No, you should never put aviation gasoline (AVGAS) in a car's fuel tank. While it might seem like just another type of gasoline, AVGAS is formulated specifically for piston-engine aircraft and is fundamentally incompatible with modern automotive engines. Using it will likely cause immediate and severe damage to your car's emission control system and can lead to costly engine repairs.
The primary issue is the lead content. AVGAS, particularly the common 100LL (Low Lead) grade, contains tetraethyl lead, an additive that protects aircraft engines but is extremely harmful to cars. This lead will quickly contaminate and destroy the catalytic converter, a critical emissions component, and can foul the oxygen sensors. Furthermore, AVGAS has a different octane rating system. Its 100/130 octane (a measure of a fuel's resistance to knocking) is not directly equivalent to the pump gasoline you use. While high, it's not optimized for a car's engine control computer, potentially leading to poor combustion and performance issues.
The following table outlines the key differences that make AVGAS a poor choice for automobiles:
| Fuel Property | Aviation Gasoline (AVGAS 100LL) | Standard Automotive Gasoline (Unleaded) |
|---|
| Lead Content | High (Tetraethyl Lead) | None (Unleaded) |
| Primary Use | Piston-engine Aircraft | Modern Automobiles |
| Octane Rating | 100/130 (Aviation Scale) | 87, 89, 91-93 (AKI/MON Scale) |
| Impact on Catalytic Converter | Destructive (will clog and ruin it) | Safe and Compatible |
| Additives | Formulated for high-altitude operation | Contains detergents for fuel injectors/valves |
Beyond mechanical damage, using AVGAS in a road vehicle is illegal in the United States as it violates the Clean Air Act due to its leaded composition. If you accidentally misfuel, do not start the engine. The safest course of action is to have the car towed to a repair shop to have the fuel tank drained and flushed completely to prevent any damage.
