Coolant Temp

[MarkWilliams64]

2005 Impala 3.4L 117K miles.
What would make the Coolant Temp all of a sudden register about 170 Deg. on starting the Engine after it has set out all night in 20 Deg. Temps.

There is no way the temp could be that high on starting the car.

While driving the temp rises to 215 and fluctuates between 210 and 215.
This is higher than normal.

It doesn't appear to be overheating.

Thinking about changing out the Thermostat and the Coolant Temperature sensor.

Any ideas.

[rhandwor]

Originally Posted by MarkWilliams64

2005 Impala 3.4L 117K miles.
What would make the Coolant Temp all of a sudden register about 170 Deg. on starting the Engine after it has set out all night in 20 Deg. Temps.

There is no way the temp could be that high on starting the car.

While driving the temp rises to 215 and fluctuates between 210 and 215.
This is higher than normal.

It doesn't appear to be overheating.

Thinking about changing out the Thermostat and the Coolant Temperature sensor.

Any ideas.

Disconnect the wire going to the sensor ground the wire the needle should peg.
If this is the case I would try a new coolant sensor.

[Tech II]

I believe there is only one sensor for this car(older versions had a single wire sensor for the gauges, and a 2 wire for the ECM).....

So as rhandwor states, just disconnect the sensor harness from the sensor....turn key to on(don't start).....this will make the sensor reading go to -30F on a scan tool, or peg low on the gauge.....

[MarkWilliams64]

Does anyone have instructions on replacing this Temp Sensor, picked one up at NAPA and going to try and do it today.

[rhandwor]

Originally Posted by MarkWilliams64

Does anyone have instructions on replacing this Temp Sensor, picked one up at NAPA and going to try and do it today.

With the engine off let it cool and then drain enough coolant to use a deep socket and ratchet and remove the sensor. The new sensor should have thread sealant on the threads.

[MarkWilliams64]

Replaced the Sensor with one from Napa, problem went away and then came back worse in 2 days. Going to have someone scan it today to check both the new sensor and the Instrument Panel Cluster. This guy said that I might have got a bad new sensor and he recommends a Delco part instead. He also stated that the 04-05 vintage of these cars had some issues with the Stepper Motors going bad in the IPC. The gage does not go back to zero when turned off, it is stuck at like 170-200 range and temp just goes up from there.

Anybody have any thoughts on this?

[57chevyragtop]

I have had trouble in the past year with NAPA temp sensor. You are much better of with GM sensor part from dealer. the connecting wire connector (wire side) can be bad as well so you may need to splice in new connector. I believe GM Part comes with new connector.

[MarkWilliams64]

Had a Chevy Dealer Mechanic scan it with Tech II, the temp sensor is okay, but the IP cluster has to be replaced. The stepper motor for the temperature gauge is shot. Dorman remans them and puts upgraded motors in them to fix the problem. Plus the unit comes with all new bulbs. So this is on my list to do. Found a video on You Tube how to replace it. Does not seem to terrible.