The Hitachi SIDI system used on some LF1 3.6L V6 and LAF 2.0L ECOTEC has two seals in the injector tip. These seals must be installed into their grooves, and then sized to the engineered dimension before the injectors are installed into their bores in the cylinder head. There are two seal installation pilots included in GM-49245 (one for each groove), which allow the seal to slide onto the injector tip without catching on any machined surface or the incorrect groove. GM-49245 also includes a seal installer to drive the seal over the pilot and into the groove, and a sizer to compress each seal into its groove and ensure its size before installation. GM-49245 must be used to install the seals correctly and to ensure they are sized correctly for leak-free operation.

Please note that some 2013 or newer injectors from Bosch, Continental, and Delphi have slightly larger injector tips and require the protector ramps from the GM-51105 Injector Seal Installer Adapter set.  These are used with the installer and sizer from GM-49245.