Pinpoint Test A: Excessive Engine Oil Consumption
- Possible Sources
- Gasket
- Seal
- Blocked or restricted turbocharger oil drain pipe
- Damaged or collapsed air intake hoses and tubes
- Turbocharger oil seals
- Inoperative PCV system
- Incorrect engine oil
- Worn valve stem seal
- Worn valve stem or valve guide
- Sticking piston ring
- Worn piston ring groove
- Damaged oil control ring
- Worn piston or cylinder
- A1 CHECK FOR ACCEPTABLE ENGINE OIL CONSUMPTION
- Carry out the engine oil consumption test REFER to: Oil Consumption Test
Is engine oil consumption in the acceptable range?
Yes The vehicle is operating correctly. No GO to A2 - A2 CHECK FOR PCM (POWERTRAIN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Carry out the PCMKOEO and KOER self-tests.
Are any Diagnostic Trouble Codes (DTCs) present?
Yes REFER to the Master DTC Chart to diagnose the DTC present. No GO to A3 - A3 CHECK FOR EXTERNAL ENGINE OIL LEAK
- Ignition OFF.
- Inspect the engine for signs of engine oil leaks. REFER to: Oil Leak Inspection
Are any engine oil leaks visible?
Yes REPAIR as necessary. No GO to A4 - A4 CHECK THE VEHICLE SERVICE HISTORY
- Check the vehicle service history and make sure the correct engine oil used is documented.
Is the correct engine oil used based on the vehicle service history?
Yes GO to A5 No CHANGE the engine oil and filter using the correct engine oil specification. Refer to the Specifications procedure in the appropriate engine article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure. - A5 CHECK THE AIR INTAKE SYSTEM
- Inspect the air intake system and make sure all of the hoses and tubes are securely connected and free of damage.
Is the air intake system free of damage and all of the connections correctly secure?
Yes GO to A6 No REPAIR as necessary. - A6 CHECK THE PCV (POSITIVE CRANKCASE VENTILATION) SYSTEM
- Inspect the PCV system and make sure all of the hoses and tubes are securely connected, free of damage and the PCV valve operates correctly.
Is the PCV system free of damage, all of the connections correctly secure and the PCV valve operating correctly?
Yes GO to A7 No REPAIR as necessary. - A7 CHECK FOR ENGINE OIL IN THE COOLING SYSTEM
- Check for engine oil in the cooling system.
Is engine oil detected in the cooling system?
Yes If equipped with an engine oil cooler, GO to A8 If not equipped with an engine oil cooler, GO to A11 No If equipped with a turbocharger, GO to A9 If not equipped with a turbocharger, GO to A11 - A8 CHECK THE ENGINE OIL COOLER
- Inspect the engine oil cooler and seals for damage.
Are the engine oil cooler and seals free of damage?
Yes GO to A9 No REPAIR as necessary. - A9 CHECK THE TURBOCHARGER(S)
- Inspect the turbocharger(s) for indication of an oil seal leaking in to the air intake or exhaust system. REFER to the Diagnosis and Testing procedure in the appropriate Fuel Charging and Controls article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure.
Are the turbocharger(s) leaking oil into the intake or exhaust?
Yes REPAIR as necessary. REFER to the Removal and Installation procedure in the appropriate Fuel Charging and Controls article for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure. No GO to A10 - A10 CHECK THE SPARK PLUGS
- Inspect the spark plugs for signs of oil fouling. REFER to: Spark Plug Inspection
Do the spark plugs or pistons have oil deposits or show signs that the engine is burning oil?
Yes GO to A11 No The source of the concern is not the engine. Check for other possible sources for oil consumption. Re-check for acceptable oil consumption. Check the PCV system and turbochargers. - A11 CHECK THE CYLINDER HEAD GASKET, CYLINDER HEAD AND ENGINE BLOCK DECK SURFACES
- Remove the cylinder head(s). Inspect the cylinder head gasket, cylinder head and cylinder block for damage. REFER to: Cylinder Block Distortion . and REFER to: Cylinder Head Distortion
Is the cylinder block and cylinder head(s) free of damage?
Yes GO to A12 No REPAIR as necessary. - A12 CHECK THE VALVE STEM SEALS
- Remove the cylinder head(s). Remove the valves from the cylinder heads and inspect the valve stem seals for damage, excessive wear and proper sealing.
Are the valve stem seals damaged?
Yes Install new valve stem seals. REFER to the Disassembly and Assembly of Subassemblies - Cylinder Head procedure for the engine being diagnosed. Refer to the appropriate Engine system article for the procedure. No GO to A13 - A13 CHECK THE VALVE TRAIN
- Inspect the valves for excessive oil or carbon build up. Inspect the valves, valve stems and valve guides for damage. REFER to: Valve Guide Inner Diameter . REFER to: Valve Stem Diameter
Are the valves damaged or do they show excessive wear?
Yes INSTALL new valve seals, valves or a new cylinder head. No GO to A14 - A14 CHECK THE ENGINE
- Disassemble the engine. Check the pistons and piston rings for excessive carbon build up. Check the pistons, piston rings and cylinder bores for excessive wear or damage. REFER to: Piston Inspection . REFER to: Piston Ring End Gap . REFER to: Cylinder Bore Taper
Is damage, excessive wear or excessive carbon build up found on the pistons or piston rings?
Yes REPAIR as necessary. No INSTALL a new short block.