93 ranger temp gauge @ cold

Remove the radiator cap and start the motor.

If the fluid moves, the tstat is already open, and the temps will remain low in this case. You need to replace the tstat to correct this. If the fluid does not move, even when the motor should be up to temp (you must carefully remove the cap on a hot motor, or leave the cap off and wait for the engine temp to rise, but you will have difficulty noticing any difference in hot and cold performance in that case), then your water pump is likely to be worn.

Some water pump makers use a plastic impeller (the part that actually moves the coolant), and the impeller blades can wear down. In this case, the water does not circulate well, and the heater remains cold even after the motor should have heated up.

In cold weather, there can be sufficient airflow around the motor to keep it reasonably cool -- if not outright cold -- even if the water pump is not pumping water. Odds are against this, but it could happen. If the tstat remainedj open at all times, the coolant would constantly circulate and never get hot enough for the heater to give you any heat. I think your tstat is toast (stuck open) as my first choice, and the water pump impeller is worn down as my second.

yep, thermostat may fix er right up/ get the 190's dgree one ,lucas

Sounds like your thermostats stuck open....

Better to be stuck open than closed though!! At least you can drive it to get parts!

IYM

Thanks to all for your responses,

I did all of the diagnostics on it myself (with your help) & decided it was the thermostat. It was the original on my truck with 205K miles on it...gotta love my Ranger. Parts were under $10 & had to replace some coolant lost during the interchange but a real cheap repair.

It's working like a charm and the heater is blasting me out now. No more freezing fingers and toes :).

Again, thanks to everyone and have a great holiday season!!!

suzi g

File that one away for future reference ...

Tstat stuck open = cold.

You should see a bit better fuel mileage now as well. A cold motor will be detected by the engine management computer, and it will set the mixture rich (more fuel than air). Rich and Lean refer to the ratio of fuel and air. A cold motor will run rich because in the old days of carburators and chokes, one would set the choke so the cold engine would fire. Setting the choke was equivelent to mechanically holding the air intake closed while the fuel pump continued to add gas. Once the motor fired, the driver would set the choke off, allowing more air into the fuel mixture. You do not have a choke anymore, but the computer accomplishes the same task by adding more gas via setting the injector timing longer. Once the motor heats up, the injector timing is returned to normal, but your engine never reached normal temp so the injector timing remained set long, causing you to use more fuel than you otherwise might have expected.

Now that the motor gets hot, the computer knows and can set the injectors to the normal duty cycle. Two birds with one stone ...