I have a 2001 Z3 2.5i automatic. Yesterday I started it and the red oil pressure light came on before I exited the garage so I turned it off, checked the oil level and found it to be down - probably at least a liter. This is unusual because for the three years I've owned it it hasn't used any oil. This morning I checked the oil and it was right at the full level. Hmm! Turned it on for 30 seconds until the oil pressure light came on, turned it off, checked the oil and it was low again. Ideas please - thanks.