'95 Thermostat question

[12beemer34]

'95 Explorer Eddie Bauer, V6 pushrod (250,000km / 155,000m)


My temp gauge consistently reads on the cold end of the scale. I put in a failsafe thermostat two years ago, then changed it just a few weeks ago after thinking it had failed open (it didn't fail after all). Turns out the new one works just the same (I put in a "winter" thermostat). I get lots of heat in the cab (50c/122F) at the dash vents. I've temped the hose (cast iron) that comes off the top of the thermostat housing at 77c/170F after my drive to work and engine at idle (ambient air temp is -8c/17F). But the gauge never reads above the 1/3 mark. As I drive (or let it idle) it will move between the low end of the arc and 1/3 (never reaching the half way point). Sometimes if it's very cold it'll dip back below the arch and almost touch the "C". I can tell that the thermostat is opening and closing because the temp gauge will slowly rise/fall as I drive.

I believe my thermostat is operating properly and that I have a gauge and/or sending unit problem.

Questions (if anybody knows):
- what is the ohm reading for the temp sending unit at 100c/212F (or any temp range). I'd like to see if my unit is bad and figure I can check it by placing it in boiling water.
- what's the resistance range for the temp gauge to go from the cool to hot range (staying within the normal operating temp range).
- what's a normal temp to read at the thermostat housing once warmed up (if anybody has done that)
- does the sending unit only signal the gauge, or the gauge AND engine computer? (worried about poor mileage)

Thanks,
Sasha

 

[gtyates]

I can't answer your spesific questions, but I can say my '96 is the same way. Recently the thermostat failed open, with little heat in the cab and the gauge never moved off of cold. Since replacing I get HOT heat in the cab but the gauge never gets above about 1/3. My Dad owned the truck before me and said it has always been this way. He even had the sending unit replaced early on under warranty and it did not change the 1/3 reading after fully warmed up. I can say for sure though that the sendig unit for the gauge is separate from the one for the computer.

 

[Runnin'OnEmpty]

I think you're OK with the temp readings. All my vehicles
read low temps in the winter, but they run fine.
It's because everything's cold; the sender, wires, gauge,
and that changes the electrical resistance and gauge
readings.....

 

[96eb96]

'95 Explorer Eddie Bauer, V6 pushrod (250,000km / 155,000m)


My temp gauge consistently reads on the cold end of the scale. I put in a failsafe thermostat two years ago, then changed it just a few weeks ago after thinking it had failed open (it didn't fail after all). Turns out the new one works just the same (I put in a "winter" thermostat). I get lots of heat in the cab (50c/122F) at the dash vents. I've temped the hose (cast iron) that comes off the top of the thermostat housing at 77c/170F after my drive to work and engine at idle (ambient air temp is -8c/17F). But the gauge never reads above the 1/3 mark. As I drive (or let it idle) it will move between the low end of the arc and 1/3 (never reaching the half way point). Sometimes if it's very cold it'll dip back below the arch and almost touch the "C". I can tell that the thermostat is opening and closing because the temp gauge will slowly rise/fall as I drive.

I believe my thermostat is operating properly and that I have a gauge and/or sending unit problem.

Questions (if anybody knows):
- what is the ohm reading for the temp sending unit at 100c/212F (or any temp range). I'd like to see if my unit is bad and figure I can check it by placing it in boiling water.
- what's the resistance range for the temp gauge to go from the cool to hot range (staying within the normal operating temp range).
- what's a normal temp to read at the thermostat housing once warmed up (if anybody has done that)
- does the sending unit only signal the gauge, or the gauge AND engine computer? (worried about poor mileage)

Thanks,
Sasha

The gauge and computer have separate sensors. The dash unit has a one wire sensor.

I can tell you that the sending unit to the gauge goes bad and does what you describe, but people have chased this problem with waterpumps, thermostats, flushes etc. Its probably a good idea to replace that one wire sensor first, I had a very similar problem and it was that. The unit cost me under $5.

I have a new waterpump, radiator, sender and thermostat on my 96, and it will vary sometimes between 1/4 cold and normal especially if its very cold out. Turning the heat on will cause it to drop and then it recovers. I wonder if the fan clutch is working "too well" and providing too much cooling when it should not be spinning.

 

[12beemer34]

Thanks everyone for the quick replies. This site/forum ROCKS! So informative and helpful.

I'll just live with the low readings for now. I may pick up a new sending unit if it gets on my nerves any more.

Thanks again all.

Sasha