Today after driving about 20 minutes i noticed that the coolant temp had dropped to the blue line. I pulled over and when I stopped the temp gauge went back to the center position (normal temp), so I started going again. Again after about 5 minutes the temp dropped back to the blue line. I was 5 miles from home so I continued on and when I arrved and stopped it went back to the normal temp. Darn intermittent probelms. I'm thinking it may be a loose wire but am wondering if anyone has seen this before. Any Help would be great.

 

Turn your heat on, if it blows cool you most likely have a stuck open tstat.

 

Sorry for got to mention that I checked the Coolant and was fine and read the OBD and had a p0117 pending.

 

you are saying you don't have a check engine light on but you do have a 117 code, you shouldn't have one without the other normally. The only way you can tell if the sensor needs to be replaced it to use a high end scanner that can read the engines operating temp...

 

P0117 is a code for an open wire to the coolant temp sensor, and if open long enough it can make gauge read low, and temp warning light come on. Note: You can't assume that temp is OK, it might be overheated due to other reasons at this time. Sensor is on top of engine between AC compressor and alternator. Remove connector and clean well, re-install. With the wire open to the sensor, no scanner at any price can get a reading, since the sensor can't talk to the ECU. You plug in scanner may read something like -40F for coolant temp, pretty hard to attain this time of year. You can unplug sensor and see if gauge behaves the same.

 

I am using a Bluetooth enabled reader that works with my Android Tablet. With it I am able to read the ECT and the IAT as well as a bunch of other readings. It allows me to see pending codes and logged codes. It did through a logged code of P1170 for the O2 sensor and a pending p0117 which i'm sure would have become a logged code if I let it happen a third time. When I read the ECT it wasn't abnormally high. I'm most worried about driving it if im missing something.

 

I ment getting a accurate temp on the engine. How ever it should still have the engine light on if the p0117 code is being displayed. Do not assume that its ok to drive.... Get your sensor fixed or you could be causing damage to your engine.

 

OK, I just metered the wires and I get GND on one and 5V on the other. Guess I have to assume the wiring is fine for the time being. Ordering a new sensor. Is there a easy way to replace the sensor, that is without removing the alternator?

 

If the code is "pending" it will not throw the MIL, if left to long it will throw the MIL.
Fix it before the MIL and the pending code will go away without setting off the MIL.

 

Any one have an idea why it would be intermittent? Spike555 do you have anyone that you use locally? that is other than LR. I forgot to thank everyone, So Thanks!