Rb20 weird overheating

[92r32gts]

Hey guys I got this weird overheating problem & I don't know what it is. I got a 92 r32 gtst with a rb20det under the hood. Car will get to operating temp fine, I'll drive it for about 20-30 min not boosting to hard an my temp gauge with randomly shoot up. First time it happened it got all the way to the "H" I panicked shot off car got out popped hood no leaks, turned ignition to contact fuel pump primed fan came on and realized it was back at half way. My rad is still full of coolant (stock rad), overflow is good, and no weird idle or creamy oil so I doubt its head gasket. Did a oil change / diff flush yesterday. I got stock rad hoses as well.





MODS:
3" FMIC
3" Downpipe
Full turbo back exhaust
K&N intake
Spitfire coils
255 lph fuel pump
Clutch
Oil catch can

Next step is to upgrade rad (mishimoto) & probably grab some samco hoses (upper & lower ), and new thermostat. I also feel as if car doesn't overheat at night time seeing its somewhat cooler but with Ottawas weather its humid beyond belief in the day time. Any suggestion / help would be much appreciated !

[beacher1B0]

The only way to be certain you dont have a bad headgasket is to have a shop gas analyze the vapours coming from your overflow bottle or a cylinder leak down test. Best to be certain and catch it b4 it leaves you stranded.
For now put a new thermostat in it and a coolant change which is pretty easy on a rb20. You could also do a thermo fan mod. Honestly get your headgasket checked out b4 you proceed cause itll b a waste if its leaking.