Engine Oil Consumption Diagnosis
OIL CONSUMPTION DIAGNOSISAn engine that has excessive oil consumption uses 0.9L (1 qt.) of oil, or more, within 2,000 mi (3 200 km). The following list indicates the conditions and corrections of excessive oil consumption:
^ An improperly read oil level indicator (dipstick)
- Inspect the oil level while the car is parked on a level surface.
- Allow adequate drain-down time.
^ Improper oil viscosity
- Use the recommended SAE viscosity for prevailing temperatures.
- Refer to Specifications for the proper oil viscosity specifications.
^ Continuous high-speed driving
^ Severe hauling, such as a trailer. This causes decreased oil mileage.
^ A malfunctioning crankcase ventilation system
^ External oil leaks
- Tighten the bolts, as needed.
- Replace the gaskets and seals, as needed.
^ Worn or omitted valve guides and/or valve stem seals
- Ream the guides.
- Install oversized service valves and/or new valve stem seals.
^ Broken or worn piston rings
^ Improperly installed or unseated piston rings
^ Improperly installed or improperly fitted piston
^ Plugged cylinder head gasket oil drain holes
^ Damaged intake gaskets
OIL PRESSURE DIAGNOSIS AND TESTING
LOW OR NO OIL PRESSURE
The following can cause low or no oil pressure:
^ Low oil level - fill to the full mark on the oil level indicator.
^ Slow idle speed
^ Incorrect or malfunctioning oil pressure switch - replace the oil pressure switch.
^ Incorrect or malfunctioning oil pressure gauge - replace the oil pressure gauge.
^ Improper oil viscosity or diluted oil
- Install oil of proper viscosity for expected temperature.
- Install new oil if it is diluted.
^ The oil pump is worn or dirty - clean or replace the oil pump.
^ The oil filter is plugged - replace the oil filter.
^ The oil pickup screen is loose or plugged replace the oil pickup screen.
^ A hole in the oil pickup tube replace the oil pickup tube.
^ Excessive bearing clearance replace the bearings.
^ Cracked, porous, or plugged oil galleries - repair or replace the engine block.
^ The gallery plugs are missing or improperly installed - install or repair as necessary.
^ The pressure regulator valve is stuck.
- Check the pressure regulator valve for sticking in the bore.
- Check the bore for scoring and burrs.
^ The camshaft is worn or poorly machined replace the camshaft.
^ Worn valve guides - repair as needed.
OIL PRESSURE TESTING
- Tools Required
^ J 25087-C Oil Pressure Test Kit
If the vehicle has low oil pressure perform the following tests.
1. Check the oil level.
2. Raise the vehicle and remove the oil filter.
3. Assemble the plunger valve in the large hole of J 25087-C base and the hose in the small hole of J 25087-C base. Connect the gauge to the end of the hose.
4. Insert the flat side of the rubber plug in the bypass valve without depressing the bypass valve itself.
5. Install J 25087-C on the filter mounting pad.
6. Start the engine and check the overall oil pressure, the oil pressure switch, and for noisy lifters. The engine should be at operating temperature before checking the oil pressure. The oil pressure should be approximately 414kPa (60 psi) at 1850 rpm using 1OW30 engine oil.
7. If adequate oil pressure is indicated, check the oil pressure switch.
8. If a low reading is indicated, press the valve on the tester base to isolate the oil pump and/or its components from the lubricating system. An adequate reading at this time indicates a good pump and the previous low pressure was due to worn bearings, etc. A low reading while pressing the valve would indicate a faulty pump.
OIL LEAK DIAGNOSIS