Broken ECT?

[Arissett]

So a couple months ago I asked about a broken thermostat. My trucks internal temperature wouldn’t move past 145 and the gauge inside the truck wouldn’t really move past the C unless I turnt the AC on. Now with the new thermostat the trucks internal temperature is 160-165 which is still low and the gauge moves a bit more but nothing of note. I would now assume this is a broken ECT sensor right? I don’t have codes though. Also after the truck sits for maybe 5 minutes if I put the key in and turn it to run the gauge inside the car will jump right to the middle and will go back down a bit after it’s been started. Something that really did throw me off is when I was doing this temperature reading today it was sitting at 160 until I revved the engine and it plummeted to 140 and stayed there until I took the truck on a drive where it then sat at 162. If not a broken ECT is there any ideas what this could be? I have a 1999 5.0L V8 Explorer.

 

[C420sailor]

Do you have a scanner capable of live data?

 

[Arissett]

Do you have a scanner capable of live data?

Yes that’s how I’ve gotten my temperature readings.

 

[C420sailor]

Sorry, asked that before I had my caffeine

 

[donalds]

Wait until morning before you start it check all the temp sensors with your scanner they should match outside temp transmission temp ambient etcetera if The temps are different you'll see the bad sensor right away I still think your thermostat is sticking because the temperature is correct if you remove the thermostat that's the temperature you will your engine will run

 

[410Fortune]

I agree it seems the coolant sensor for the computer and the coolant sensor for the dash are both reading the 160-165 degree water temps so your thermostat is likely stuck open

Remember the thermostat controls the minimum temperature the coolant in the engine will run
Your computer wants to see 198-205 before it will switch to open loop

 

[Arissett]

I agree it seems the coolant sensor for the computer and the coolant sensor for the dash are both reading the 160-165 degree water temps so your thermostat is likely stuck open

Remember the thermostat controls the minimum temperature the coolant in the engine will run
Your computer wants to see 198-205 before it will switch to open loop

I agree it seems the coolant sensor for the computer and the coolant sensor for the dash are both reading the 160-165 degree water temps so your thermostat is likely stuck open

Remember the thermostat controls the minimum temperature the coolant in the engine will run
Your computer wants to see 198-205 before it will switch to open loop

Would you know why the temps fluctuate? It’ll hit 165 and then drop and then either sit at 140 or slowly climb to 160 and stay.

 

[410Fortune]

Faulty thermostat or install is best guess