Depends on where the oil leaks from , normally a cloudy or "grey" oil sheen ,oozing out from here and there doesnt consern me too much , but now the oil running from the big hole or crack in the housing now that conserns me , make sure unit is "primed" with water (small flow from tip with motor off but hose turned on) if still no good then cycle your unloader a few times by tunring the pressure adjustment all the way up and all the way down with water on and motor runninng , this should work unless you have a larger problem