Just picked up an 84 5-speed truck for $200. It sat for a couple of years in a field, but only took a few minutes of work to get it to purr. Noticed late in the day that the temperature guage never came up off cold. Also noticed that the blower would not push out hot air. Ran the engine for 5 minutes atleast, thinking it would be warm enough to kick the guage up and get heat. Does this sound like a bad temp sender or temp guage?

 

sounds like you may be low on coolant, or have a failed or missing thermostat.

 

Coolant is full to the brim. Might go out and swap t-stats with my 94 runner assuming the use the same. Thanks.

 

You could simply take the thermostat out of this truck, and LOOK at it, to see if the valve is tightly closed. If not, I'd just buy a new one from the dealer and drop it in. Not worth your while to open up 2 cooling systems.

You can also test a thermostat by putting it in a pot of water. It shouldn't begin to open until 180F/80C.