A friend was in town on a long layover, so I picked him up from the airport and took him to get something to eat. We ended up stuck in Honolulu traffic and by the time we got to the restaurant, it was time to get back to the airport. So, we decided to leave and just grab something from a drive-thru on the way back to the airport. The X5 started smoking really badly, so I get out to investigate. The overheating warning light comes on inside the dashboard. I pull into a 7-Eleven and let it cool off. I figure I might as well top off the coolant, so he goes inside and buys a bottle. I pour about a third of the bottle into the vehicle, only to realize it is not filling up. I look underneath the vehicle, and the coolant is pouring out of the bottom. These kind of problems never occur when I am just going to Walmart to waste time. I had to call my friend a cab and he just barely made his flight. I towed my X5 to a local mechanic that specializes in BMWs. It cost about $500 to repair.

After lots of research on this specific model I confirm that the expansion tank in most of these vehicles will go bad at one point or another. This could be caused in multiple ways but the tank itself generally needs to be changed. If you need to get it changed the average price of the tank runs between $65-$100 only for the part. Generally if you will be changing this you will also need to change the hoses. The hoses are approximately $35 a piece and there is 3 that would need to be changed. I had a mechanic quoting me upwards of $85 per hose not including labor. This can be done on your own if you have a general idea of changing parts, if not you have to shell out for the labor. Get the parts on your own.