Gas Smell - The 1947 - Present Chevrolet & GMC Truck Message Board Network

PitterPats72 · 12-10-2002, 02:50 PM

I have been smelling gas fumes in my truck cab. I check the hoses in the cab today and none look like they are leaking but could they be letting the fumes seep into the cab. Or is there a charcoal canister (like in my VW) near the gas tank?

thanks,
pat

694X4 · 12-10-2002, 02:57 PM

I think some of the tanks are vented and some are not but I could be wrong. I think if the gas cap gets pluged up it will stink inside the cab.

*Randy70C-10* · 12-10-2002, 02:57 PM

Did you check to make sure that your carb isn't leaking?

stllookn · 12-10-2002, 03:10 PM

My '67 and '68 were both vented into the cab on the passenger side. Check to see if you have hose from the tank leading up in the corner of the cab on the passenger side...it is a vent!

Lippyp · 12-10-2002, 03:13 PM

Check your gas cap, I had the same problem and it turned out to be the seal in the cap had gone porous, it was fine if the tank was low but when you filled up it would start stinking after about 10 minutes. The fuel slopping about was soaking through the seal and leaking out around right hand bends. One new gas cap, no further smells.

**1971Stepside** · 12-10-2002, 03:30 PM

I hope you don't smoke!!! Step away from the truck before lighting up....

Long Knight · 12-10-2002, 03:39 PM

I hear that smoking covers up that gas smell really well!LOL

Seriously though,
Got an unvented locking cap by mistake, caused all kinds of problems. On long trips I would get a high vacuum in my tank and loose power from lack of fuel. On warm days sitting in the sun, as my cab warmed up the vapor in the tank , and with no where to vent, would expand and push fuel out of every hole and orifice of my carb, and all over the engine. I drilled a tiny hole in the top of the rubber gasket of the locking cap and haven't had a problem since.

70c10 · 12-10-2002, 05:04 PM

It's your O-ring at the fuel sending unit probably.

rusty ol' 69' · 12-10-2002, 07:37 PM

No no no it's the muffler bearings they're thrashed. You better buy a new set. The flow through kind. Sorry I'm bored here.

Longhorn Man · 12-11-2002, 12:17 AM

In 71, they added some kind of loop made of rubber line up inbetween the inner and outer cab wals on the passenger side. (over where the stock jack should be) This was supposed to only be on the 71/72 trucks, but I have seen a 69 so equipped, and stillookin says he had a 67 and 68. Look up in there and stick your nose in there to see if the fumes are stronger up there.
If this seems OK, then slide your seet al the way forward and look to see if you can see any traces of fuel coming from the sending unit seal.
If that is good, look at the filler neck going into the tank.
These are the most common places for the fuel vapor to be coming from.

Long Knight · 12-11-2002, 10:05 AM

I don't have a vent hose on mine, just a vented cap.

Brewski* · 12-11-2002, 10:41 AM

If you have more than one tank, i.e. saddle tanks and have a controle valve to switch tanks on these can leak gas also. I am trying to find a new one right now so mine does not smell anymore.

PitterPats72 · 12-11-2002, 10:49 PM

Will ck tomorrow.

Looked at the hoses and they look a little "dry" may be them.

Did not see any sign of leakage at sending unit.

Thanks,
Pat

**BIG ORANGE** · 12-11-2002, 11:01 PM

I had the same problem with the 69 and a new gas cap done the job,know more gas smell.

12-10-2002, 02:50 PM	#1
PitterPats72 Registered User Join Date: Oct 2001 Location: Indianapolis, IN Posts: 145	Gas Smell I have been smelling gas fumes in my truck cab. I check the hoses in the cab today and none look like they are leaking but could they be letting the fumes seep into the cab. Or is there a charcoal canister (like in my VW) near the gas tank? thanks, pat __________________ 72 Chevy Custom 10 Deluxe (78K mi.) 95 Nissan Maxima (195K mi.) 73 VW Beetle (owned since 78; 96K miles) Engine rebuild by me done! 73 VW Super Beetle -New to me- Bought from original owner! 84 Honda Nighthawk (2500 mi.) I know too much foreign stuff; I've owned American too and they lasted just as long.

