Got an 06' 330i, manual tran, 52k miles on it. The water temp light came on and the car went into limp mode. I parked it and noticed that the coolant was a little low so I topped it off with some water. Ran ok the next day for about 10 minutes and then it did it again. I parked it, never saw any obvious puddles of coolant anywhere, but it is again low on coolant. Anyone got any ideas? I would like to fix it on my own if possible. Out of warranty. Thanks.