Coolant Temp Sensor and Cooling Fan

J

jrtmouse

New member
Joined
Dec 5, 2013
Messages
6
Reaction score
0
Points
0
I have a 2000 Sunfire (2.2L). There was nothing wrong with this car until I decided to drive it after it had been sitting for a month in the hot weather. It overheated.

I added water that day to the reservoir (as there was no radiator inlet that I could see) and it has continued to overheat since.

I noticed that the cooling fan would not run at all, even with a/c and while temp near the red. I checked the cooling fan, fuse (30) and cooling fan relay and confirmed they were working. To do so, I eventually unplugged the coolant temp sensor. Once I unplugged that the cooling fan would turn on. I felt good that it wasn't necessarily the cooling fan but the coolant temp sensor.

I replaced the old coolant temp sensor just last night with this part from AutoZone:
Duralast/Coolant Temperature Sensor (SU102), complete with splicing of new pigtail

I started the car, let it run for about 5 minutes, and noticed the middle of the sensor had completely MELTED leaving the metal portion screwed into the socket and the harness connected to the pigtail. Everything else was gone with the two elements exposed to the world.

What went wrong? Faulty part?
 
Last edited:
Only other possibility is the head is full of air or exhaust gas, not coolant, which melted the sensor.
 
Does this mean I have a blown head gasket?
Why would there be air in the head?
How would one get rid of the air from the head?
 
Last edited:
Unless the coolant reservoir overflowed the day of the original problem your having to add coolant to it means you have an external or internal leak. That same leak can lead to air in the system. Pressure test the cooling system and try to have a hydrocarbon test done on the coolant.
______________________________
 
DIY FAIL! Update...

I pride myself in being quite competent in most things I set out to do. Thanks to forums like these and YouTube, I’ve been able to successfully accomplish a lot. I’ve remodeled kitchens, repaired appliances, and troublehot (sp?) many an issue. I’ve successfully replaced sensors and just recently a thermostat on one of my other vehicles. However, I’m embarrassed to report that this last replacement of this particular sensor was unsuccessful and here’s why…

For whatever reason, I replaced what I believe to be the oxygen sensor with the coolant temp sensor. Hence the reason that thing melted! So now I have quite the problem. I’ve found where the coolant temp sensor SHOULD go when I decide to go through the effort of replacing it. Meanwhile, I have an oxygen sensor with the wires snipped at the end and a car missing a harness as I snipped it to splice the coolant sensor.

I'm going to see if I can somehow salvage the old oxygen sensor and somehow splice what's left of the wires to those of the car.

Quite the cluster! Stay tuned…
 
wow quiet a mess, sorry to hear that but at least we all know now what went wrong.
 
Update

I've replaced the coolant temp sensor (and the innocent O2 sensor. :-/). I drained the old coolant replacing it with new. Took the car for a spin and the coolant I had just added was then a dirty brown and flowing from the reservoir via the black tube onto the ground.

I then replaced the thermostat, added more coolant, took the car for a spin and it started overheating real fast this time. This time I believe the coolant was not leaking from the reservoir but from another source. I have yet to locate the source.

That's my status. I've yet to see the cooling fan come on. I guess my next step outside of the leaking coolant issue is to replace the cooling fan...
 
i thought you already confirmed that the fan itself works? Did you bleed the air out of the system when you drained the system?
______________________________
 
You must log in or register to reply here.

Share this page

Back
Top