Check as follows:
- Inspect the intake air hoses for oil.
- If oil is present, inspect the air filter and replace if it is clogged.
- If oil is not present, go to the next step.
- Remove the exhaust pipe before the ATD and inspect for oil in the exhaust.
- Remove the large clamp at the APT which will enable moving the inner stage duct to see inside the duct..
- If no oil is found, inspect the APT air solenoid. If the air pressure is correct, replace the APT.
- If oil is found, remove the turbocharger and exhaust manifold, go to the next step.
- Inspect the exhaust ports for signs of oil.
- If there are signs of oil, troubleshoot for internal oil consumption caused by valve guides or worn cylinders, liners, and rings.
- If the exhaust manifold has no signs of oil, replace the turbocharger. Refer to "4.2 Turbocharger"
in the “Air Intake System” chapter of the EPA07 DD15 Workshop Manual