Low engine temp on 1992 Ford Ranger

I am having an issue with the water temperature on my 92 Ranger.

Here is the background:

Previously, the temp. gauge would fluctuate drastically, the engine never came up to temp, and there was no heat. Close to the end of our cold season, I replaced the thermostat and heater hoses. Also, ran Prestone radiator flush through the system and back flushed the heater core separately. This seam to fix the fluctuation in the temp. and the lack of heat.

Current status:

Now that it is getting cold again, I am noticing a different problem. The temp. gauge will only get barely above the "C," and there is a small amount of heat coming from the heater. I assume the low heater temp is due to the low engine temp. Is it possible the thermostat has gotten stuck open, or is there some other problem?

Thanks in advance for your help!

1 answer 4 comments
Replace the thermostat and recheck, that's probably it.
I have replaced the thermostate with no change in engine temp. What else could be the cause of a low engine temp?
Make sure the engine temp is actually low, use an infrared temp gun to verify.
Check that you have the appropriate thermostat installed, the temperature range may be wrong.
Is the cooling fan on all the time?
PROBLEM SOLVED!!!! The upper radiator hose temp was around 150F. The coolant temp sensor was malfunctioning, and the heater core was blocked. The two problems combined to make it look like the coolant temps were low. Thanks for the help!
Thanks for the follow up, and glad to hear you have a heater, you're going to need it for the next couple days!
Wednesday 1/06:
Rain 45° F | 32° F
Thursday 1/07:
Chance of Snow 34° F | 16° F
Friday 1/08:
Partly Cloudy 31° F | 14° F