It has the 360ci engine.

I've changed the Tstat twice.

Flushed the system.

removed cooling fan

I even went as far as to put cardboard in front of the radiator.

The engine runs at a constant 124 Degrees F! Any Ideas? I am stumped! I've checked it with a infrared thermometer and a contact thermometer.

 

what is the temp on the t-stat you are using? it should be a 195 from the factory, or a 180 for a slightly cooler water temp

 

Where are you reading temps with the infared. The best place is on the side of the cylinder head towards the back if possible. The thermostat is the sole part that determines engine temp and the chances of 3 bad t-stats is highly unlikely. Unless you have alot of coolant bypassing the t-stat housing(which I dont see possible) your temps should come up close to what the t-stat rated for. I bet you may just have a bad temp sending unit and were taking reading from a bad spot.

 

The temp sensing unit is on the intake manifold.. towards the front passenger side if i remember right.. its just a small brass plug with a wire connector coming out of it.. Its also pretty brittle don't use care when installing/ uninstalling it..

 

I'm with a57chevy43.
You need to check the coolant temp with something like the Auto Enginuity scan tool.

 

Actually it can flow around the T-stat.


What happens is the neck is metal and the intake manifold is aluminum. Some rust can form and pit the T-stat neck. After a while some coolant can and will flow around the T-stat. This in return pits the intake manifold sealing surface to the T-stat. Once you remove the T-stat you clean up the surface to the intake and before you place the new tested T-stat in you place a little RTV spread out and lay the T-stat on top, next you go down to the dealer and for like $10 bucks get a replacement neck. Get yourself a thick gasket and a little more RTV and problem fixed.

Take a temperature at the T-stat and ensure the coolant is up to the correct temperature so that it is operating correctly.

Next you could have a bad sending unit and it is located right next to the T-stat (just passenger side to it).

Next you should reset the instrument cluster to ensure that it is reading properly. Search for the instructions under my name.