After replacing a turbocharger, what must be done before starting the engine to ensure lubrication?

• A. Prime with oil
• B. Block the compressor wheel from turning
• C. Lubricate the turbine wheel fins
• D. Lubricate the compressor wheel fins

Answer: (A)

Priming with oil ensures the turbo’s bearing system is filled and pressurized before the engine starts. The turbo relies on a steady oil supply to lubricate its journal bearings and seals; without this initial oil film, the first rotation can occur with dry bearings, leading to accelerated wear or seizure. The other options aren’t how lubrication is provided in a turbo: blocking the compressor wheel from turning is a handling precaution, not a lubrication step, and lubricating the turbine or compressor wheel fins isn’t how the bearing surfaces are treated—oil lubricates the bearings, not the wheel fins.