The 1-11129064-1 Injector Sleeve (Nozzle Holder) is a critical sealing component for the ISUZU 6WG1 engine, commonly found in heavy-duty trucks (such as the Isuzu Giga, C&E series) and industrial applications.
What It Is
This part is often called an injector sleeve, injector cup, or nozzle holder sleeve. It sits inside the cylinder head and seals the fuel injector nozzle from the combustion chamber and the engine coolant passages. The assembly typically includes the sleeve itself, a copper washer (or sealing ring), and sometimes an O‑ring for coolant sealing.
Function
Seals combustion gases inside the cylinder.
Prevents coolant from entering the fuel system or cylinder.
Ensures proper injector alignment and heat transfer.
Common Failure Symptoms
When the injector sleeve fails (due to corrosion, cracked O‑ring, or improper installation), you may experience:
Hard starting or misfiring.
White smoke (steam) from the exhaust.
Coolant loss with no visible external leak.
Fuel dilution of coolant or coolant in the fuel.
Excessive crankcase pressure.
Replacement Notes
Special tools are required (sleeve puller/installer, reaming tools) to avoid damaging the cylinder head.
Always replace the sleeve O‑rings and copper washers as a set.
Use the correct torque for the injector hold‑down bolt (refer to the engine service manual).
After installation, a coolant pressure test is recommended to verify the seal.
