1. Remove top cover and oil cap.
2. Undo the oil filter but dont remove so the oil filter drains. (saves mess later)
3. Raise vehicle and remove skid plate
4. Remove drain plug and drain the oil (drain pan needs to hold at least 12 quarts)
5. After the oil drains, replace drain plug with new washer and tightened to 30 NM.
6. Lower vehicle and put 5 quarts in the oil filter housing and the rest in the oil filler. This is to prevent crankshaft damage.
NOTE : it is very important not to spill any oil around the oil filler as the alternator is directly below and oil can damage it.
7. Replace oil filter cartridge and install the new seals that came with the filter. See T.S.B http://www.wkjeeps.com/tsb/tsb_wk_0900507.pdf
Slightly oil the new seals and reinstall the filter into the oil filter housing and tightened to 25 NM.
8. It is now critical to wait 15 minutes before starting to allow the oil to drain down. Service manual also say wait 15 minutes after engine has run to allow the oil to return to the pan before checking the oil level.
OIL SAE VISCOSITY GRADE
An SAE Synthetic engine oil that conforms to ACEA A3/B4/C3 that is approved to MB 229.31 low ash oil
OIL CAPACITY 10.0 Quarts
Drain plug torque 22 ft-lbs
Oil filter 18 lbs-ft with oil filter socket 9551