12-10-2002, 02:57 PM	#2
694X4 Registered User Join Date: Jul 2001 Location: utica, oh, Posts: 249	I think some of the tanks are vented and some are not but I could be wrong. I think if the gas cap gets pluged up it will stink inside the cab. __________________ 69 3/4 ton 4x4 gmc with 6" sky jacker soft ride. 350 / th350 / 205 work in progress

12-10-2002, 03:10 PM	#4
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	My '67 and '68 were both vented into the cab on the passenger side. Check to see if you have hose from the tank leading up in the corner of the cab on the passenger side...it is a vent! __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

12-10-2002, 03:13 PM	#5
Lippyp English Chevy Owner Join Date: May 2002 Location: Shropshire, UK/ Lot, France Posts: 1,848	Check your gas cap, I had the same problem and it turned out to be the seal in the cap had gone porous, it was fine if the tank was low but when you filled up it would start stinking after about 10 minutes. The fuel slopping about was soaking through the seal and leaking out around right hand bends. One new gas cap, no further smells. __________________ Phil '67 C10 long fleet. 350/TH350, 4 bbl Carter, K&N, Dual exhaust, loads of stuff coming soon 2001 S10 Blazer Daily Driver, bone stock 4 door 4x4 with manual transmission

12-10-2002, 03:30 PM	#6
1971Stepside Almost Satisfied Join Date: Mar 2002 Location: Springfield, MO Posts: 2,932	I hope you don't smoke!!! Step away from the truck before lighting up.... __________________ 1971 C10 Stepside. LSx 6.0 with BTR Stage IV, Speed Engineering Headers, 4L80e transmission w/3200 Circle-D Stall. 3.73. Posi. Purchased this truck when I was 17. I started the rebuild (or take apart) in 1993. I have drug it around all over the country in pieces. Finally back on the road in 2021. "I can't complain, but sometimes I still do. Life's been good to me so far."

12-10-2002, 02:57 PM	#3
Randy70C-10 Account Suspended Join Date: Mar 2001 Location: Virginia Beach, Va. U.S.A. Posts: 15,320	Did you check to make sure that your carb isn't leaking?

12-10-2002, 03:39 PM	#7
Long Knight Spank 'em if you got 'em! Join Date: Nov 2002 Location: Kansas City Posts: 628	I hear that smoking covers up that gas smell really well!LOL Seriously though, Got an unvented locking cap by mistake, caused all kinds of problems. On long trips I would get a high vacuum in my tank and loose power from lack of fuel. On warm days sitting in the sun, as my cab warmed up the vapor in the tank , and with no where to vent, would expand and push fuel out of every hole and orifice of my carb, and all over the engine. I drilled a tiny hole in the top of the rubber gasket of the locking cap and haven't had a problem since. __________________ Long Knight '71 C-20, 350ci, TH350, Edl. 1406 Carb w/elec.choke, Ignitor ignition, Viper Tires, Orange Dipstick

12-10-2002, 05:04 PM	#8
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	It's your O-ring at the fuel sending unit probably. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

12-10-2002, 07:37 PM	#9
rusty ol' 69' Grubbin' Join Date: Aug 2002 Location: Chico, CA Posts: 293	No no no it's the muffler bearings they're thrashed. You better buy a new set. The flow through kind. Sorry I'm bored here. __________________ project rust attack 1969 Chevrolet LWB w/ 307. I got power steering now woohooooo!!!!!!!

12-11-2002, 12:17 AM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	In 71, they added some kind of loop made of rubber line up inbetween the inner and outer cab wals on the passenger side. (over where the stock jack should be) This was supposed to only be on the 71/72 trucks, but I have seen a 69 so equipped, and stillookin says he had a 67 and 68. Look up in there and stick your nose in there to see if the fumes are stronger up there. If this seems OK, then slide your seet al the way forward and look to see if you can see any traces of fuel coming from the sending unit seal. If that is good, look at the filler neck going into the tank. These are the most common places for the fuel vapor to be coming from.

12-11-2002, 10:05 AM	#11
Long Knight Spank 'em if you got 'em! Join Date: Nov 2002 Location: Kansas City Posts: 628	I don't have a vent hose on mine, just a vented cap. __________________ Long Knight '71 C-20, 350ci, TH350, Edl. 1406 Carb w/elec.choke, Ignitor ignition, Viper Tires, Orange Dipstick

12-11-2002, 10:41 AM	#12
Brewski* Registered User Join Date: Aug 2001 Location: Rocky Mount, MO Posts: 1,293	If you have more than one tank, i.e. saddle tanks and have a controle valve to switch tanks on these can leak gas also. I am trying to find a new one right now so mine does not smell anymore.

12-11-2002, 10:49 PM	#13
PitterPats72 Registered User Join Date: Oct 2001 Location: Indianapolis, IN Posts: 145	Will ck tomorrow. Looked at the hoses and they look a little "dry" may be them. Did not see any sign of leakage at sending unit. Thanks, Pat __________________ 72 Chevy Custom 10 Deluxe (78K mi.) 95 Nissan Maxima (195K mi.) 73 VW Beetle (owned since 78; 96K miles) Engine rebuild by me done! 73 VW Super Beetle -New to me- Bought from original owner! 84 Honda Nighthawk (2500 mi.) I know too much foreign stuff; I've owned American too and they lasted just as long.

12-11-2002, 11:01 PM	#14
BIG ORANGE Senior Member Join Date: Oct 2001 Location: Lancaster S.C. Posts: 4,767	gas smell I had the same problem with the 69 and a new gas cap done the job,know more gas smell. __________________ Things happen for a reason!



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