Part duh...
Couple weeks ago, I noticed some disturbing coolant behavior. Noticed I was a bit low on coolant, added maybe a liter, and by the time I got to work, it pushed it all back out. Did this a couple times, naturally suspecting a head gasket leak pressurizing the system, which I could do without.
It was only ever that last litre that it'd push out so I had hope it was just a rad cap. Anyways , seems like that's what it was.
Compounded by the fact my overflow reservoir lid gasket leaked, so even if it pushed out a tablespoon it made a big mess to scare the crap out of you.
Plus my temp gauge was all over the place. Down almost cold, to popping up a needles width over center and back and forth. Never remotely hot or any white smoke tho.
Anyways, made a new gasket for the res out of squishy silicone, and put a pee bottle on the overflow tube, and I've got maybe a tablespoon out of it, and the coolant res is way over full, so I'm thinking it's fine. Keep hoping it'll suck in that extra coolant when the slug of air finds it's way out, but it's being rather stubborn about it.
Now to get the air out of the damn heater core. Toyota's hose routing doesn't make this easy. Through firewall, UP a couple inches to the top of the heater core, both on supply AND return, creating two air traps.
Added a bleeder at the high point in the engine bay, but I still get a gurgle when the webasto circ pump comes on.
I clearly need to find a steeper place to park it...
Anyways, don't you love $10 parts that can scare you into thinking it's a $1k+ problem. ?