Overheating in stop start traffic only - VZ SV6

[MissSV6]

Ok so I know that there has been a million threads posted on this topic including one from myself awhile ago. BUT the problem is back

When driving around town in stop start traffic without the aircon on the temp gauge is getting up over 1/2 to 3/4 and rising. As soon as you put the aircon on the temp drops back down to 1/2. Motorway driving with or without aircon doesnt affect the temp.

We have had thermostat replaced which was a big job and radiator cap replaced. What could it be? any advise or suggestions please or any recommended reputable mechanics in Brisbane?

[plane driver]

If the temp is going down after you turn on the aircon, it sounds as though the fan may not be working or working properly. Turning on the A/C typically gets the fan(s) on the radiator going almost straight away when the vehicle is moving less than a predetermined speed - about 20 ish. So in slow city stop start conditions the fan is needed. It might be an idea to see if any of the fans are working when the temp goes up and the A/C isn't on. Then turn on the A/C and see which fans are going.

[rabs]

Make sure that the system has no air in it. They are prone to the heater tap leaking out of sharft, water pump leaking, radiator cap falling apart or kicking side ways, and the thermostat leaking. If any of these are leaking and the system gets air in it they will get hot very easily

[db_notso]

if turning aircon on keeps temerature in the NORMAL range
then try swapping the relay with a new one or with another relay

if this doesnt fix it you may still have a leak (if your losing coolant from the resevoir)
OR there may be a fault with the sender

is more likely to be leak or relay though

swap relay with one the same size from inside the engine bay fuse box (one for horn or something like that)
drive it and see if it still overheats

if does still overheat check if fans come on WITHOUT the a/c on if they do its a true overheating problem like leak or not bled properly

if it overheats with swapped relay and fans are on you need a "cooling pressure test" done any joe blog mechanic store can do this
just make sure you tell them what you have replaced, time it was good for before fault reoccured and if its been losing coolant

hope this helps

[MissSV6]

Thanks for your replies I will give everything a go