Car overheating while engine is off

[Amf3ar]

Hi,

my vitara (CAMI, 1.6L, 8v, EFI, 1993) after parked with engine off, shows coolant temperature going high...
The temp gauge is at the normal position (hot).
Engine off.
After 10sec if I turn the key, the temp gauge went up over normal.
If I start the engine it goes down (maybe cause the water pump is working...).

- water pump is new
- thermostat is new (82 celsius)
- rad is new

How is that possible? Is there a way to fix it?
I know sidekicks/vitara/trackers have a viscous fan clutch and not an electric one that keeps running when engine is off...but I dont think
an engine overheating while off is normal...

Any tips?

Thanks in advantage!