I was told to run it a bit and then remove rad cap as their might be an airlock as coolant just got changed in the service before looking deeper issues could this be a possibility ?
You could massage the hoses if you suspect airlocks.
Been quite a while since I've had a vehicle with that issue but Subaru EJ22 motor comes to mind and had side tanks. On that if there was an airlock it boiled, I massaged the hoses on that to sort it, was a PITA. Similar situation, no overheat issue, leaky waterpump, get it replaced , all of a sudden overheat, told dud thermostat, I said nup, he cuts it apart to make it bypass.
Real issue was airlock.
You could run it until it's warm enough for the thermostat to open and have the coolant circulating. Check the temp of the hoses upper and lower. If ones cold or cool and the other boiling hot that would suggest a potential airlock or faulty thermostat.
Personally if it was 100% good and some work had been performed and now issues, I would be suspicious.
Are we talking litres of coolant being replaced and frequency?
Some of the instructions the manual gives.
" Tighten the radiator drain plug securely.
4. Remove the coolant reservoir tank. Drain the coolant and reinstall the coolant reservoir tank. Fill the coolant reservoir tank to the "F" mark with coolant mixture.(coolant 5 : water 5)
5. Fill coolant mixture into the radiator to the base of filler neck. Gently squeeze the upper/lower hoses of radiator so as to bleed air easily."
