So, I'm pretty sure I've got a bad thermostat, but would that cause the low coolant light to come on? I've got a 180 thermostat, and the temp keeps climbing past 180 on the highway. So, that leads me to think its a bad thermostat, but the low coolant light is on, but I'm pretty dang full of coolant (almost to the top of radiator and fill neck) This sound right?

 

I'm no cooling expert, but maybe there is sufficient enough coolant in the resivoir, but not in the block itself? Does that make any sense?

The thermostat is so easy to change, you might as well do it. If nothing else, at least check it in a pot of water to see if she opens.

Maybe there is a pocket of air in there, did you try the bleeder screws?

 

well the temp is going to rise above 180 on the highway....why???...dont know just the way GM likes to make it also you could have a bad low coolant sensor...check out http://www.shbox.com for the exact position of the sensor.

 

How far past 180? If this is abnormal, its probably just air or a leak or something...but 180* stats do not operate at 180 degrees. It isn't fully open till 195 degrees, so unless your far from that I wouldn't worry much...

 

bleed the system. sounds like an air pocket.

 

The 180 thermostat will not run at 180 degrees, that is the temperature at which the thermostat opens. A car with a 180 degree thermostat will run at about 210 or the middle mark on the temp gauge.

Unless you are having overheating problems there is no cause for concern.

- Z28WannaB

 

Mine has never run that hot with the 180° thermostat. I run ~12°-15° over the rating of the thermostat, whether it is 160° or 180°.

 

I'm speaking from personal experience, I live in south texas. Most fbodys I see sit around 195-210 with a 180°.

My car runs at about 170° with a 160° thermo and the fans constantly running.

- Z28WannaB