C1 Gasoline Odor Removal

If you own a Classic Corvette you probably can smell gasoline when you drive your car.  Why put up with that when a few easy fixes can get rid of that gasoline odor.

Here are a few areas where you should concentrate first.  Remember, gasoline fumes can ignite with explosive results and can cause major damage to your Corvettes interior areas and even the fiberglass body of the car if it is unchecked.

Always disconnect the battery when working on the fuel system.  One spark at the wrong time and you will experience a small Hiroshima.

Carburetor

Safety first: Let’s look at the Carburetor and the fittings between the fuel pump and the carb too.  This is the area that is constantly moving when the car is running and taking some fantastic number of shocks as you drive over our bumpy roads.  Ensure that the carb is properly torqued to the Intake Manifold. Also, inspect the body of the carb for any seal leaks.  Classic Corvettes came with steel fuel lines with flared fittings.  If yours has any rubber hoses in the line, remove them and replace them with the standard fuel lines or make your own from approved replacement lines available at all auto parts counters.  There are also some classic carb setups that have a tapered pipe thread on either side of the fuel filter and at the fuel entrance to the carb itself.  A light application of Teflon pipe “dope” however is recommended for all the fittings, yes even the flared fittings.  Yeah, I know they don’t really seal but they allow you to easily tighten the flared fittings and help eliminate damage to the threads and the flared ends during tightening. 

Caution:  Do NOT use Teflon tape on ANY gasoline fitting.  The tape has a tendency to shred and fine strips could break away and become lodged within the filter (if you’re lucky) or in the carb itself. 

Fuel Pump

If your fuel pump shows any indication of a leak, i.e., “wet spots” or dried stains, you need to either replace or if it’s original, rebuild the pump.  Before you go to that trouble, though, check all the connections to ensure that they aren’t the source of the leak.  Wipe the entire pump with a non-flammable cleaning solution so that you will be able to see, upon further inspection, where the fuel seems to be coming from.  This is a good time to replace the flexible fuel line if there is any indication of a leak there. 

Tip:  The flexible fuel line deteriorates from the inside, so if you haven’t replaced yours within the last five (5) years, it’s probably a good idea to do so.  They are available through most catalogue vendors.

The remaining area of concern is everything in the fuel system that surrounds the gasoline tank within the car.

Gas Cap

1953 – 1956 Corvettes utilized vented gas caps.  They weren’t outfitted with a gas tank vent hose.  1957 – 1962 Corvettes utilized non-vented gas caps and WERE outfitted with a gas tank vent hose.  If you are a purist, stick with the correct gas cap for your Corvette.  If not, you may want to install a vent line and get a non-vented gas cap.  Either way, the gas tank must be vented to allow your fuel system to function properly.

Tank Cover Panel Seal

This is a simple one.  The fiberglass panel that helps to form the bottom of the Convertible Top Boot covers the Gas Tank.  You will notice that it is secured with numerous screws.  Most Classic Corvette panels that screw directly into fiberglass are at best loose.  This is normally due to fiberglass holes that are too big to accept the screws any longer (See Tip following this section).  Once you take out all of the screws securing the panel to the boot bottom, you can turn the panel over and see the brittle material that has deteriorated and is no longer sealing.  You can usually find auto parts stores that will carry “dum-dum”.  This is a black tar sticky substance that was universally utilized by the auto companies for sealing.  Get some and lay a strip of the dum-dum around the entire perimeter of the Tank Cover Panel when you replace it.  This material usually stays pliable for many years.

Tip: You can purchase small tapered plastic anchors that are color coded red.  These will usually solve the problem of securing panels into old fiberglass holes. 

While you have the Fuel Tank Cover off the car, you will want to check out the following areas for leaks too.

Fuel Filler Hose

This is a short section of “fuel filler hose” that is specially made to withstand gasoline.  It is located between the filler neck (metal) that protrudes from the body within the Fuel Filler Cavity and connects this filler neck with the fuel tank.  This rubber connection is necessary for vibration isolation.  It is often deteriorated and/or dry rotted.  Access is gained through the gas tank fiberglass cover at the bottom of the convertible top storage area.  The hose is very thick, hard to access and thus difficult to seal.  Use extra care and ensure that the two clamps are very tight. 

