Test

The following diagnostic procedure is intended to be used to determine the source of excessive internal oil consumption:
1. Define excessive oil consumption such as how many miles are driven per quart of oil. Also determine owner's driving habits such as sustained high-speed operation, towing, extended idle and other factors.

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

2. Verify engine has no external oil leak as described under Engine Oil Leaks.
3. Verify engine has 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. The oil level should never be above the top of cross-hatch area and "F" in FULL. If significantly overfilled, perform Steps 5a through 5d.
5. Perform an oil consumption test:
a. Drain engine oil. Replace oil bypass filter and refill with one quart less than recommended.
b. Run the engine for three minutes (10 minutes if cold) and allow oil to drain back for at least five minutes with vehicle on level surface.
c. Remove engine oil level dipstick and wipe clean. (Do not wipe with anything contaminated with silicone compounds.) Reinstall oil level dipstick and 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 ADD mark on the face of the oil level dipstick.)
d. Add one quart of oil. Restart the engine and allow to idle for at least two minutes. Shut off the engine and allow oil to drain back for at least five minutes. Mark the oil level dipstick using the procedure above. (This level may range from slightly below the top of the cross-hatched area to slightly below the letter "F" in FULL.)
e. Record vehicle's mileage.
f. Instruct the owner to drive the vehicle as usual and:
(1) Check the oil level regularly at intervals of 160-240 km (100- 150 miles).
(2) Return to the service point when the oil level drops below the lower (ADD) mark on the oil level dipstick.
(3) Add only full quarts of the same oil in an emergency and 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.
(1) Measure the distance from the oil level to the UPPER mark on the oil level dipstick and record.
(2) Measure the distance between the two marks and record.
(3) Divide the first measurement by the second.
(4) Divide the distance driven during the oil test by the result. This quantity is the approximate oil consumption rate in Kilometers Per Liter (KPL) or Miles Per Quart (MPQ).

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

6. Check PCV valve system. Make sure system is not plugged.
7. Check for plugged oil drain-back holes in cylinder heads and cylinder block.
8. If the condition still exists after performing the above tests, go to Step 9.
9. Perform a Compression Test, and/or an Oil Leak and Valve Guide Seal Test as described, with Rotunda Pressurization Kit 014-00705 or equivalent. This can help to 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.

NOTE: After checking for worn parts, determine which parts should be replaced. Use correct parts.

11. Worn or damaged internal engine components can cause excessive oil consumption. Small deposits of oil on tip of spark plugs can be a clue to internal oil consumption. If internal oil consumption still persists, proceed as follows:
a. Remove engine from vehicle and place it on Rotunda Engine Stand 014-00232 or equivalent. Remove intake manifolds, cylinder heads, oil pan and oil pump.
b. Check piston ring clearance, ring gap and ring orientation. Service as required.
c. Check for excessive bearing clearance. Service as required.

12. Perform oil consumption test as described to confirm oil consumption concern has been resolved.