The E39 followed the pattern of weak cooling systems set by BMW in the late 80's. But it seems these models are excessively prone to overheating, causing huge repair bills. Due to a low coolant capacity once these engines enter the "Red Zone" on the gauge, thousands of dollars in damage is already happening.
Once these models have more than 80,000 miles they should be serviced, then every 80,000 miles there after. Water pumps begin to fail, thermostats housings crack, along with expansion tanks and begin to leak due to plastic construction.
Eliminate one of the weak links in your cooling system with the included aluminum thermostat housing. By installing this aluminum unit, you have no further worries of plastic housing failure.
This kit was put together by ECS including the basic parts that need replaced.
