Absolutely not. Brake fluid is a highly corrosive substance that does not belong in a fuel tank under any circumstances. Introducing brake fluid into your vehicle's fuel system will cause severe and costly damage.
Why Brake Fluid is Catastrophic for Your Fuel System
The primary reason brake fluid is so damaging to a fuel system is its chemical composition and its interaction with materials not designed to withstand it.
- Corrosive Nature: Brake fluid, particularly the glycol-based types (DOT 3, DOT 4, DOT 5.1), is hygroscopic, meaning it absorbs moisture. More importantly, it is formulated to handle the high temperatures and pressures of a braking system, but it is highly aggressive towards rubber and plastic components found in a fuel system. The provided reference explicitly states that brake fluid is "highly corrosive."
- Seal Swelling and Damage: A critical point highlighted in the reference is that brake fluid "will swell seals and cause damage." Fuel systems rely on various rubber and plastic seals, O-rings, and hoses to maintain integrity and prevent leaks. When brake fluid comes into contact with these materials, it causes them to swell, soften, and degrade rapidly, leading to fuel leaks, pressure loss, and component failure.
Potential Damage to Your Vehicle
The consequences of putting brake fluid in a gas tank extend far beyond just the fuel tank itself. The entire fuel delivery system, and potentially the engine, are at risk.
Components at Risk:
- Fuel Tank Lining: Many fuel tanks have internal coatings that can be degraded.
- Fuel Pump: Seals and internal components of the fuel pump will be compromised, leading to pump failure.
- Fuel Lines: Rubber and plastic fuel lines will soften, crack, and potentially burst.
- Fuel Filter: The filter material can break down, sending debris further into the system.
- Fuel Injectors (or Carburetor): Delicate seals within injectors will swell, leading to improper fuel delivery, leaks, and potential engine misfires. In carbureted engines, gaskets and internal parts will be damaged.
- Engine Components: If contaminated fuel reaches the engine, it can damage oxygen sensors, catalytic converters, and even internal engine components due to improper combustion and corrosive residue.
What to Do If Brake Fluid Enters Your Gas Tank
If you have mistakenly put brake fluid into your gas tank, it's crucial to act immediately to minimize damage.
| Action Item | Description |
|---|---|
| DO NOT Start the Engine | Starting the engine will circulate the corrosive fluid throughout the entire fuel system, exponentially increasing the damage and repair costs. Even turning the ignition to the "on" position without starting can activate the fuel pump and begin circulation. |
| Isolate the System | If possible, disconnect the battery to prevent any accidental activation of fuel pumps or other electrical components. |
| Call for Professional Assistance | Contact a qualified mechanic or roadside assistance immediately. Explain exactly what happened. |
| Tow the Vehicle | Your vehicle must be towed to a repair shop. Do not attempt to drive it or even move it under its own power. |
| Fuel System Flush and Inspection | A professional will need to drain the entire fuel tank, flush the entire fuel system thoroughly, and inspect all components (fuel pump, lines, filters, injectors) for damage. Depending on the extent of contamination, component replacement may be necessary. |
Mixing automotive fluids is a common mistake that can have dire consequences. Always double-check the fluid you are pouring into your vehicle's reservoirs to avoid expensive and preventable damage. Brake fluid is designed for the braking system only, and its properties are entirely incompatible with a vehicle's fuel system.
