Temp Gauge Reading/Stays On "0"..?

[snahman]

Hello..First post.!... My temp gauge needle stays on "0" as in ,just lays there even when the engine is hot.. I'm also experiencing engine overheat ( boils out of radiator )when engaging a/c. Some has mentioned fan clutch, thermostat. What do you think may be..? Thanks..!

 

[RonD]

Welcome to TRS

I assume a Ranger 3.0l, what year is it, it matters?

If 2004 or older then temp SENDER on the engine is probably broken.
You can test it by grounding a wire but need to know the year to tell you which wire.

Once you get the temp gauge fixed you can tell if overheating is the fan clutch or a circulation problem by watching the temp gauge while driving.

But if you want to test fan clutch now then after engine sits overnight, so cooled off, start it up and run it for 30seconds-1min, then turn engine off
Open the hood and spin the fan, should spin easily.
Now drive truck for 15minutes+ so radiator is warmed up
Shut off engine and try to spin fan again, it should move but not spin, should be very tight.

 

[snahman]

Welcome to TRS

I assume a Ranger 3.0l, what year is it, it matters?

If 2004 or older then temp SENDER on the engine is probably broken.
You can test it by grounding a wire but need to know the year to tell you which wire.

Once you get the temp gauge fixed you can tell if overheating is the fan clutch or a circulation problem by watching the temp gauge while driving.

But if you want to test fan clutch now then after engine sits overnight, so cooled off, start it up and run it for 30seconds-1min, then turn engine off
Open the hood and spin the fan, should spin easily.
Now drive truck for 15minutes+ so radiator is warmed up
Shut off engine and try to spin fan again, it should move but not spin, should be very tight.

Hello.Thanks for your reply. Doh..I should have listed it. My mistake. It's a '91 Ranger 3.0, 136000'ish miles on her....Thanks again..!

 

[RonD]

1991 will have an ECT sensor, 2 wires, only used by the computer, so not the problem
It will also have a Temp Sender, 1 wire, used only by dash board gauge

These look similar because they do the same thing, read coolant temp, but waste of money to replace the wrong one

If you remove the 1 wire connector and turn on the key the temp gauge should either be above HOT or below COLD
Now use a short wire and Ground that 1 wire to engine or Battery negative.
Gauge should now be Opposite of what it was when wire was disconnected, so full HOT or full COLD
That tests if the wire and gauge are working OK.

 

[snahman]

Another Question..

Hello. As I'm working on this and a Toyota Corolla, I'm trying to find the time for both.....Will a bad thermostat cause the gauge not to work as well as contributing to the running hot problem ?..