kryan5732

Hi again. So I have a gas smell in my 66. All I have read on this forum suggests I use a VENTED gas cap which is what I have. It is a new one from Corvette Central. However, according to an article I have "Getting The Smell Out" by John Hinckley (not the Reagan shooter), he opines and I quote "Either the tank or the cap must be vented in order to allow air to replace the volume of fuel as it's used- but not both". Since I have the rubber vent from the tank, do I need a vented cap or a non-vented? Thank you experts. PS My mechanic did not find any unusual leaks when he gave it the once over.

Sky65

The rubber hose coming from the gas filler neck boot is a drain. If that is the hose you are talking about. It is not a vent for the tank. If you spill gas while filling the tank, or water enters the boot around the filler lid, it will drain down that hose at the rear of the car.

Tom

DansYellow66

Have you noticed if the smell is worse when you have an almost full tank of gas? The cork gasket between the fuel tank and the filler pipe commonly leaks. I had to use 2 baskets back-to-back to get mine to seal up when I replaced the tank. On a hot surface, a couple drops of leaked gas will stink like you dumped a full quart of fuel on the floor. So when checking fuel lines and carb hookups, look really closely.

DZVette

You should have a vented cap. As Tom pointed out above that hose is for draining away fuel overflow captured by the rubber boot surrounding the filler neck. Also, as Dan pointed out, the fuel filler neck gasket is a common leakage spot. It's just a thin cork gasket. It's a fairly easy fix. The neck is held by nine screws with their own rubber seals. Be careful working around the fuel filler area. NO SPARKS!



Do a search about the filler neck gasket. Good tips have been posted.
Dave Z

Jackfit

Hi, as a 46 yr owner , follow suggestions, but get use to it. Our cars carry the smell of combustion inside and out and on you. They are 50 year old gas burners.....and some of us endure and love it.

Wait a few years and see

Jackfit

vark_wso

GM SERVICE replacement fuel tanks sold for 63-74 Corvettes include an integral pressure-vacuum valve. GM provides instruction that when these tanks are used to replace tanks on 1963-69 Corvettes, the vented fuel cap should be replaced with a non-vented (70-74 style) cap. Perhaps you have such a tank ...

If you have a convertible, it's fairly easy to see if your tank is a GM replacement with this pressure relief valve. It's located to the left (driver's side) of the filler neck on top of the tank. With a (tightly held!) dental mirror poked through the filler neck into the tank, look for a quarter-sized valve protrusion through the top of the tank maybe 4" left of the filler neck. Alternately, if you remove the rubber filler neck seal on a coupe or convertible, you can see the presence or absence of such a valve as it's visible on the exterior/top of the tank.

Use a sealed '70-'74 gas cap if you have such a replacement tank & your fuel smell will be greatly reduced. However, as DansYellow mentions, the cork gasket between the tank top and filler neck flange is quite often a smell-contributing device.

tuxnharley

Yup - I'm one year behind ya, Jack - but agree 100%!

Frankie the Fink

After much work, neither my '61 or '63 coupe will befoul passengers with that sickly fuel smell -- nor does it get in the cockpit. There is no reason it should. As stated check the gasket at your fuel filler neck and ensure your overflow hose is OK. Also the black toilet plunger rubber dome around the filler neck can crack. If you replace the filler neck gasket get new screws for it. They have an "O" ring around them and yours are certainly shot if the gasket is.

Bluffman

I had that gas smell 67 conv, changed out the fill neck cork, the flange on the neck was bent from over tightening I presume, hammered it flat, installed new cork with some rtv and no more smell. Very easy repair. Ian

JohnZ

If you'll re-read the title page of my article, you'll see that the subject matter was C-1 Corvettes, which required non-vented gas caps. The '63-'67 Corvette fuel system design is completely different, and requires a VENTED cap.

kryan5732

Yes, I finally did see that! Thanks all for the suggestions. I have never filled the tank yet, but I will soon. It is beautiful here in Denver so I need to take it for a ride tomorrow!

vark_wso

... unless the OPs original tank was replaced at some point on/after CY 1969 with an integral-vent GM service replacement 3967746 (Group 3.001); many were, including my '66. Then, per Note 1, non-vented cap 3994339 (Group 3.028) applies.

kryan5732

I looked inside tank and it looks original. No sign of pressure relief valve.


When I walked into the garage to check I did not smell gas. Maybe I just don't remember what these old cars smelled like!

Jackfit

While my car is being fixed, painted from pole crash.....I had the opportunity to replace my broken sending unit and also the cork gasket on the filler neck.

As you can see from the photos...the old cork is shot and you can see the spilled gas on the tank top.

The tank is an NOS replacement , provided by Forest Chevy Dealer in Maine . It may have been replaced be me in 2004 or 1982 both years I did restoration....look at the labels .

The sending unit may be original to the car....tab broke when body shop removed wires...I am installing a new unit. I may restore old one.

Will replace straps and anti squeak cork and new bolts and brackets.

Jack

kryan5732

Thanks Jackfit and everyone else. I'm taking the ole '66 to Corvette's Only (Denver)tomorrow. For $100 they will check all numbers and I will mention the smell. I finally got all my stuff to wash my car with the two bucket wash system. How could I not have known how to was a car correctly after 63 years!

buns

My '66 always had a gassy smell, could never find the source until I removed the tank. I found several pin sized rust holes under the strap rubbers. The rest of the tank was pristine.

Jackfit

Here is the installation of the new sending unit. Not hard , just be patient and take photos before you take things apart. You need to squeeze the float in a bit to get through hole.

You can use the special tool to remove and install or just a screwdriver if careful.

Jack

Jackfit

Here is the installation of the cork gasket. You should, (must) use new screws with rubber seals. I will also put a new rubber seal , nipple , hose with spring to complete the task.

I have new straps , bolts and anti squeak pads ready to go.

kingwoodvette

Is that circular thing to the left of the filler opening the vent that has been discussed? Since you said you had replaced the tank during one of your two previous restorations, it should satisfy the post 1969 date noted earlier.

DansYellow66

I believe so as my GM replacement tank I purchased about 1990 has the same plug there. I believe I understood it was for a vent for some C3 models.