coolant expansion tank problem! :(

[Suzaku]

For the longest time I have been having strange coolant problems on my 08 yaris, it has always had a coolant smell, and coolant would vanish over time, to NOWHERE, but performance was fine, mileage was excellent, 40-50 mpg, no vanishing oil, till two weeks ago, the level got a bit TOO low ¼ mile from home and the flashing red light of horror flashed on for a few seconds before I made it home, let it cool off, filled it back up, all was fine, replaced the coolant that weekend, good to go.

Started to look into WHY this keeps happening, it seems the pipe to the overflow tank is at direct radiator pressure, and is connected to a rubber hose to the coolant reservoir meaning that there has to be SOME kind of pressure regulation on the overflow tank, or else as the system comes up to pressure, it will blow all the coolant out of the tank, since the cap is about 15psi before it lets loose, it can do that very easily, I suspected the tank was bad or blocked, so I got a HUGE 500ml Large Syringe to try and test the tank, pulled the hose from the filler neck hooked it up and NOTHING, in out, no flow, as I thought, NADA! It's bad,
How often do these tanks go bad?


About to order a Dorman - OE Solutions Engine Coolant Reservoir 603-431

in the mean time, I have to keep filling it cause it spills out all the time cause it cant re-fill from the tank.

Tks!