Clean the gasket sealing surfaces on the oil drain line and the turbocharger.
Clean the o-ring seating bore in the cylinder block, taking care not to drop any dirt and debris into the cylinder block.
Clean the turbocharger oil drain line with solvent and dry with compressed air.
Inspect the oil drain line for any signs of coking or restriction.
Clean the inside of the oil drain line if it shows signs of oil coking or restriction.
Inspect the oil drain line for signs of cracks, wear, or other damage. Replace the oil drain line if these signs are present.
Inspect the drain line sealing o-ring for signs of cracks, wear, or fretting. Replace as necessary.
