Ls1 running hot fans turning on immediately

[pieman18]

hey all

So I’ve recently bought a vy clubby that up until this point has been running well

It’s started running really hot. Needle rises to the 3rd qtr mark on the temp gauge and the fans kick in basically when you turn the car on and keep running after the car is switched off.
I replaced the thermostat and topped up the coolant with the factory specs, it made no difference.
Engine still runs way above the normal temps it’s should operate at.
I’ve just replaced the exhaust system in it, as well as spark plugs, leads and 02 sensors, but have touched nothing to do with the cooling system or anything close to it

I just wanna drive my new car without the worry of popping the cooling system somewhere on the highway

Any ideas what it could be?

Edit....when I turn the car off the fans stay on for a minute or so, but the temp gauge goes right back to full cold, then when I turn it back on again, it doesn’t go back to the high temp straight away, it rises as slowly as it does when you start the car from cold
I’m very confused

Thanks guys
Dan...