General Procedures - Oil Consumption Check

1. 1
   Nearly all engines consume some oil, which is necessary for normal lubrication of cylinder walls, pistons and rings. To determine the oil consumption rate, testing may require recording how much oil is added over a specified number of miles.
2. 2
   Customer driving style greatly affects oil consumption. Mileage accumulated while towing or under heavy loads generates additional heat. Frequent short trips, stop-and-go driving or prolonged idling, which prevents the engine from reaching normal operating temperature, also affect consumption. This does not allow clearances between components to reach specified operating ranges.
3. 3
   The following diagnostic procedure can be used to determine internal oil consumption. Make sure the concern is related to internal oil consumption and not external leaks, which also consume oil. Verify there are no leaks before performing the test. After the test, internal oil consumption can be checked.
4. 4
   A new engine may require additional oil during early operation. Internal piston-to-bore clearances and sealing characteristics improve as the engine breaks in. Engines are designed with close tolerances and do not require break-in oils or additives. Use the oil specified in the Owner's Literature. Ambient temperature may determine the oil viscosity specification. Make sure the correct oil is used for the vehicle in the geographic region where it is operated.

Basic Pre-Check

1. 1
   For customer complaints of oil consumption, interview the customer to determine oil consumption characteristics. If possible, determine the brand and grade of oil currently in the crankcase. Check the oil filter label or oil change station records to determine whether the Ford-recommended maintenance schedule was followed. Make sure the oil was changed at the specified mileage intervals. If vehicle mileage exceeds the first recommended change interval, the OEM (original equipment manufacturer) production filter may have been changed.
2. 2
   Ask how the most recent mileage was accumulated. This helps determine whether the vehicle was operated under the following conditions:

   Visual Inspection Chart

   
   

   • Prolonged engine idling or idling on the shoulder
   • Stop-and-go or taxi operation
   • Towing a trailer or heavily loaded vehicle
   • Frequent short trips (engine not warmed up to normal operating temperature)
   • Excessive throttling or high engine speed driving
3. 3
   Make sure there are no external leaks. If necessary, review the diagnostic procedure in this section.
   For additional information, refer to: Oil Leak Check (303-00 Engine System - General Information, General Procedures).
4. 4
   Inspect the crankcase ventilation system for:

   Visual Inspection Chart

   
   

   • disconnected hoses at the valve cover or TB.
   • loose or missing valve cover oil filler cap.
   • missing or incorrectly installed engine oil dipstick.
   • incorrect or dirty PCV valve.
   • PCV valve grommet not installed in the valve cover (if equipped).
5. 5
   Inspect for signs of sludge. Sludge affects PCV performance and can clog or restrict the cylinder head drain passages. It can also increase oil pressure by restricting passages and reduce the ability of the piston oil control rings to drain. Sludge may form either from excessive water entering the crankcase or from operating at very high crankcase temperatures.
6. 6
   Inspect the air filter for dirt, sludge or damage. A hole in the filter element will allow unfiltered air to enter the air intake system. This can cause premature internal wear (engine dusting), which allows oil to leak past the rings, pistons, valves and guides.
7. 7
   If the engine is hot or has recently been shut off, wait at least 15 minutes to allow the oil to drain back. Ask the customer if this requirement was observed. Adding oil without this waiting period may cause an overfill condition, resulting in excessive oil consumption and foaming, which can damage the engine.
8. 8
   Make sure the oil level indicator (dipstick) is correctly and fully inserted into the indicator tube. Remove the oil level indicator and record the oil level.

Detailed Preliminary Checks

1. 1
   Check the thermostat opening temperature to make sure that the cooling system operates at the specified temperature. If it is low, the internal engine components will not operate within the specified internal operating clearances.
2. 2
   Make sure the spark plugs are not saturated with oil. Oil leakage into one or more cylinders will appear as an oil-soaked condition on the plug. If a spark plug is saturated, a compression test may be needed upon completion of the oil consumption test.

Oil Consumption Test

1. 1
   Drain the engine oil and remove the oil filter. Install a new oil filter specified by the manufacturer. Make sure the vehicle is on a level surface. Fill the oil pan to one quart (liter) below the specified fill level, using the oil specified by the manufacturer.
2. 2
   Run the engine for 3 minutes (if hot) or 10 minutes (if cold). Allow a minimum 15-minute drain-back period, then record the oil level shown on the oil level indicator. Mark the back of the oil level indicator at the oil level position.
3. 3
   Add the last quart (liter) to complete the normal oil fill. Restart the engine and let it idle for 2 minutes. Shut down the engine.
4. 4
   After the 15-minute drain-back period, record the oil level position again. Mark the oil level indicator at the new oil level position. (Note: both marks should be very close to the MIN and MAX upper and lower limits, or the upper and lower holes on the oil level indicator. These marks will accurately measure engine oil consumption, with a difference of one quart between the new marks.) Show the customer that the factory calibration marks on the oil level indicator are where the oil should drop after an oil change with the specified fill amount. Explain, however, that this may vary slightly between the MIN and MAX or the upper and lower holes of the oil level indicator.
5. 5
   Record the vehicle mileage.
6. 6
   Inform the customer that the oil level indicator readings must be checked every 320 km (200 miles) or weekly, using the revised markings as shown. Remind the customer that the engine requires a minimum 15-minute drain-back for accurate readings, and that the oil level indicator must be fully seated in the tube before taking readings.
7. 7
   When subsequent indicator readings show that one full quart (liter) has been consumed, record the vehicle mileage. The mileage must be at least 4800 km (3000 miles) for standard vehicles and 800 km (500 miles) for Ford Performance vehicles. The driving cycle in which the vehicle was operated must be taken into account in this calculation. The customer may need to bring the vehicle in for periodic oil level indicator readings to closely monitor oil consumption.

Follow-Up Checks, Evaluation and Corrective Actions

1. 1
   If the test results indicate excessive oil consumption, perform a cylinder compression test. The cylinder compression test should be performed with a fully charged battery and all spark plugs removed. Refer to the Compression Test Specifications table in this section for range limits.
2. 2
   Compression should be equal in all cylinders. If compression is within the specifications in this section, excessive oil consumption may be related to worn valve guides, valves or valve stem seals.
   For additional information, refer to: Compression and Cylinder Leakage Test (303-00 Engine System - General Information, General Procedures).
3. 3
   A cylinder leakage test can be performed using a cylinder leak detector. This can help identify worn valves, piston rings, valve guides/valve stems, failed valve stem seals or other related areas as the source of oil consumption.
   For additional information, refer to: Compression and Cylinder Leakage Test (303-00 Engine System – General Information, General Procedures).
4. 4
   If internal engine damage is isolated as the root cause, determine whether the repair will exceed cost limits, and proceed with a repair strategy as required.
5. 5
   After completing the corrective actions on the engine and verifying that all pre-check items have been cleared in the original diagnosis, repeat the oil consumption test as described above and check the consumption results.