fans coming on after coolant change

[Gokz777]

Had my mechanic change the coolant in my VE SV6 MY9.5 for $250

The old coolant was removed using that special compressor machine so there weren't any air locks and the new coolant was pumped in. Don't have the time to do it myself.

Lately the thermo fans have been kicking in after even short drives (15km). Temp gauge is always around the 1/4 mark. Engineering mode shows the coolant temp being 108 when fans kick in. Gets to 112 then drops and stays around 108. Have not had any warning signs or anything but still not keen on running at that temp for extended periods. Sump temp is 78.
Turning on heater or ac does sweet fa to resolve it. Plus the coolant flowing through the overflow back into the reservoir was boiling just now (could hear it).

Before I take it back and they try and flog me for a water pump or some BS blocked thermostat that's at the back firewall, any idea where they've messed up?
They need to fix it but I can see them trying to pull a short and curly

 

[Benboy]

1. Check the coolant level.

2. Cooling system may have 'air locks'

3. Check you radiator cap - it may not be functioning correctly.

4. Check that none of the hoses have developed soft (weak) spots that could be collapsing and causing problems with coolant flow.

 

[jas98]

had same problem with sisters ve ...was a faulty brand new tridon cap...genuine one fixed it

 

[Gokz777]

1. Check the coolant level.

2. Cooling system may have 'air locks'

3. Check you radiator cap - it may not be functioning correctly.

4. Check that none of the hoses have developed soft (weak) spots that could be collapsing and causing problems with coolant flow.

Thank you Benboy and Jas.
I bought a bottle of the red nulon coolant concentrate and mixed it 50/50. The bloody thing took 6 litres.
Made sure I filled with a cut up bottle and the cap off to avoid air bubbles. The coolant in the chanel was swirling at the end no bubbling.
Checked the hoses and links and all seems normal. No contractions or hot/cold spots.

Still having the same issue. Going to book it in with a specialist. Not willing to take it back to the mechanic after they left that much out. Pissed because never had this problem until the coolant was changed. Never had the fans come, still tripping out over the noise.