Video on a water thermostat replacement in a BMW E36. 

E36 Coolant Level Sensor: advanceautoparts.rt8x.net/Lbz9V
E36 Aluminum Thermostat Housing: https://advanceautoparts.rt8x.net/2xGog
E36 Beck Arnley Water Pump: https://amzn.to/32FLIN5

This is a part of a larger coolant system rebuild that I did on my car, and that I do on every BMW E36 I have owned at around 100-120,000 miles. 
The thermostat is quite easy to replace, but because the radiator needs to be removed to get to it, it's best to replace the water pump, and any hoses that are cracked as well.

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