The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-16-2020, 02:17 PM   #1
patroll
Registered User
 
Join Date: Mar 2019
Location: Jackson
Posts: 9
Gas fumes in truck & locking gas cap 1972 Chevy C10

My truck has a strong gas smell after I fill my gas tank on my 1972 Chevy C10, My gas tank has the EEC tubes on the passenger side going into my corner pillar , when you fill the gas tank it is strong and seems to fade away when tank is emptied , also replaced that gas tank hard to find a locking gas cap .
patroll is offline   Reply With Quote
Old 01-16-2020, 06:14 PM   #2
71CHEVYSHORTBED402
Registered User
 
71CHEVYSHORTBED402's Avatar
 
Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,094
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Seems somewhat common a full tank gives off fumes. I can't justify filling the tanks in my Chevys anyway. You might check or replace the rubber hoses, blow out your hard lines where possible, for at least the sake of maintenance.

A 72 gas cap won't fit on your new tank? If it does Napa has a cap for you. My 72 has a locking cap. The fumes are supposed to expand into the canister and out a vented gas cap. You can check the canister too, including the valves.
__________________
Tony
71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s of OEM identifications and part numbers, all written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025
71CHEVYSHORTBED402 is offline   Reply With Quote
Old 01-16-2020, 06:26 PM   #3
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,761
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Also check those rubber lines. They're almost 50 years old, and they tend to crack and leak.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson
truckster is online now   Reply With Quote
Old 01-16-2020, 07:34 PM   #4
lil hoodlum
Registered User
 
lil hoodlum's Avatar
 
Join Date: Oct 2009
Location: Denton, Texas
Posts: 1,688
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

I top off my gas tank every 10 days. No gas fumes. Maybe the gasket under the lock ring on the gas tank is leaking of the hose from the filler neck?
lil hoodlum is offline   Reply With Quote
Old 01-31-2020, 10:51 PM   #5
Kustomkampe
Registered User
 
Join Date: Aug 2017
Location: Independence MO
Posts: 11
Quote:
Originally Posted by lil hoodlum View Post
I top off my gas tank every 10 days. No gas fumes. Maybe the gasket under the lock ring on the gas tank is leaking of the hose from the filler neck?
Can anyone tell me is the 72 with eec gas tank will fit into a 71that has eec?
Posted via Mobile Device
Kustomkampe is offline   Reply With Quote
Old 01-31-2020, 10:52 PM   #6
Kustomkampe
Registered User
 
Join Date: Aug 2017
Location: Independence MO
Posts: 11
Quote:
Originally Posted by Kustomkampe View Post
Can anyone tell me is the 72 gas tank with eec will fit into a 71that has eec?
Posted via Mobile Device
Posted via Mobile Device
Kustomkampe is offline   Reply With Quote
Old 01-31-2020, 11:45 PM   #7
randy500
Account Suspended
 
Join Date: Jul 2016
Location: Tacoma, WA
Posts: 6,873
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Never had any gas fumes in any of my dozens of trucks over the past 35 years.
I would do this if i did.
Pressurize the tank....modify a gas cap to accept an air line fitting, regulate it to 5 psi or so and pressurize the tank.
Use a paint brush with leak detector and look for leaks at all seams and fittings.
randy500 is offline   Reply With Quote
Old 02-01-2020, 12:11 AM   #8
Steeveedee
Who Changed This?
 
Steeveedee's Avatar
 
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,023
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by Kustomkampe View Post
Posted via Mobile Device
If they both had the EEC system, the tank will fit.
__________________
~Steven

'70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper

Simi Valley, CA
Steeveedee is online now   Reply With Quote
Old 02-01-2020, 01:31 AM   #9
Stocker
20' Daredevil (Ret)
 
Stocker's Avatar
 
Join Date: May 2003
Location: Jefferson State
Posts: 13,488
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by 71CHEVYSHORTBED402 View Post
A 72 gas cap won't fit on your new tank? If it does Napa has a cap for you. My 72 has a locking cap.
This. The rubber seal on the cap will rot and fail after several years. Gas will then leak out of a full or near-full tank, especially in right-hand corners.
Mine has only leaked out onto the outside of the tank at the cap, but you can easily smell it inside the cab.
__________________
- Mike -

1972 K20 LWB 350/350/205

RIP El Jay
Stocker is offline   Reply With Quote
Old 02-01-2020, 04:04 AM   #10
Richard
Senior Member
 
