Engine Oil: Service and Repair

ENGINE OIL CHANGE

CAUTION: Do not use oil filter with metric threads. The proper oil filter has SAE type 3/4 X 16 threads. An oil filter with metric threads can result in oil leaks and engine failure.

All Jeep engines are equipped with a high quality fullflow, throwaway type oil filter. Daimler-Chrysler Corporation recommends a MOPAR or equivalent oil filter be used.
Change engine oil at mileage and time intervals described in Maintenance Schedules.
Run engine until achieving normal operating temperature.
1. Position the vehicle on a level surface and turn engine off.
2. Hoist and support vehicle on safety stands.
3. Remove oil fill cap.
4. Place a suitable drain pan under crankcase drain.
5. Remove drain plug from crankcase and allow oil to drain into pan. Inspect drain plug threads for stretching or other damage. Replace drain plug if damaged.
6. Install drain plug in crankcase.
7. Position a drain pan under the oil filter.
8. Using a suitable oil filter wrench loosen filter.





9. Rotate the oil filter counterclockwise to remove it from the cylinder block oil filter boss or filter adapter housing (Fig. 68).
10. When filter separates from adapter nipple, tip gasket end upward to minimize oil spill. Remove filter from vehicle.





11. Make sure old gasket comes off with oil filter. With a wiping cloth, clean the gasket sealing surface (Fig. 69) of oil and grime.
12. Lightly lubricate oil filter gasket with engine oil or chassis grease.
13. Thread filter onto adapter nipple. When gasket makes contact with sealing surface, (Fig. 69) hand tighten filter one full turn, do not over tighten.
14. Lower vehicle and fill crankcase with specified type and amount of engine oil described in this section.
15. Install oil fill cap.
16. Start engine and inspect for leaks.
17. Stop engine and inspect oil level.

CRANKCASE OIL LEVEL INSPECTION

CAUTION: Do not overfill crankcase with engine oil, oil foaming and oil pressure loss can result.

The engine oil level indicator (Dipstick) is located at the right rear of the 4.0L engine. Inspect engine oil level approximately every 800 kilometers (600 miles). Unless the engine has exhibited loss of oil pressure, run the engine for about five minutes before checking oil level. Checking engine oil level on a cold engine is not accurate.
To ensure proper lubrication of an engine, the engine oil must be maintained at an acceptable level.





The acceptable levels are indicated between the ADD and SAFE marks on the engine oil dipstick (Fig. 70).
1. Position vehicle on level surface.
2. With engine OFF, allow approximately ten minutes for oil to settle to bottom of crankcase, remove engine oil dipstick.
3. Wipe dipstick clean.
4. Install dipstick and verify it is seated in the tube.
5. Remove dipstick, with handle held above the tip, take oil level reading (Fig. 70).
6. Add oil only if level is below the ADD mark on dipstick.

USED ENGINE OIL DISPOSAL
Care should be exercised when disposing used engine oil after it has been drained from a vehicle engine. Refer to the WARNING at beginning of this section.