The cleanliness of oil in a turbo application is extremely important, as implied by the "more frequent" change interval status in the owner's manual. Any "built-up" oil contamination in the lubricating system should be eliminated. That is why the service manual procedure (Section 6J-4, reqarding oil change with a turbo replacement) should be followed.
An often overlooked source of contamination is the turbo oil feed and return lines. A new turbo's bearings can be quickly destroyed by any line contamination.
Before installing a new turbo, both the feed and return oil lines should be checked visually for contamination and by probing with a length of wire. If contamination is suspected, replace the suspect line.
Use applicable labor operation number and labor time.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.