Diesel fuel is closer to oil than it is to gasoline. It too has a distinctive odor, and also feels slick between your fingers like oil does. Diesel is not as volatile as gasoline, but you still need to address a diesel fuel leak sooner rather than later.
Diesel fuel works best under pressure. Diesel engines use this high pressure in their fuel systems to atomize the fuel when it’s injected into the combustion chamber. This is the heart of the system, really. If there’s a loss of pressure or there’s air in the fuel system, the engine won’t run. So if you have a diesel fuel leak and your engine won’t start, repair the fuel leak, bleed the air from the system, and try again.
In addition to the fuel tank, fuel lines, and fuel filters, diesels also have a fuel distributor. This distributor sends fuel to the correct cylinder at the correct time. You could say the fuel distributor is the brains of the operation when it comes to fuel delivery on a diesel engine. That said, the fuel distributor is another possible leak source. In addition to leaking externally, it can also leak internally. If this happens, it can cause the engine not to start or run properly. Also, diesel engines can have external fuel pumps or more than one fuel pump in their systems. These fuel pumps are also potential leak sources. The fuel system on a diesel is very important to its operation, so any leaks you find in the system should be addressed ASAP.