In diesel injectors, there are very serious faults that — if they happen and aren’t fixed quickly — can damage the engine completely and lead to a full overhaul.

Here are the most important problems you must watch out for:

The Most Dangerous Diesel Injector Failures That Can Destroy the Engine

1 — Injector Stuck Open

This is the most dangerous failure of all.

When the injector stays open, it causes:

• Excess fuel injected into the cylinder
• Engine oil becomes diluted with diesel → the oil loses its viscosity
• High temperatures
• Wear of the cylinder walls and piston
• The engine may start accelerating uncontrollably (runaway)

Result: broken pistons — bent connecting rods — full engine overhaul.

2 — Weak or Cutting Injector (Low Pressure / Misfire)

When the injector doesn’t deliver fuel properly:

• Incomplete combustion inside the cylinder
• Abnormally high temperature
• Wear in the cylinder head
• Knocking inside the engine

Result: damaged piston or burnt valve.

3 — Internal Injector Leakage

Internal leakage causes:

• Excess return fuel to the return line
• Weak injection pressure
• Unburnt fuel entering the cylinder → slowly damages the piston over time

Result: cracked piston crown or worn piston edge.

4 — Late Injection

This causes:

• High exhaust temperature
• Excess load on the turbocharger
• Overheating of the cylinder head

Result: cracked cylinder head or blown head gasket.

5 — Injection Too Early

Early injection causes:

• Loud ticking noise
• Very high pressure on the piston
• Severe diesel knock

Result: broken piston rings — damage to connecting rods.

6 — Injector Seat Leak

If the injector seat isn’t tightened properly or has debris:

• Blow-by around the injector
• Extreme heat around the injector
• Erosion of the seat area in the cylinder head

Result: new cylinder head or welding required → high repair cost.

Warning Signs Your Injectors Are About to Damage the Engine

• Very dark black smoke
• Misfiring or vibration
• Unusual fuel consumption
• Engine oil smells like diesel
• High engine temperature
• Loud ticking noise
• Noticeable loss of power

The car accelerates on its own (DANGER!!!)