: Aug 2005 Posts: 6,378 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,378 | Any vented gas cap will allow gas to escape. The only way I know to prevent expanding gas overflow is to not fill the tank as full. Were you maybe parked on a slope with the neck down hill?
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
| | | | | Joined: Apr 2005 Posts: 7,441 Bolter | | Bolter Joined: Apr 2005 Posts: 7,441 | Fill to 8/10 unless your going to be driving a bit. I never fill mine all the way, until the nozzle clicks off, in the heat of the summer and then park it. Keep it well below the fill pipe. ðŸ›
Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line"! Hug a cop!
USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
| | | | | Joined: Mar 2004 Posts: 6,236 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,236 | If your talking about a TF truck, the small line on the filler neck is an air vent to allow air to escape the tank while filling it up, it's not an overflow drain. You need to allow for expansion. Mike B  | | | | | Joined: Oct 2016 Posts: 496 Shop Shark | | Shop Shark Joined: Oct 2016 Posts: 496 | Yep, had to syphon gas out twice because it was pouring out the gas cap. I just stick the nozzle as far as it will go and stop on the first click.
1950 SUBURBAN / SCHOOL BUS A.K.A "THE SCHOOL RUST"
| | | | | Joined: Jul 2007 Posts: 66 'Bolter | | 'Bolter Joined: Jul 2007 Posts: 66 | Ya...I have the same problem If I fill to about 3/4 and then sit in the sun, the gas will just pour out the cap and all over the running board. I thought maybe a new gas cap but I don't know for sure... | | | | | Joined: Mar 2017 Posts: 326 'Bolter | | 'Bolter Joined: Mar 2017 Posts: 326 | I learned to fill up on my way into town first thing so the level would drop as I was doing my errands. I am still working on the problem of fuel leaking out the top of the sending unit when the tank is full. I think it is coming from the mounting screws, but I have not found a solution yet.
1956 Chevy 3200, 235 w/3 speed
| | | | | Joined: Sep 2017 Posts: 135 Shop Shark | | Shop Shark Joined: Sep 2017 Posts: 135 | That gas has to go somewhere, better to have it come out the cap than out in the truck. Drive it after filling it, or add an expansion tank. | | | | | Joined: Aug 2005 Posts: 6,378 Ex Hall Monitor | | Ex Hall Monitor Joined: Aug 2005 Posts: 6,378 | I think it is coming from the mounting screws, but I have not found a solution yet. If that's where it's coming from try using pipe dope on the screw threads. Use a dope that's chemical resistant. Pipe dope won't lock the fastener like thread locker will but will provide some protection from loosening and seal the threads.
Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.
| | | | | Joined: Jan 2010 Posts: 4,263 Shop Shark | | Shop Shark Joined: Jan 2010 Posts: 4,263 | Im under the suspicion that the new replacement vented gas caps do not vent properly.
Both bringing air in and venting air out.
I think they are using springs that are to strong
If you have an old or nos cap hang on to it | | | | | Joined: Nov 2005 Posts: 206 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 206 | Thank y'all for the solid advice. Once burned twice learned | | | | | Joined: Dec 2013 Posts: 795 Former BMW Rider | | Former BMW Rider Joined: Dec 2013 Posts: 795 | Im under the suspicion that the new replacement vented gas caps do not vent properly.
Both bringing air in and venting air out.
I think they are using springs that are to strong
If you have an old or nos cap hang on to it I would agree. It took me a while to come to that conclusion. However, since I made sure my reproduction cap is 'vented', I've not had a problem.......... | | | | | Joined: Mar 2010 Posts: 10,310 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,310 | I "vented" my reproduction cap with a 1/8" drill bit through the plastic center on the inside of the cap. No more belch of fumes and no more giant sucking sound.
The new rubber (probably PVC) gaskets are real tight on the screws which prevents leaking.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: Jan 1970 Posts: 365 Shop Shark | | Shop Shark Joined: Jan 1970 Posts: 365 | This topic describes how my 51 caught fire. I had the tank more full than normal and was parked on a slope, with the cap downhill. I was welding nearby and heard a noise, I removed my welding helmet to see the side of my pickup on fire. It took the FD to get the fire knocked down. See my post from several years ago titled "A bad day for my 51" | | | | | Joined: Jan 2017 Posts: 23 'Bolter | | 'Bolter Joined: Jan 2017 Posts: 23 | I "vented" my reproduction cap with a 1/8" drill bit through the plastic center on the inside of the cap. No more belch of fumes and no more giant sucking sound.
The new rubber (probably PVC) gaskets are real tight on the screws which prevents leaking. I did the same. The new cap was not venting well enough so fuel was coming out where the sending unit mounts. No more raw fuel smell in the cab!
1954 3600
| | | | | Joined: May 2001 Posts: 1,907 'Bolter | | 'Bolter Joined: May 2001 Posts: 1,907 | My '48 has the under bed tank. I put my ear to the filler neck and stop the flow at the first sound of gurgle. That was the way everyone did it before the automatic shut-off was invented.
1948 3/4-Ton 5-Window Flatbed Chevrolet 34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
| | | | | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 | I do the same thing Wally does.
Do not nurse it to full, when "filling up".
As another precaution, I usually "fill-up" when I have the time for a 10-15 mile round-trip road-trip.
I have had no "overfill/expansion" leakage in over 20 years. | | | | | Joined: Apr 2016 Posts: 1,054 'Bolter | | 'Bolter Joined: Apr 2016 Posts: 1,054 | When I was young and my 53 was my only / work truck it wasn't a problem because I seldom had enough money to fill it up.
Old enough to know better, too young to resist.
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