While warming up my car for ten minutes, i came out to find the interior cold. The water temp was up in the high end of the band, and i smelled coolant. Shut the engine off. Pried the icy hood open, and found coolant everywhere. The uper radiator hose was sucked closed as well.

Am I right in suspecting a thermostat?

The thermo is a factory thermo, about 4 months old. I'm on call for work right now without a car, so any thoughts will be GREATLY appreciated.

 

I would replace your thermostat with a factory one not a generic one. Also bleed the system well.
Thanks Robert

 

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How fresh is your antifreeze and what ratio are you running?
Feel your lower rad hose, see if maybe it's frozen.

 

Wouldn't it expand then? But definitely check for air in the system..

 

update:

I've filled and bled the system. I've got heat again. I can't find where the coolant vented from earlier this morning though. is there a pressure release valve somewhere????

My mixture ratio was to blame. I was running way too much h20 in the system.

 

^ the pressure release valve is built into the radiator cap. It releases at .9 bar (13psi). That's how modern (60s and later) sealed cooling systems work.

But if you have a split hose or something the pressurized coolant is going to shoot out of there.

 

the system is holding tight now, with no visible leaks anywhere. problem apparently solved for now somehow...which is great because now my brakes are out. 9 degree temps are hell on an old car.

 

It normally shouldnt build pressure to the point where the cap have to release the pressure. Also, when the cap vents it releases into the coolant reservoir.
and wow at 9 degrees lol.

 

Oh pshaw.
Yesterday when I went out to start my car it was -15°...she fired right up.
In fact, it was more functional than I in those temps.

Started down the road and had a horrible vibration in the rear, pulled over and discovered the passenger wheel had a big chuck of ice on part of the rim...in essence, a two pound misplaced wheel weight.

Sometimes driving in the ice and snow ain't so bad...I realized that even a miserly old fart like me can drift without worrying about trashing the tires...

 

^^^
haha
the coldest I ever started the rx7 in Philadelphia is -10 at 6am driving to work at the shipyard.....I was suprised at how good it ran.

 

I started up my N/A 2 years ago at -35 Celcius.
There was at least a 1/2 to 1 inch of Pure ICE On the car.After the car started and was heated up inside I picked up a whole Windshield of ICE...( the craziest thing I ever seen..an ICE windshield!)

 

There needs to be at least 30% antifreeze to keep it from freezing at your temperature. Even close to that percentage or temperature and the coolant will get thick like gel and have trouble circulating. Either freezing or thickening could have caused lack of circulation which makes heat and pressure build up in one area, yet leave your heater cold.

If nothing's leaking the coolant probably came out of the cap on the fill neck, which releases any pressure above its rated pressure (13 psi? I forget).