Okay, so maybe that title is a bit misleading but blame DriveTribe for that one. However, DriveTribe’s E61 BMW M5 Touring was broken while under Richard Hammond’s watch. See, Hammond was driving it hard, about as hard as it’s probably ever been driven, around a circuit and he then received an engine temperature warning message and had to stop. While the M5’s cooling system worked fine under normal circumstances, it wasn’t capable of handling full-throttle, 8,000-rpm driving for extended periods of time.
Why is this video important or even worth watching? Because it demonstrates how to maintain a high-strung engine such as the E61’s free-breathing 5.0-liter V10. High performance engines are often finicky things and require tight tolerances to function properly. When those tolerances loosen, those engines tend to fail and, in this case, a less-than-perfect cooling system is what did the trick.
When DT took the M5 to the mechanic to get its overheating engine looked at, there was nothing seriously broken. However, the radiator and oil cooler were certainly operating far below their optimum levels. Which meant that anything other than pretty ordinary driving would push them too hard and overheat the engine. That proves that, while your car might seem fine on a normal basis, there can be underlying issues with your engine that aren’t easily noticed.
There were also mild issues with the water pump, as the impeller seemed to have worn down quite a bit, and the thermostat, whose gasket was essentially useless. Combining all of those things meant that the M5’s V10 was struggling to stay cool under hard driving and the entire point of buying an M5 is to drive it hard. So while it might be fine on your commute to work, M5s need to be properly maintained if they’re to operate the way they’re intended to.
So while the E61 M5 Touring did technically break a bit under Richard Hammond’s watch, and it was his hard driving that exposed its failures, it wasn’t actually his fault. The car’s lack of regular maintenance to its cooling system is what actually broke the car. Which means the lesson of the day is to make sure you regularly maintain wear items such as the cooling system if you want your car to operate the way it should without failing.