BMW E39 M5 Coolant Expansion Tank Replacement DIY (1998-2003 BMW M5, S62 Engine)

Another part of the cooling system made from plastic, the expansion tanks is a relatively common source of coolant leaks for an E39 M5. As such, replacing the tank is a nearly universal experience for owners, so check yours if it's been a while. The clear plastic makes it easy to see the coolant level, but that also makes it prone to cracking from heat-related degradation. A general replacement interval is within five years of regular use, though they can crack before then.

In this video, Mike Hidalgo, FCP Euro's Professional DIYer, replaces the coolant expansion tank on a BMW E39 M5.