Ok, I have been through the bhg on one of my supras. Now my wifes is filling the overflow. Has never overheated, no gurgle, passed the block test. I changed the rad cap, checked thermo, was stuck shut, replaced that, oil looks clean, exhaust seems normal. No power loss. After I replaced the thermo drove about 8 miles check overflow was not full. Checked after cool down still not full. Drove again now its full. My next check is a compression check. Is there anything else I am missing?