97 Chevy Tahoe over heating

Was it overheating before the new thermostat? Could be in backwards. Air in the system. Make sure your sending unit for the gauge is good. Fan clutch bad, radiator plugged.

Like the response above, what prompted you to change your thermostat? Thermostats can be placed in upside down, so when they get hot, they close and water does not flow to the radiator to cool. Your Tahoe is not that old, but is there water/fluid flow. A radiator blockage is possible but not really probable unless yuou have been using only water in the cooling system. Also do you live in the cold weather climate? If the antifreeze is not correct, you have a frozen radiator and block. Is the over heating new after the new thermostat? Please give us more to work with and we will try to help.

Same thing happened with my 98 Chevy Tahoe 5.7 liter 350 v8started overheating moisture water vapor coming out of tailpipe I pulled spark plugs to see if water was in the cylinders and yes there was water inside cylinder number three and six so that told me I had to cracked engine heads so I removed the entire top end of the motor Told me that the heads and found out that yes there were cracks

cloged rad. or bad finns on water pump or blockage in block. Im having the same problem with my 97. I will let you know when I finger it out. lol.