Saturday my son asked me to show him how to change his oil in his little Toyota Yaris. I figured it was a perfect time while showing him how to do that, I would do little work under the hood on the Mountaineer.
I have been getting some squeaks from the belt or idler pulleys and the PO thought maybe the thermostat was out since the heater didn't heat up as well as it should. On top of that, the Temperature Gauge was not working either.
I plugged in my Wifi OBDII and kicked on FordScan Lite App on my android to see if the temp sensor was getting any voltage...Check!...1V
I pulled the wiring from the Temp Sensor and grounded it to verify the gauge. It checked out good....Check!
(When it goes to ground, the gauge should peg to "Full" or "Hot" status)
I figured it was a bad sensor at this point
and pulled my spares out and shelf'ed them on the battery for later installation to continue my troubleshooting.
I had a new (192 degree) Thermostat and gasket on hand so I figured I would tackle this now, check the pulleys to find the squeak and then swap out sensors.
Thermostat when in like Flynn. The old Thermostat "Looked" fine, it was a Motorcraft unit and could have been Original parts from the factory. Installed the new piece, checked hoses and refilled radiator.
I fired up the "Mounty" to burp the engine and get the air bubbles out...while it was running, my 11 yr old son came out and was curious.
Teachable Moment - I showed him what I was doing, explained sensors, and how the FordScan App interfaces, thermostat functions and belt re-installation. "Cool Dad!" he says.
As the engine was warming up, We jumped into the "Mounty" (to get out of the cold and warm up) and noticed.... HEY! the temp guage was working! I was overjoyed
... but I was still perplexed how changing the thermostat had any bearing on its functionality, except maybe it just routed water towards the sensor to heat it up? Can anyone elaborate how the 2 function together?
It was a good weekend...I think the rear wiper motor crapped out or maybe its the switch, so I will need to troubleshoot it to get it working again.
Ugh! Always something.