Well I'm revisiting my over heating problem. I lost a few runs at the Brooksvill auto cross due to the heat climbing...

I have an 02 Wrx, 5spd, wagon, 2.0L, turbo....white...

My original problem, a few months ago, was a stuck thermostat. I removed the stuck thermostat and put a new one in but it did not fix the problem. I put the new thermostat in a pot of boiling water and it did not open until 200 degrees. So right now i am running no thermostat.

My problem right now appears to be under very aggressive driving for a long time the heat will climb and move all of the fluid in the system into the overflow tank until it spills all over the road. Under normal driving the heat will rise and then fall very quickly. After bleeding the system the erratic rise and fall goes away for about a week.
-Brand new upper/lower hoses
-No thermostat
-Radiator holds 16 psi on a radiator pressure tester.
-Pulled 185 awhp on a stock tune
-Tuned to have about 215 awhp right now @ 15.5 psi
-The heater works on and off
-i can blow water through the motor and radiator with out any blockages

I doubt it is a head gasket or warped head because of the pull and numbers the motor puts out. Along with the holding 16psi in the radiator with a pressure tester i doubt there is a significant leak, bad radiator cap, or bad head gasket.

I am so confused. Maybe one of the ancillary hoses, maybe a cap, maybe a clogged passage somewhere, bad water pump, or maybe worst of all a bad head gasket.

Is there any way to test a water pump? Defiantly getting fed up with the heat climbing, so i am just thinking about installing a large radiator and an electric in line water pump...

Thanks for reading or even skimming