very WEIRD overheating problem

[j00ni3]

i was driving my friends s14 zenki bone stock ... absolutely no mods...

auto ...

now i was driving down i80 and it was fine... got on the 95 pulled out on pal park. i got onto broad ave and was at a red light...

no exhaust upgrades so i couldn't hear it ... but then i felt the car trying to nudge forward... so i looked at the tac and it was going a little bit over 1000 rpm .. which was weird with no a/c or anything on... and i looked right over to the temp and it was over heating like crazy~~ ...

so we stopped it and let it cool ... turned it back on and then drove.... it was fine for like 5 min then again... so my friend says to me ... it's ok ... just rev it a bit... so i slap her into neutral and i rev it around 4000-5000 ... ( i don't know if that was good but hey not my car ) and the temp gauge started to go down ... so i was like.. hum... ok maybe system is not bleeded... but after that it ran FINE... for like 4 hours ... in local traffic/ and highway

then we went to his house... i flushed the system twice over.... put in water wetter and distilled water... no anti ...

i bled it on his driveway... ( steep ) with theheat on and everything ... so only coolant was coming out of the bleeder hole... no air

we drove... for about 20 min and then let it cool ... and put it ontop of his new cement driveway to see for any leaks...

nothing...

so he drove.... and about 10 min later... B"OOM starts to overheat like a mofo..

so he s tarts revving which i wasn't really fond of... and then it cools down...

now we drove her back and checked for any leaks on a jack and everything ... nothing... checked for oil in the coolant ... NOTHing ...

when we start the car with the rad cap off... it doesn't like GOOSH out... it just like.. ripples a bit.. but that's it ...

edit :: also ... checked his compression at my house... IT Was ALL FINE... no abnormal compression in any cylinders...

edit :: my friend took out the clutch of the fan and checked it like the fsm states.. no problem ... fans kick in at right temps... everything's fine~~~ AHHHHHHHHHH driving me crazy

what can it be? help