BMW 01 Expansion Tank anti freeze empty in two days
There has to be. Look for a wet spot or white reside to indicate dried coolant. The expansion tank will leak from the smallest crack that you can't even see, only under pressure. If it is the original, replace it now with the hoses, thermostat and water pump. www.fcpeuro.com and purchase the coolant system refresh kit.
Maybe a failed head gasket? How does the oil look?
There may be an air pocket in the system. If you have recently flushed and/or done any work with your coolant, it can cause this (mine did it just 2 days ago!). Turn the car on, fill the coolant reservoir with the cap off (MAKE SURE IT IS NOT HOT!!!), and let it cycle. As it warms up, squeeze the large hose on top to "burp" the system. I hope this helps - Good Luck!!
Looking for a Used 5 Series in your area?
CarGurus has 14,897 nationwide 5 Series listings starting at $1,000.
Search BMW 5 Series Questions
BMW 5 Series Experts