Since we are the topic of BMW engines, let’s look at saving the M52TU, M54 and M56 aluminum 6 cylinders.
The problem is the customer cooks the motor. You know when they say, “I pulled over as soon as I saw light”. Right, 10 miles later. Or you get that “it only overheated a little”.
So the thermostat for an example fails, thus causing a serious overheating condition, and “pops” the head gasket or worse, cracks the cylinder head.