[locopwr]

I have a 2001 Impala 3.8, driving on the highway couple weeks ago very cold night, noticed temp gage (dial) was just about 150. Later that same evening returning home, gage went completely south, MIL came on and now the fans run on high when engine shuts down. Left fan motor is making noise (maybe bad brushes). Pull the codes > P0114 & P0117. Replaced the ETC & theromstat - No change. Scanner reading ETC @ 284 with sensor plugged in and 38 unplugged. Reading steady 5v ref with engine running. Not sure whats causing what problem...any suggestions out there....

 

[g25racer]

Id be willing to bet its the coolant temp sensor. Also had this issue with mine. A failing coolant temp sensor give the pcm false readings therefor throws your car into a "failsafe" which, throws the fans on full blast all the time and for 90sec or so after key is off. Dexcool overtime creates a nasty residue inside the cooling system therefor plugs thermostat and coats the temp sensor. Such a common problem. Overtime your temp gauge will stop moving at all. I would also recommend a coolant flush. Get this problem fixed ASAP or your fan bearings WILL fail and that's not a fun repair or a cheap one at that.

 

[kingnutin]

I assumed that's what he meant by "ETC". Have you cleared the codes? Sometimes the computer doesn't recognize the change right away.

 

[g25racer]

What is "etc"? You guys mean ECT (electronic coolant temp). Either way it's technically called a CTS (coolant temp sensor).