What are the common issues found in the BMW 4 Series cooling system?

I've recently bought a used BMW 4 Series and noticed that the engine temperature tends to fluctuate. What could be causing this issue and how can I resolve it?

The most common issue with the cooling system in the BMW 4 Series is the failure of the water pump. This can lead to overheating of the engine and should be addressed immediately to avoid further damage.

Another possible cause of fluctuating engine temperature could be a faulty thermostat. If the thermostat is stuck open, the engine will take longer to reach optimal operating temperature, while a stuck closed thermostat can lead to overheating.

One more thing to check is the coolant level. Low coolant can result in inadequate cooling and cause engine temperature fluctuations. Make sure to top off the coolant if necessary.