Join Date: Dec 1999
Location: Southern California
Posts: 2,666
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Both of my 72"s had a gas smell at times. It was the rubber line from the fuel sender to the hard line near the gas tank. If the rubber fuel lines are original I would recommend replacing them.
__________________
Richard
1972 K10 Custom Deluxe SWB Fleetside
My build https://67-72chevytrucks.com/vboard/...d.php?t=800746
Richard is offline   Reply With Quote
Old 02-01-2020, 04:08 AM   #11
Richard
Senior Member
 
Join Date: Dec 1999
Location: Southern California
Posts: 2,666
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by Steeveedee View Post
If they both had the EEC system, the tank will fit.
Apologize for the high jack. Just wanted to say hello to a fellow Simi Valley 67-72 owner!
__________________
Richard
1972 K10 Custom Deluxe SWB Fleetside
My build https://67-72chevytrucks.com/vboard/...d.php?t=800746
Richard is offline   Reply With Quote
Old 02-01-2020, 04:34 AM   #12
Sheepdip
Senior Member
 
Sheepdip's Avatar
 
Join Date: Nov 2018
Location: Waterford California
Posts: 2,335
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

My Oring seal at the sending unit flange was leaking, replaced it and no more smell from a full tank.
Sheepdip is online now   Reply With Quote
Old 02-01-2020, 09:52 AM   #13
68 P.O.S.
Registered User
 
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,659
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

^^^This! Sending unit gaskets are often the culprit.
__________________
72 C10 lwb fleetside -stock 350/350 combo
68 P.O.S. is offline   Reply With Quote
Old 02-01-2020, 10:32 AM   #14
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,764
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

On my '72 the gas cap has leaked right after a fill up if parked where the driver side sits lower even the slightest bit. Please don't judge me, but it's been that way over ten years. I still fill the truck until the nozzle pops off because it uses gas up so quick. It doesn't leak on turns. The only time it leaks is when I fill it up on my way home not so far away, or close to where I'm going, forget and park it with left side lower. Then I just turn it around. I'm used to it now and I like the Harley caliper emblem I stuck on it ages ago. Silly I guess, but I'm used to it now and act accordingly. I used to forget and sometimes it leaked till the next day. I'd move the truck, light the gravel on fire, and wash that area of the truck. Ever notice the bleached out woodgrain on the driver side cab corner trim of trucks? I replaced mine and the woodgrain survives now. I guess I should get a new cap and say screw the emblem. But I do get a lot of comments on it. More "Hey that's a cool gas cap" than "Hey I smell gas"
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed"

GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project)
GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~
special-K is offline   Reply With Quote
Old 02-01-2020, 11:36 AM   #15
Steeveedee
Who Changed This?
 
Steeveedee's Avatar
 
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,023
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by Richard View Post
Apologize for the high jack. Just wanted to say hello to a fellow Simi Valley 67-72 owner!
right back!
__________________
~Steven

'70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper

Simi Valley, CA
Steeveedee is online now   Reply With Quote
Old 02-01-2020, 12:01 PM   #16
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,764
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

His name is Steve, not Jack
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed"

GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project)
GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~
special-K is offline   Reply With Quote
Old 02-01-2020, 02:18 PM   #17
68 P.O.S.
Registered User
 
Join Date: Jan 2007
Location: Puyallup, WA
Posts: 1,659
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by special-K View Post
His name is Steve, not Jack
__________________
72 C10 lwb fleetside -stock 350/350 combo
68 P.O.S. is offline   Reply With Quote
Old 02-01-2020, 04:59 PM   #18
Steeveedee
Who Changed This?
 
Steeveedee's Avatar
 
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,023
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by special-K View Post
His name is Steve, not Jack
Just don't yell that across the airport concourse!
__________________
~Steven

'70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper

Simi Valley, CA
Steeveedee is online now   Reply With Quote
Old 02-02-2020, 11:49 AM   #19
NewBayColony
Senior Member
 
NewBayColony's Avatar
 
Join Date: Mar 2017
Location: Northbridge,MA
Posts: 493
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

