[thane]

i have a 99 2.0 5 speed with 68000 miles
just replaced the t-stat with a factory replacment and had a shop replace the timing belt and water pump.
the only way i can get the blue light of is accelerate as fast as the car will go. wen i get to about 40 to 50 in 3 gear the light will go out and by the time i hit 5 gear the light is back on. any way i dont think it is a big deal it just bugs me.
is this normal or might i have a bad sensor or somthing. i don't have a check engine light. thanks.

 

[jfoj]

Likely you have a bad temperature sending unit. The blue light should go off at about 135F.

An OBDII scan tool that can read and display real time data can also display the engine temp, which should be about 205F at idle after about the first 10 minutes of driving.

Coolant sensor is pretty easy to replace, if it is the black top one, replace it. If it is the green top one, it likely has been replaced, but may need to be replaced again.

 

[Smileybug]

Coolant sensor is pretty easy to replace, if it is the black top one, replace it. If it is the green top one, it likely has been replaced, but may need to be replaced again.

Yup. Coolant temp sensor is my guess.

The "green top" sensor was supposed to be a revised, better sensor, but I got less life out of the green top than the stock one!

 

[Jeff2]

I know the temperature sensor is always the likely suspect, but would a thermostat stuck open cause these symptoms? The Original Poster said it was recently replaced...

 

[billymade]

I would also; check the plug/wiring to the temp sensor, mine had wiring problems. In my case; one of the wires to the connector had broken off! So, any of the wiring, the plug, wiring harness; to the sensor and the senor itself, should be checked.

 

[jfoj]

I know the temperature sensor is always the likely suspect, but would a thermostat stuck open cause these symptoms? The Original Poster said it was recently replaced...

Doubt a stuck open thermostat would be the problem, as the blue light typically goes out around 135F and even with a stuck open thermostat the engine will eventually get up close to operating temperature depending on the length of the drive.

My car with a good thermostat and good temp sensor will turn off the blue light depending on the outside temp between 3/4 mile and 1.5 miles of driving.