Had a new water pump, followed by 3 coolant pipes that needed replacing due to shoddy work.

Replaced the last one this morning, vacuum filled it.

Got up to temp great, all seemed good.

Then fan came on and temp dropped to 1/4. Reb=vving it sounds like a jet taking off due to the fan.

Thermostat housing is hot, one hose out is not.

Any clues, or shall I just follow the bleed process again?

Oh, and I do have cabin heat

And no faults on the IID

Just took it for a drive (hard drive) and it stayed rock sold at middle of gauge.
Expansion tank level had dropped a bit so maybe some air had moved and come out?

From what I understand it takes an age to bleed the air from a 4.4 engine coolant system last time my l322 had a problem it took the mechanic a good while to get the air out of the system. 2017 SDV8 4.4 silicon silver AB
2012 TDV8 4.4 Stornaway Grey AB
2011 TDV8 4.4 Buckingham Blue
2012 VW V6 3.0 Tougreg

Top it up and take it for a run with the tool showing live values of engine and oil temp the gauge itself doesn't really tell you much