Oil Consumption Test

The amount of oil an engine uses will vary with the way the vehicle is driven in addition to normal engine-to-engine variation. This is especially true during the first 16,100 km (10,000 mi) when a new engine is being broken in or until certain internal engine components become conditioned. Vehicles used in heavy-duty operation may use more oil. The following are examples of heavy-duty operation:
^ Trailer towing applications.
^ Severe loading applications.
^ Sustained high speed or idle operation.

The following is a partial list of conditions that can affect oil consumption rates:
^ Proper maintenance.
^ Engine size.
^ Operator driving habits.
^ Ambient temperature.
^ Quality and viscosity of the oil.

Operation under varying conditions can frequently be misleading. A vehicle that has been run for several thousand miles on short trips or in below-freezing ambient temperatures may have consumed a "normal" amount of oil. However, when checking the engine oil level, it may measure up to the MAX mark on the oil level dipstick due to dilution (condensation and fuel) in the engine crankcase. The vehicle might then be driven at high speeds on the highway where the condensation and fuel boil off. The next time the engine oil is checked, it may appear that a liter (quart) of oil was used in about 160 km (100 mi). This perceived 160 km (100 mi) per liter (quart) oil consumption rate causes customer concern even though the actual overall oil consumption rate is about 2400 km (1500 miles) per liter (quart).

Make sure the selected engine oil meets Ford specification ESE-M2C153-E and the recommended API performance category and SAE viscosity grade as shown in the vehicle Owner Guide. It is also important that the engine oil is changed at the intervals specified for the typical operating conditions.

The following diagnostic procedure is used to determine the source of excessive internal oil consumption:

1. Define excessive oil consumption, such as the number of miles driven per liter (quart) of oil used. Also determine customer's driving habits, such as sustained high speed operation, towing, extended idle and other considerations.

NOTE: Oil use is normally greater during the first 16,100 km (10,000 mi) of service. As mileage increases, oil use generally decreases. Vehicles in normal service should get at least 1,450 km (900 mi) per liter (quart) after 16,100 km (10,000 mi) of service. High speed driving, towing, high ambient temperature and other factors may result in greater oil use.

2. Verify that the engine has no external oil leak as described under Engine Oil Leaks. Engine Oil Leaks
3. Verify that the engine has the correct oil level dipstick.
4. Verify that the engine is not being run in an overfilled condition. Check the oil level at least five minutes after a hot shutdown with the vehicle parked on a level surface. If significantly overfilled, perform steps 5a through 5d.
5. Perform an Oil Consumption Test:
a. Drain the engine oil, remove the oil bypass filter, and refill with one liter (quart) less than the recommended amount.
b. Run the engine for three minutes (10 minutes if cold), and allow the oil to drain back for at least five minutes with the vehicle on a level surface.
c. Remove the oil level dipstick and wipe clean. (Do not wipe with anything contaminated with silicone compounds.) Reinstall the oil level dipstick, being sure to seat the oil level dipstick firmly in the oil level indicator tube. Remove the oil level dipstick and draw a mark on the back (unmarked) surface at the indicated oil level. (This level should be about the same as the MIN mark on the face of the oil level dipstick.)
d. Add one liter (quart) of oil. Restart the engine and allow to idle for at least two minutes. Shut off the engine and allow the oil to drain back for at least five minutes. Mark the oil level dipstick using the procedure above.
e. Record the vehicle's mileage.
f. Instruct the customer to drive the vehicle as usual and:
^ Check the oil level regularly at intervals of 160 to 240 km (100-150 mi).
^ Return to the service point when the oil level drops to the lower MIN mark on the oil level dipstick.
^ Add only full liters (quarts) of the same oil in an emergency. Note the mileage at which the oil is added.

g. Check the oil level under the same conditions and at the same location as in Steps c and d.
^ Measure the distance from the oil level to the UPPER mark on the oil level dipstick and record.
^ Measure the distance between the two scribe marks and record.
^ Divide the first measurement by the second.
^ Divide the distance driven during the oil test by the result. This quantity is the approximate oil consumption rate in kilometers per liter or in miles per quart.

h. If the oil consumption rate is unacceptable, go to Step 6.

6. Check the positive crankcase ventilation (PCV) system. Make sure the system is not plugged.
7. Check for plugged oil drain-back holes in cylinder heads end cylinder block.
8. If the condition still exists after performing the above tests, go to Step 9.
9. Perform a Cylinder Compression Test and/or perform a Cylinder Leak Detection Test with Engine Cylinder Leak Detection/Air Pressurization Kit. This can help determine the source of oil consumption such as valves, piston rings or other areas.
10. Check valve guides for excessive guide clearance. REPLACE all valve stem seals after verifying valve guide clearance.
11. Worn or damaged internal engine components can cause excessive oil consumption. Small deposits of oil on the tip of the spark plugs can be a clue to internal oil consumption. If internal oil consumption still persists, proceed as follows:
a. Remove the engine from the vehicle and place it on an engine work stand. Remove the intake manifolds, cylinder heads, oil pan, and oil pump.
b. Check the piston ring clearance, ring gap and ring orientation. Repair as required.
c. Check for excessive bearing clearance. Repair as required.

12. Perform the Oil Consumption Test to confirm the oil consumption concern has been resolved.