There is nothing more annoying than finally getting your Mustang engine tuned so it runs right, to find out that your girlfriend doesn’t want to ride in it anymore because it smells like gasoline.
In truth, this is a common problem with older cars. To some extent, it’s normal: your car doesn’t have a catalytic converter, so it will always be smellier than a modern-day vehicle. However, in some cases action has to be taken: you don’t want to be driving around with stinging eyes and have your clothes smelling like a gas station after a leisurely drive.
If your Mustang smells like gas while driving, here are a couple of things you can try.
How to fix a gas smell in your Mustang
- check if the smell comes from the engine, the exhaust, or the fuel system
- Engine: check the carburetor float level and mix
- Exhaust: check the integrity of the exhaust system
- Fuel system: check gas tank, filler neck and gas lines
Read on for a detailed explanation of each step…
Finding the origin of the smell
For starters, we have to consider two types of smells: does the car smell like gas, exhaust, or both? If it smells like gas, use masking tape to cover the seam between the hood and the cowl grille, and the cowl grille itself. This will help to determine whether the smell is coming from the engine or the interior.
In any case, there are a number of potential problem areas to check:
- Gas tank and filler neck, gas lines
- Exhaust system
Checking the engine
- Check the float level on your carburetor. If the float is set too high, fuel might splash on top of the carb and evaporate.
- Check the air/fuel mix on your carburetor: a rightly tuned carburetor can cause a strong gas smell. A rich adjustment of your carb will also result in black, sooty exhaust and blackened spark plugs.
- Check the engine oil cap. If the O-ring is worn, fuel fumes can escape from the engine.
Checking the exhaust system
If there are any holes in your exhaust system, exhaust fumes might find their way into the car’s passenger compartment. Check the integrity of the entire exhaust system.
Checking the fuel system
In order to ensure the fuel system is intact and leak-free, check the gas tank, gas tank filler neck and gas lines. Even a tiny hole in the gas tank or a bad connection between the filler neck and the gas tank can cause a strong gas smell. In case of doubt, test any potential problem areas by covering them with duct tape.
Pro tip: the small rubber hose that connects the filler pipe to the gas tank is often the root of the problem. Make sure the clamps are on tight as well.
Update: I finally tracked down the gas smell in my own ’65 Mustang. There was a small, almost imperceptible gas leak where the throttle linkage meets the carb. Every time the accelerator was pushed (and the throttle linkage turned), a small amount of gas would leak out of the carb and onto the engine block. With the engine hot, this gas would instantly evaporate. In the end, I opted to switch out the carb for a new one, which insta-fixed the problem.
Did these tips solve the gas smell in your classic Mustang? Leave a comment and let us know!