Dark Oil or Sludge

• When the Jeep Liberty oil has not been changed in a long time or after heavy use, the oil filter stops filtering debris from the oil and it becomes dark with particles. These particles cause wear on engine parts. In extreme cases, the oil becomes sludge and clogs oil passages.
  
  

Milky or Watery Oil

• Water drops in oil or milky oil is a symptom of a potentially more serious engine problem. A blown cylinder gasket, cracked cylinder head or engine block is allowing water to leak into the oil system. The engine needs to be checked as soon as possible.
  
  

Low Oil Levels

• Low oil levels are a symptom of an oil leak. A leaky seal, broken gasket or worn piston rings or valve guides all could be the cause. If the piston rings are worn, the low oil levels may be accompanied by smoky exhaust.