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Questions and Answers

Chevrolet Corvette Stingray Gas Fumes

Q. Mr. Ciulla, I recently purchased a matching numbers 1972 Chevrolet Corvette Stingray. It has the original 350 small block and automatic transmission. I'm not sure what type of carburetor it has but it's a two barrel carburetor. The previous owner explained that I should let the engine warm up before I get it going and that I should check the oil level after every fill up.

Chevrolet Corvette Stingray Gas Fumes

He explained that it didn't leak oil but due to it's age it would probably burn it a little. He had recently had the timing chain and distributor replaced. I've since added a can of engine restore and that seems to have helped a little. I intend to rebuild the engine and increase it's performance.

It's in great running condition but I've noticed that after I store it in the garage, it gives off a very strong gasoline odor. Also when I drive it and apply the brakes it pulls to the left. I assume I need to get the right side brakes bled, but the strong gas odor concerns me. My other vehicle which is also kept in the same garage, is beginning to smell like gas when I get in it too.

If I air out the garage by leaving the garage door up for a while the odor goes away. But as soon as I close it the odor starts to get stronger and stronger. It's getting to the point that the house hallway entrance into the garage is also starting to smell.

The car starts and runs good and I've noticed that there is a small amount of oil on the garage floor but I can't see how that small amount can cause such a strong odor. It's almost as if I had left the gas tank open and it's evaporating into the air. Which consequently, I check the gas gauge and I don't see any large drop in gas level.

I run it on the weekends only so if the gas was evaporating I would assume I'd notice a drop in gas level. With your experience in automobiles can you explain what can cause the strong odor or what I can do to rule out any possibly causes?

Thank you,
Jordi

A First of all, I would NOT park it in the garage until we find out why there is such a strong gas smell.

There's a few possibilities for the gas smell. First, and most likely, is a fuel leak. I would jack up the car, support it with jack stands so it won't fall on you, and visually inspect the fuel tank, metal fuel lines and flexible fuel lines right up to the carburetor. The gas tanks on this car were prone to corrode through in the area of the attaching straps and seam.

Another possibility is a bad or cracked charcoal canister. The charcoal canister is supposed to absorb fuel fumes from the fuel tank and release them into the intake when the engine is running. I'm assuming, at this point, it does have a properly functioning gas cap.

Another possibility is the carburetor. There is a fuel bowl vent that comes up through the air filter housing, inside the air filter. If it has a stock air filter housing assembly, any fumes should be trapped inside the air filter. But with it sitting for a week or two at a time the fumes may seep out through the air filter material and into the atmosphere.

You may have a bad fuel pump also. The diaphragm may be ruptured and fuel could be leaking either out of the fuel pump or into the crankcase. Maybe that is why the previous owner made sure to tell you to let the engine warm up and check the oil often? Not that it is a bad recommendation, but why state the obvious?

You probably won't notice a drop in fuel level. A very small amount of gasoline can make a lot of fumes.

As for the brakes, you could very well have a bad right side disc brake caliper or collapsed right side brake hose. If that is the case, I would recommend replacing both front brake calipers, flexible brake hoses and brake pads. I also recommend having the front rotors resurfaced or replaced if they are under specification. In short, a complete front brake job.

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