Many times when the HPDI Cylinder Head Side Gasket pictured below are removed for injector service, not much attention is paid to the orientation of the gaskets until the new ones need to be installed. When the injectors are removed from the cylinder head, the old injector gasket material needs to be cleaned from the cylinder head pockets and from the injector nozzles.
Twelve new injector gaskets can be purchased in a powerhead gasket kit or ordered individually. Why do I need 12 gaskets when I only have 6 injectors? Simple, each injector needs two gaskets.
The HPDI Cylinder Head Side Gasket are different on each side. Which way do they go? There is a metal reinforcement ring in the center of the gasket with a wide flange on one side and a narrow flange on the other. The two narrow (smaller) flanges face each other; the wide flanges contact the cylinder head surface and the injector body.
To complete the job make sure the injector packing is in good condition, and then install the injectors with gaskets, and fuel rails. Torque the bolts for the injector holders and the fuel rails to spec. Finish off by running the motor again to check for any fuel or air leaks.