Fuel leak

A fuel leak can occur in many places. There are two types of fuel leaks that should be recognized. Supply leak is a leak from the gas tank or in the fuel lines as the fuel makes its way to the fuel injectors or carburetor. Manifold leak is a leak inside of the engine either from the intake manifold or from the combustion chamber. The supply leak involves a loss of fuel while the engine is off or while it is drawing fuel from the tank. The manifold leak involves a loss of fuel while the engine is on and fuel is being delivered for ignition. A supply leak will show a drop in the fuel level when the engine is not in use, or cause a reduction in engine power as the fuel is not reaching the manifold. A manifold leak, on the other hand, can cause stalling and a reduction in engine power as the fuel escapes the combustion chamber.

Table of Contents

• 1. Symptoms, Supply Leak
  • 1.1 Loss of Fuel
  • 1.2 Gas Smell Outside Vehicle
• 2. Symptoms, Manifold Leak
  • 2.1 Reduction of Engine Power
  • 2.2 Gas Smell Inside Vehicle

Symptoms, Supply Leak

Loss of Fuel

A loss of fuel, particular recognized by a drop in the fuel gauge or a stream of gasoline, is caused by a fuel leak. Depending on the location of the leak, some fuel may be able to stay in the system.

For example, if the leak is near the top of the fuel tank, a vehicle may be operational for a long period of time, as fuel will escape through evaporation and sloshing. There may be a lack of pressure in the tank which will reduce the amount of fuel being picked up by the fuel pump.

A leak lower in the fuel tank, or in the fuel lines, can cause a complete depletion of fuel over a short period of time.

Gas Smell Outside Vehicle

A tell tale sign of a fuel leak is the smell of fuel outside of the vehicle. It should be readily apparent upon approaching the vehicle if there is a leak. If it is a very small leak, the smell may be difficult to detect, but otherwise, it should be easy.

Symptoms, Manifold Leak

Reduction of Engine Power

A fuel leak in the manifold will reduce the power of the engine. The proper proportion of fuel and air will be altered as the fuel escapes the combustion chamber or intake manifold. With less fuel to burn, the engine power will be reduced. This can lead to stalling.

Gas Smell Inside Vehicle

A leak in the manifold will allow fuel to leak out of the engine. The fumes can then be collected in the air as it passes into the passenger cabin. This will produce a fuel smell on the inside of the vehicle. This is hazardous. A car with the smell of fuel on the inside should not be driven.