I am trying to think of all possible causes to fix this. Cooling fans working, thermostat working, new water pump, no overheating. Head has been also reworked. Coolant problem aside, now the car wont even start, while cranking is backfiring into exhaust, so i think timing belt has also jumped one tooth.
Coolant problem accurs only with hight boost ( 1.5 - 1.9bar ) and only when the boost duration is longer. 1 gear wot everything ok, usually happens with 2 gear. Funny thing is on Friday i made logs with 3rd gear and everything was ok and on Sa accelerated 1st to red and 2nd to redline and popped .
Will start to diagnose on Monday. Will check for blockage in coolant system. Thanks for advice
Forgot to add that, sometimes under hight boost there is this high pitch sound like tires squeking and when i think about that it reminds me air passing thin metal. So i guess headgasket is also possibility. Might need to buy arp bolts.