heat isn't working
 

What should I be looking for if my heat suddenly stopped working? I have a 160degree thermostat but that's been in there for 2 years and the heat as worked fine in the past. Could it be stuck open or is there another possible problem? My car has always ran extremly cool, barely going above the 160degree mark on the gauge.

Thanks for the help.

Sounds like a stat to me. I have had them stick open. If you dont have the PCM tuned for a 160 you may want to run a 180 in the winter anyway. But if the PCM is tuned for the 160 the fans will stay on and I think the timing or fuel curve may make it ping with the hotter stat. First start by checking the coolant level though. If there are air pockets in the system heat can be lost

Is it blowing cold air, or not blowing air at all?

The vacuum operated diverter flaps inside the air box
have to steer airflow through the heater core. If these
are stuck or you lost vacuum then maybe no heat,
depending on where it got stuck. Might tear into the
climate control, check the backside of the control and
see if there's vacuum in (engine running) etc. If you
switch the mode knob and listen carefully you should
hear little hisses and clunks under the dash as it moves
the flaps around.

have you used any stop leak in your radiator?

i dont see what a vaccume leak has to do with the water temprature not exceeding 160 degrees on the water temprature gage on your dash board but you can always check your diverters as jimmyblue said. I was always under the impression that if a deverter did fail, it would fail in the "heat" position and not the "cold" position, but I have no littatrure to support this just hearsay