2013 1.6 volvo v40 d2 rdesign. Coolant problem
 

My car was over heating so i had my tstat replaced and wil in the garage had water pump and belt done.
The car doesnt seem to over heat now but seems to be a problem with the coolant getting round.
The radiator doesnt get warm and i sometimes loose thr heat from the heaters.
The problem seems to be intermittent as i drove it 200 mile with no issues and since then i have had it bled up in garden ticking over fine.
Any ideas?
O and also had a new rad too

How many miles has the engine done? Why did the radiator need replacing?

Engine done 105000. And changed rad to rule out blocked rad causing the prob.

Does the fan cut out? Or is it on all the time?

No the fan isnt on all the time