Gas tank spewing gas! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**bigdon-70blazer** · 10-30-2009, 10:37 PM

I got the Blazer fired up tonite! Ran for a while and now we have to do the details but it ran for a while and we shut it off. Not traveling under own but soon. Did do something curious though. Poured gas into the tank and after a short bit, tank rumbled and spewed gas back out the filler. All over me but that is not important. I used another 1969-70 era gas tank after I determined original had leak. Cleaned the one I put in well and replumbed the entire works with new rubber gas lines where needed. Used the old sender unit as it was in pristine condition, only 56K miles on rig. The gas in being pumped from the tank to carb so that works fine. Haven't got enough gas in it to determine if the gauge works yet. Any ideas? I am going to trace down the vent lines tomorrow but thought I would ask. Also, need throttle solution for the new holley 600 carb. I removed the old quadrajet so you know what my linkages looked like originally, they don't work with this set up. Thanks. Starrted after almost 4 years!

tcb-1 · 10-30-2009, 11:12 PM

sounds like a simple vessel over pressurization. my guess is a clogged/kinked vent tube OR the cap is not allowing proper venting. my old motorcycles had to be able to vent through the cap or bad things would happen.

interesting nonetheless. and CONGRATS on the beast roaring to life! give her a kiss from us!

**lks dcvn** · 10-31-2009, 08:01 AM

Is it coming out of the filler tube on the side of the truck - if so - that is some pressure driving the gas out.

Did you replace all the lines to/from the tank as well.

Vent - 3/8" or 1/2" (can't remember which)
Gas Intake line - 1 3/8" (Marine store or Napa might be able to get it)
Charcoal Filter line (Might only be on 72 models) - 3/8 or 1/2" (can't remember which)

It can be a pain to drop the tank to replace these so hopefully it is still somewhat empty from gas to do this. When I drop the tank I replace all the lines on the tank just to be sure that none of the other lines are problematic/clogged...

If after that it is still doing it - try to run it without any other lines on the tank except the one pulling the gas to the carb.

**bigdon-70blazer** · 10-31-2009, 08:09 AM

Quote:

Originally Posted by lks dcvn

Is it coming out of the filler tube on the side of the truck - if so - that is some pressure driving the gas out.

Did you replace all the lines to/from the tank as well.

Vent - 3/8" or 1/2" (can't remember which)
Gas Intake line - 1 3/8" (Marine store or Napa might be able to get it)
Charcoal Filter line (Might only be on 72 models) - 3/8 or 1/2" (can't remember which)

It can be a pain to drop the tank to replace these so hopefully it is still somewhat empty from gas to do this. When I drop the tank I replace all the lines on the tank just to be sure that none of the other lines are problematic/clogged...

If after that it is still doing it - try to run it without any other lines on the tank except the one pulling the gas to the carb.

Yes I changed all of the rubber hoses while the tank was down.

**bigdon-70blazer** · 10-31-2009, 08:12 AM

Seem to have no problem pulling gas to the carb. Spewed gas out of the filler tube at me, on me actually! I heard the filler opening rumble and thought, what the heck? and it spewed!

hgs_notes · 10-31-2009, 09:22 AM

Probably a pinched vent line. Mine did the same thing after installing a tank. Opened the vent up and it was fine.

**JMac11** · 10-31-2009, 10:06 AM

Did you change the neck from the old tank to the new?

**bigdon-70blazer** · 10-31-2009, 11:01 AM

No, it was a correct fit and application. I could not believe it when I scored it.

**bigdon-70blazer** · 10-31-2009, 05:16 PM

Figured it out, dirt dobbers! Set up house on tank vent tube inlet. I carefull removed it but I will install fuel filter as gas comes out of tank on way to front. Hopefully that will be alright, takes gas like a champ now and it does spit out the cheap stuff!

10-30-2009, 10:37 PM	#1
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Gas tank spewing gas! I got the Blazer fired up tonite! Ran for a while and now we have to do the details but it ran for a while and we shut it off. Not traveling under own but soon. Did do something curious though. Poured gas into the tank and after a short bit, tank rumbled and spewed gas back out the filler. All over me but that is not important. I used another 1969-70 era gas tank after I determined original had leak. Cleaned the one I put in well and replumbed the entire works with new rubber gas lines where needed. Used the old sender unit as it was in pristine condition, only 56K miles on rig. The gas in being pumped from the tank to carb so that works fine. Haven't got enough gas in it to determine if the gauge works yet. Any ideas? I am going to trace down the vent lines tomorrow but thought I would ask. Also, need throttle solution for the new holley 600 carb. I removed the old quadrajet so you know what my linkages looked like originally, they don't work with this set up. Thanks. Starrted after almost 4 years!

10-30-2009, 11:12 PM	#2
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Re: Gas tank spewing gas! sounds like a simple vessel over pressurization. my guess is a clogged/kinked vent tube OR the cap is not allowing proper venting. my old motorcycles had to be able to vent through the cap or bad things would happen. interesting nonetheless. and CONGRATS on the beast roaring to life! give her a kiss from us! __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson Last edited by tcb-1; 10-31-2009 at 09:59 AM.

10-31-2009, 08:01 AM	#3
lks dcvn Registered User Join Date: Jan 2007 Location: Columbus, Ohio Posts: 4,339	Re: Gas tank spewing gas! Is it coming out of the filler tube on the side of the truck - if so - that is some pressure driving the gas out. Did you replace all the lines to/from the tank as well. Vent - 3/8" or 1/2" (can't remember which) Gas Intake line - 1 3/8" (Marine store or Napa might be able to get it) Charcoal Filter line (Might only be on 72 models) - 3/8 or 1/2" (can't remember which) It can be a pain to drop the tank to replace these so hopefully it is still somewhat empty from gas to do this. When I drop the tank I replace all the lines on the tank just to be sure that none of the other lines are problematic/clogged... If after that it is still doing it - try to run it without any other lines on the tank except the one pulling the gas to the carb.

10-31-2009, 08:12 AM	#5
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Re: Gas tank spewing gas! Seem to have no problem pulling gas to the carb. Spewed gas out of the filler tube at me, on me actually! I heard the filler opening rumble and thought, what the heck? and it spewed!

10-31-2009, 09:22 AM	#6
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,122	Re: Gas tank spewing gas! Probably a pinched vent line. Mine did the same thing after installing a tank. Opened the vent up and it was fine. __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

10-31-2009, 10:06 AM	#7
JMac11 Registered User Join Date: May 2005 Location: Tallahassee Fl Posts: 773	Re: Gas tank spewing gas! Did you change the neck from the old tank to the new?

10-31-2009, 11:01 AM	#8
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Re: Gas tank spewing gas! No, it was a correct fit and application. I could not believe it when I scored it.

10-31-2009, 05:16 PM	#9
bigdon-70blazer Registered User Join Date: Jan 2007 Location: Poplar Bluff, MO Posts: 1,501	Re: Gas tank spewing gas! Figured it out, dirt dobbers! Set up house on tank vent tube inlet. I carefull removed it but I will install fuel filter as gas comes out of tank on way to front. Hopefully that will be alright, takes gas like a champ now and it does spit out the cheap stuff!



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