Fuel Degradation
Gasoline begins to break down and lose its volatility after about 3–6 months (even faster with ethanol blends). Old fuel becomes gummy and sticky, which can:
- Clog fuel lines, filters, and injectors
- Make starting the engine difficult or impossible
- Reduce combustion efficiency
2. Water Contamination
Over time, condensation can form inside a sitting fuel tank, especially if it's not full. This introduces water into the fuel system, which:
- Can cause rust inside the tank and lines
- Leads to poor engine performance
- May trigger corrosion in fuel system components
3. Sludge and Varnish Buildup
Old fuel leaves behind residues that gum up critical components:
- Fuel pumps and injectors can seize or clog
- Carburetors (on older vehicles) may become unusable
- The fuel filter will get overwhelmed quickly
4. Engine Damage
Trying to run an engine on degraded fuel puts stress on the fuel delivery system and can cause misfires, knocking, or even internal damage from poor lubrication or inconsistent combustion.
Why It’s Important to Clean the Fuel Tank
Remove Contaminants
If a car has been sitting for months or years, it’s likely to have rust flakes, sediment, or sludge at the bottom of the tank. Flushing the tank ensures these don’t get pulled into the fuel system.
Restore Fuel System Health
A clean tank:
- Protects the fuel pump
- Prevents clogging in fuel filters and injectors
- Supports smoother engine startup and consistent performance
Prevent Costly Repairs
Replacing a fuel pump, injectors, or even the engine due to contaminated fuel can cost hundreds or thousands of dollars. A proper fuel system cleaning is a small investment that avoids major repairs.