The effect of O-rings in the fuel injector is that they act as sealing rings to prevent diesel leakage from the connection points in the injector, especially at the fuel inlet and outlet.

If the O-rings become damaged or worn out, they lose their ability to provide a tight seal, allowing diesel to leak from the injector in an undesired manner.

This leads to nozzle dribbling (fuel leakage) outside the correct injection timing.

As a result, fuel consumption increases and the accuracy of fuel injection into the combustion chamber decreases, causing reduced engine performance, black smoke, increased vibrations, and misfires during the combustion process.

Continuous fuel leakage increases the chances of engine damage and reduces the lifespan of injectors.

These leaks may occur either by leaking diesel into the combustion chamber or leaking into the engine oil.

Leaking into the combustion chamber…

But when diesel leaks into the engine oil, it causes the oil to lose its viscosity properties, reducing its ability to prevent friction and cool the engine — which has a destructive effect on the engine.