o and by the way, i put a k&n intakeo n my car. it makes the turbo sound much more high pitched, and the boost release is a lot louder too.

its common for supras blown headgaskets to slowly only under boost and those gasses push out or lets say they create higher pressure and consequently the rad. cap releases pressure. during that time ,the first thing comming out is the coolant not the gas since the gas is pushing the coolant.... and usually it only happens under boost or while driving, so dont let the car idle and hope to see the coolant overflow to get filled.....

i know, ive realized ive been making my car boost a lot mor, and its getting filled up faster now.

OOPS....i HOPE YOU HAVE MONEY SAVED FOR THE REPAIR...EVEN IF YOU DOIT YOUR SELF AND MACHINE THE HEAD IT'LL COST YOU AT LEAST 500 BUCKAROOS..... GOOD LUCK DUDE...

i dk if it is the head gasket for sure

easy killer.
no white smoke. burns a little oil thru the turbo. no milky oil. i dk.

On a properly sealed cooling system coolant gets forced into the overflow when heated and subsequently gets drawn back into the block through the overflow and radiator. Now if your overflow is filling up after you drive but after it cools its not going back to the level it was when it was cold, that means you have a leak in your cooling system and its drawing air instead of coolant when it cools. The leak could be in the radiator, heater core, water pump, any one of the numerous rubber coolant hoses, or it could be the head gasket. Im a huge fan of pressure testing the coolant system so I would recommend you start there if you are concerned about your cooling system.

Just to confirm, there is no PCV valve on turbo MK3 supras.