I changed my engine oil today (now 4500 mile intervals with Synthetic). Before I sucked the oil out, I checked the engine oil level. It was below the MIN mark. In fact, it was almost to the very bottom of the dipstick (the red rubber part). I know my oil level light works, because when i drained the oil, and turned ignition to position 2, the OIL light did come on.

First question, how low does the oil have to get for the light to come on? Maybe the sender unit is a little out of line or something?

Secondly, I have always noticed a small amt of oil consumption, I do check it periodically, but probably hadn't in 2k or more miles. I am assuming since my longer oil change intervals (4500, before it was 3000), that is why it seems there is more oil loss. Also, really drive my car hard, with a lot of high RPMS, and a lot of high revving fwy miles. So this all makes sense, right? To be burning this much oil? I do know that I am not leaking any though. I use a mix of 15w 50 and 10w30 usually. Is synthetic oil more likely to burn off than dino? Thanks for the help.

BTW, I know have 98,700 miles.... on M104 motor, C280.

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2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)