New MotoRad thermostat.  This is a 160 degree thermostat, and is a low temperature thermostat, stock replacement.  Please be advised that a 160 degree thermostat does not make the motor run at 160 degrees, it only opens at 160 degrees, which means the thermostat will open 20 degrees earlier vs a 180 degree thermostat and 35 degrees earlier vs a 195 degree thermostat, which typically allows the motor to run cooler. Fits the following:

86-87 Buick Regal T-Type/Grand National w/ V6 Turbo