Thermostat Test
WARNING: This page is about a different car, the 2020 Jaguar XE and 2019 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.
Check the electric thermostat for loose or corroded connector(s), check the operation of the electric flow/direction valve(s). If the engine still does not maintain the correct temperature, assume the fault is with the operation of the internal wax type thermostat. Check and replace parts as necessary