Oil Level And Muddiness

WARNING: This page is about a different car, the 2004 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

Ensure the vehicle is on a level surface with engine off, then check the oil level. If the engine is already started, stop it and allow 10 minutes before checking.
Check that the oil level is within range.

Fig 1: Oil Level Range On Dipstick
Courtesy of NISSAN MOTOR CO., U.S.A.
If it is out of range, add oil as necessary. Refer to RECOMMENDED FLUIDS AND LUBRICANTS .
Check the oil for contamination.
If the oil is white, it is highly probable that it is contaminated with coolant. Diagnose the problem and correct as necessary.