Caution: If you need to replace the fuel filler hose, be sure to replace it with “fuel filler hose”.  You can order this through most Corvette Catalogs and you can usually find generic fuel hose at most auto parts stores, sold by the foot.

Gas Tank Vent

Who would ever purposefully put a hole in a gas tank?  Well if you don’t have a vent somewhere in this part of your system, you will not be able to move gasoline to the carb via the fuel pump.  Air has to replace all that gasoline you use.  Sometime late in the 1956 run of Corvettes the General decided to stop utilizing a vented gas cap (probably because of the gasoline smell in the cockpit area) and rely on a vent line that penetrates the gas tank near/at the fuel sending unit opening.  So if you already have a vent line, you do not need, nor should you want, a vented gas cap.  You will always get a gasoline smell in your Corvette cockpit especially with the top up and the windows closed.  But then, who in their right mind wants to drive a Corvette that way anyhow.  So get rid of that vented gas cap if you don’t have to have it.  Remember, your gas tank must be vented either at the gas cap or via a vent hose. 

Tip: When you run the vent line across the top of your gas tank, it should be routed through a hole into the Fuel Filler Cavity.  This hole is supposed to have a grommet that will allow the hose a snug fit.  The vent hose takes a 90 degree turn down and terminates inside the Fuel Filler Cavity.  It is held in place by a small clip.  DO NOT ROUTE THE VENT HOSE INTO THE FUEL FILLER CAVITY AND THEN OUT THROUGH THE DRAIN OPENING.  This will hamper and possibly cut off fuel overflow from properly draining to the ground.  Tree huggers may love you for it, but you may have a fire and burn your plastic fun machine.

Sending Unit

The Gas Gauge relies on a sending unit that is located inside the Fuel Tank.  This sending unit is installed through a large hole in the top of the gas tank.  The sending unit cover is secured with 5 bolts.  Also attached to this cover is a wire that connects the sending electrically to the Gas Gauge on the dash cluster.  Between the cover and the tank is a large gasket.  If the area around the gasket is dry and not stained with fuel residue, the gasket is probably OK.  If this is not the case, you should replace it.  It will no doubt be a catalog item, i.e., Eckler’s, Corvette Central, etc). 

Tip: This is a good time to add a secondary ground wire from one of the sending unit bolts and run the wire along the path of the gasoline line to a location where it can be secured via a bolt/screw to the frame.  This will stop electrical interference with the gas gauge.  For instance when you step on the brake and the gas gauge takes a nose dive.  Or when you turn on the turn signal and the gas gauge needle bounces with the rhythm of the flasher.  This is because the ground for the rear wiring harness is usually not adequate to stop this from happening. 

Hood Seal

I saved this for last because it’s always been a big question mark to me.  Why did the General only put a rubber seal on the rear of the engine hood?  Well, it was to stop the rush of hot and sometimes foul smelling air that is constantly being forced through the grille, through the radiator and across the engine; from blowing up and over the windshield as you drive with the top down or directly into the cowl vent if it is open.  If this seal is in poor condition, replace it.

Tip: 3M makes a black weatherstrip cement that is fantastic.  After removing the old weatherstrip and the old cement (completely) apply the 3M cement to both the hood and the weatherstrip, let them dry until tacky and apply.  This is best done with the help of a friend.

Storage Smells

Even if everything is working properly and all the gaskets, seals, etc. are fully sealed, the gas tank vent and the carburetor will release gas odors when your Corvette is sealed up in a bag or under a cover.  To get rid of this problem, gently shove a golf tee into the vent line and cover the horn of the carb with some plastic wrap.  I like to seal the plastic wrap with a large rubber band around the carb air horn.

Caution: Don’t forget to remove the plastic wrap and the golf tee in the Spring or whenever you uncover your Corvette.