Thermostat

[upallnight]

Originally Posted by SlickGT1

On our 4.8is, the tstat has a sensor. That sensor technically measures when the tstat fails. I know this because I had it happen. It was a ridiculously simple job on the 4.8.

That being said. Does your car take a really long time to warm up in the morning. That is also an indication of a failed Tstat.

I also question how these mechanics know you have a failed tstat. If there is no code for it, how did they come to this conclusion?

This what the OP stated

The shop is saying that my thermostat need replacing, this from their computer, no indication on the dash

A failed thermostat will not set off a check engine or service engine soon light, but it will be logged into the DME as a problem, which can be retrieved if you have the proper software connected to the car.