Why is my coolant leaking and oil leaking and my check fluid level coming on? on 2003 BMW X5

I have replaced the expansion tank but the new one is leaking also

Asked by for the 2003 BMW X5
1 answer
I removed my expansion tank and am installing a new backing plate that it mounts to. Im wondering if they put lube on the o rings.Its probably not the new tank thats leaking.