Coolant temp 0?

[whitelightning87]

Hey guys, Ive got a problem with my coolant temp guage and Im hoping someone has an answer cause Im lost. I replaced my thermostat a couple months ago and right after I replaced it, my temp gauge would go to 0. The the check engine light came on. Code was p0128, coolant temp sensor. I cleared the code and a couple days later same thing, coolant temp guage would go to 0. We kept doing this for awhile until I replaced my Coolant temp sensor. that time it lasted a few days before it went to 0. I then replaced the pigtail to the sensor. It still now does the same thing. However sometimes the CEL light comes on, sometimes it doesnt. I just ran a full tank of gas, 400 miles with the guage reading 0 and the CEL light never came on. Oh and when the guage goes to 0 the electric fan turns on and you can feel the car lose power. Im at a complete loss as to what it could possibly be. Anyone have any suggestions? Thanks in advance!

[cam98aro]

Re: Coolant temp 0?

i would try to trace the wires from the coolant temp sensor. when the ecu cant get a reading from the sensor it will turn the fans on as a precaution.

if you still have the old sensor i would put it back in.. just incase the new one is damaged/defective

just as a precaution, let the engine warm up and feel both the upper and lower rad hoses to see if they are both warm to verify that the new thermostat is actually working.

are you sure you got the correct thermostat?

[whitelightning87]

Re: Coolant temp 0?

I'll check the hoses today and I'll check them the next time the temp guage reads 0.

Yeah Im sure I got the right thermo, Im ASE P2 cert and a manager at autozone, thats the ONE thing I dont have to worry about lol.

Does anyone know what ohms the signal for the temp sensor should be?

[rhapsodyqueen]

Re: Coolant temp 0?

Sorry to bring this post back from the dead but I didn't want to start a new thread and I'm having the exact same problem!
The only thing different with my car is I haven't changed the thermostat and I don't know if the owner before me changed it. I have had a radiator flush done because the fluid in it was disgusting... but, it was doing this before i had the flush done.
I've only had the car about a month now

[ssms5411]

Re: Coolant temp 0?

Need to bleed all the air out, may take up to several attempts to do it where all the air is out.

[Need4Camaro]

Re: Coolant temp 0?

Hey guys, Ive got a problem with my coolant temp guage and Im hoping someone has an answer cause Im lost. I replaced my thermostat a couple months ago and right after I replaced it, my temp gauge would go to 0. The the check engine light came on. Code was p0128, coolant temp sensor. I cleared the code and a couple days later same thing, coolant temp guage would go to 0. We kept doing this for awhile until I replaced my Coolant temp sensor. that time it lasted a few days before it went to 0. I then replaced the pigtail to the sensor. It still now does the same thing. However sometimes the CEL light comes on, sometimes it doesnt. I just ran a full tank of gas, 400 miles with the guage reading 0 and the CEL light never came on. Oh and when the guage goes to 0 the electric fan turns on and you can feel the car lose power. Im at a complete loss as to what it could possibly be. Anyone have any suggestions? Thanks in advance!

It's not an air bubble... your new thermostat is stuck open. I had this same problem... Here's whats happening, nothing is wrong with your gauge or your fans... this is a fail safe feature thats being triggered because your car is detecting your coolant temperature isn't rising to operating temperature as it normally should, and the PCM goes into failsafe JUST INCASE it's reading from a faulty temperature sensor, so that it won't allow your engine to overheat...
Failsafe Mode:
*Turn OFF temperature sensor* (which is why your gauge goes to 0)
*Turn ON Fans on HI mode*

Replace your thermostat with a Stant from Advanced Auto and it should stop.

and as far as your thermostat failing so soon, don't be surprised...Mine failed within a month of installing it...right after I installed my water pump to be precise, so it can happen... although its usually attributed to other faults such as a corroding radiator, ect...

[cam98aro]

Re: Coolant temp 0?

It's not an air bubble... your new thermostat is stuck open. I had this same problem... Here's whats happening, nothing is wrong with your gauge or your fans... this is a fail safe feature thats being triggered because your car is detecting your coolant temperature isn't rising to operating temperature as it normally should, and the PCM goes into failsafe JUST INCASE it's reading from a faulty temperature sensor, so that it won't allow your engine to overheat...
Failsafe Mode:
*Turn OFF temperature sensor* (which is why your gauge goes to 0)
*Turn ON Fans on HI mode*

Replace your thermostat with a Stant from Advanced Auto and it should stop.

and as far as your thermostat failing so soon, don't be surprised...Mine failed within a month of installing it...right after I installed my water pump to be precise, so it can happen... although its usually attributed to other faults such as a corroding radiator, ect...

is this f body specific? because i have never heard of that, and I have gotten the same code on other gm's before and that never happened.

[Need4Camaro]

Re: Coolant temp 0?

is this f body specific? because i have never heard of that, and I have gotten the same code on other gm's before and that never happened.

Not 100% sure but my car did the EXACT same thing and it was indeed because my thermostat was stuck open. When the temp sits too low for a long period of time the PCM will consider it a faulty reading and disable it (turning your temp reading to 0) so that it wont interfere with coolant operations of the vehicle (as it wont know what to do without the temp gauge)...So it automatically throws the fans on HIGH and runs them all the time because it will no longer know the engine temp just as a failsafe to keep the car cool.

[rhapsodyqueen]

Re: Coolant temp 0?

I wonder if a new thermostat will fix my problem? I've already replaced the temp sensor twice and my temp gauge quits working after driving on the highway. My car throws a ses light and then the temp drops to 0 and the fans turn on. If I clear the ses code the temp gauge will start working again, but not for long.
I've never noticed the engine running below 190-210 when it does work.

[Need4Camaro]

Re: Coolant temp 0?

I wonder if a new thermostat will fix my problem? I've already replaced the temp sensor twice and my temp gauge quits working after driving on the highway. My car throws a ses light and then the temp drops to 0 and the fans turn on. If I clear the ses code the temp gauge will start working again, but not for long.
I've never noticed the engine running below 190-210 when it does work.

Its not that it wont reach operating temperatures... its the fact that it's taking too long for them to rise to operating temperatures... Pop open your thermostat houses and just check to see if its stuck open.