"half way" on e 53 is a fake out it's not really a gauge but if it doesn't get to "noon" def not heating up.

Use the hidden menu or some form of live reader to see what the actual temp is.

Do you have cabin heat and what is the ambient temp? You might have a temp sensor fault.

You can use an IR thermometer to measure the upper radiator hose to measure engine temp.

New ≠ fixed. You can do some testing such as block the radiator with cardboard see if it'll warm up: indicates the thermostat stuck open even though new.

A defective temp sensor can cause the non gauge needle on the dash to stay low but if the sensor is at fault you should have a hot hose and cabin heat.

You can clamp a radiator hose to simulate closed thermostat. If the temp climbs fast means you got a defective new tstat.

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)