Hello all,

Just inherited a 1991 Ford Ranger Manual 5 speed from my Father in law. He finally leveled up to a newer truck. He told me in the past he had changed out the Temperature Sensor (Part that controls coolant flow, to my understanding) and that that part was good. However, the gauge on the dash has never worked. He said it was likely the Sender.

I found an old forum on here instructing to unplug the One wire attached to the Sender, ground it with the key to the truck on, and verify if the gauge on the dash jumps all the way to Hot. After performing that test and verifying that it did indeed do this, I assumed it was a Bad Sender. I purchased and installed a new one this weekend. In doing so I lost a lot of coolant, but I replaced it after the install. After all this, the gauge will only creep up to right above C after driving around for 15 min. That's more than it has ever responded in the past, but I guess I was under the assumption that after it was swapped out, the needle would point straight up - halfway from C and H.

Did I install it incorrectly? I did have to really crank on the Sender to screw in all the threads on the new part. I read somewhere that maybe I didn't have to do that and that some threads should have been exposed?
I was also worried about an air lock. My heat works after the engine warms up though. I also ran the engine with the radiator cap off, adding coolant until it was topped off, periodically giving it some gas here and there during this process.

So do I just have a bad part? Installed wrong? The One wire grounding test makes me believe the wiring and the dash gauge are OK. Curious on what more experienced owners thoughts are; I will say I'm a woodworker - not a mechanic, so I'm out of my element when working on engines.

Thanks!

 

Welcome to the forum

Yes, the test you did shows the wire and gauge are working as they should

Yes, it reads like new sender is installed correctly

You have a 2.3l engine, you should include that with questions

These engines run cooler and the Temp sender is at the rear of the engine not at the top front where coolant will be the warmest
The thermostat is what sets minimum operating temp, its at the engine end of upper radiator hose in its own housing
Previous owner may have installed a 160deg or 180deg model, it needs a 195deg model
But temp gauge would still be only up to about 1/3 on this engine

The V6 Rangers run just below 1/2, Ford Temp gauge has 210deg as 1/2, operating temp is 195degF

If your heater is blowing hot then all is well, all the air is out

 

Thanks for the reply RonD. Makes me feel better knowing all that you said. Yes, I should have specified the 2.3L Engine bit. I think I'll keep truckin on like normal then! I did notice it got up to almost the "N" on "Normal" after driving home then letting it sit for a few minutes. I guess all cars are different and my previous vehicle showed the needle as dead in between H and C when it was warmed up.

Also, this website is super handy. Looking forward to utilizing it in the future as maintenance issues that are out of my realm arise.

Best,