Part No. MAN, Rev. 1-0809 Check the engine oil level. Figure 6-14. Check the engine oil level using the dip- stick (gas engine shown). • Spray lubricant (WD-40 or equivalent) into the pressure relief valves on the filter canister. Push the valves in several times while spraying to fully lubricate them. Figure 6-15. Spray lubricant on the pressure relief valves.