The bore in the cylinder head for the N3 EUI is directly through the cylinder head water jacket. To prevent coolant from contaminating the injector and still maintain maximum cooling of the injector, a stainless steel tube is screwed into the injector bore. The tube has a O-ring installed to create a water and gas-tight seal.
It is recommended that the injector tube be replaced with new a O-ring at the time of engine over haul. The injector tube is reusable.
Do not remove the injector tube for inspection unless a fault in the tube is suspected.
Removal of the Injector Tube
Perform the following steps to remove the injector tube: