gauge on the dash reads 145-160* while the auto x-ray scanner is showing 207*. Which is right and how do I get the dash gauge to read correctly? Thanx.

 

Your coolant temp sensor could be bad. Try replacing that. Did you change to a lower thermostat, are both fans running, if so your gauge might be right, but I doubt it will run that cool for a long time. Try changing your coolant temp sensor.

 

It's a stock thermostat and I only have the single fan. It comes on with the ignition.

Where does the xray get it's info from? The same sensor, right? Could it be the gauge not interpreting the signal correctly?

 

Nasty TA,

There are at least two temperature sensors on your engine. The sensor for the dash gauge is located on the left cylinder head, between the #1 and #3 spark plugs. It has a single wire connected to it. The CTS that sends temperature data to the ECM is mounted on the front coolant crossover of the intake manifold base. It should have a yellow and a black wire connected to it. One of the two or both could be out of calibration.

The data you are getting from the ECM is derived from the CTS on the intake.

And unless you have changed the fan circuit, the cooling fan should not come on as soon as the ignition is powered up.

 

I've modified the fan circuit to come on with the ignition.

As for the temp sensors, which one should I trust....or replace both of them?