My 72 leaks out of the gas cap ,too. Last summer I filled it up just before I was away for a couple of days. Gas expanded, leaked down the side of the truck and bubbled the paint. Big stain on the driveway, too. Before that leak , I replaced the cap with 2 different brands of repops. Supposedly the correct caps for a 72 3/4 ton without smog equipment. Still leaked. I don't fill it up as much now but I would like to know if anyone has found a solution to this.
__________________
72 C20 292 3OTT
77 GMC 2500 4x4 Longstepper 350 4sp
50 3100 ex Airforce/Town of Mendon fire truck
72 GMC 1500 2wd short stepside 250 4sp
78 GMC 2500 4x Longstepper 292 4sp
54 6400 Chevy 5 window 4 sp 2sp vac rear end Shell oil truck/dump truck (Norman)
NewBayColony is offline   Reply With Quote
Old 03-07-2020, 03:52 PM   #20
Mike_The_Grad
Senior Member
 
Mike_The_Grad's Avatar
 
Join Date: Oct 2013
Location: Santa Paula, CA
Posts: 576
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

I use the Stant locking gas cap for 72 w/eec. I have also removed the smog/emissions stuff and just have my tank vented to atmosphere under the cab where the vapor return line would normally connect to the frame mounted vapor line. No issues with smell in around or under the cab. Eventually the rubber under the cap gets cracked and starts giving up the liquid gold down the side of the cab. So I replace it. I'm on cap number 5 in the last 6 years. The ethanol in today's gas is tough on rubber parts.
__________________
1972 C/10 LWB - Mine
1964 C/10 LWB - My Dad's

Instagram: Mike_The_Grad
Mike_The_Grad is offline   Reply With Quote
Old 06-17-2020, 07:53 PM   #21
External
Registered User
 
External's Avatar
 
Join Date: Jun 2018
Location: Louisiana
Posts: 186
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Looking for suggestions.
So far I have replaced all the lines, rubber and stainless.
The tank, the gasket on the tank. I siliconed the gasket also.
The only part of the lines I didn't replace was the vent lines inside the pillar.
Are those metal? If not that might be the culprit.
Oh and i am using the Stant locking vent cap for the 72 with EEC
I filled up the tank to almost full today and it's worse.
It's pretty dang bad. Bad enough i am already putting a price tag on how much i would pay for someone to fix it.
If anyone could help it would make me super happy.
Thanks for listening
__________________
'72 Chevy Custom Deluxe Highlander. Med Olive/White 350/200 ps,pb and Air Conditioning!
External is offline   Reply With Quote
Old 06-17-2020, 10:19 PM   #22
57taskforce
All about them K’s
 
57taskforce's Avatar
 
Join Date: Jun 2014
Location: Farmington, New Mexico
Posts: 6,170
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

The lines in the passenger side cab corner are steel. I’ve filled my truck up twice in the last week and a half with no issues with smell/leaks. I don’t have eec though.
__________________
Tyler
'57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888
'72 K20 Cheyenne http://67-72chevytrucks.com/vboard/s...d.php?t=662879
‘69 K10 SWB http://67-72chevytrucks.com/vboard/s...d.php?t=805206
'98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's
‘87 IROC-Z all original 50K mile survivor TPI 305 IROC Blue
‘10 Camaro 2SS/RS Aqua Blue Metallic #93 -version 2.0

Last edited by 57taskforce; 06-17-2020 at 10:51 PM.
57taskforce is online now   Reply With Quote
Old 06-17-2020, 10:44 PM   #23
External
Registered User
 
External's Avatar
 
Join Date: Jun 2018
Location: Louisiana
Posts: 186
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

I just pulled my locking Stant gas cap and its rubber was cracked pretty bad.
I put the original cap back on. Will see it that helps tomorrow.
__________________
'72 Chevy Custom Deluxe Highlander. Med Olive/White 350/200 ps,pb and Air Conditioning!
External is offline   Reply With Quote
Old 06-18-2020, 09:04 PM   #24
External
Registered User
 
External's Avatar
 
Join Date: Jun 2018
Location: Louisiana
Posts: 186
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Well, put the original gas cap back on. And smell is gone.
Thank you all for your posts
__________________
'72 Chevy Custom Deluxe Highlander. Med Olive/White 350/200 ps,pb and Air Conditioning!
External is offline   Reply With Quote
Old 06-18-2020, 11:51 PM   #25
scrapmetalart
Junior Member
 
Join Date: Mar 2007
Location: DAYTON
Posts: 505
Re: Gas fumes in truck & locking gas cap 1972 Chevy C10

Quote:
Originally Posted by Sheepdip View Post
My Oring seal at the sending unit flange was leaking, replaced it and no more smell from a full tank.
this is the first place id check. i just replaced mine and cleaned some rust scale off the tank where the o ring sits. much better now
__________________
frontstreetcycle on Instagram
scrapmetalart is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:37 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com