help!! temp needle stays all the way down and no heat Options

[celicaluva79]

My heater used to work great. Now it blows but its not hot. I notice my temperature gauge never hardly goes up, most of time stays below the bottom. Coukd this be my thermostat? Also just had my engine rebuilt...could it be something that he forgot to hook back up?

[Galcobar]

That would be rather difficult, since the thermostat is about two inches long and the bulge in the water inlet which holds it is only half that high. And on a 7AFE particularly the thermostat would have to be installed at an odd angle which should prevent the neck from sealing to the block.

Easier explanation is that the mechanic who rebuilt the engine forgot to install a new thermostat (should also be installed with a new gasket), or else the thermostat has failed in the open position.

However, I find myself wondering if that's not the only issue. I had a thermostat get stuck open, and it was noticeable from the way the temperature gauge would dip with speed. The engine would still get up to normal operating temperature while the car idled. Is the cooling fan on the radiator running all the time? If it is, the mechanic probably forgot to plug in the fan temperature sensor switch or the sensor switch is faulty.