Should be spring side down most engines. The bi metal parts that cause it to open are generally on that side and have to be exposed to the coolant so it operates at correct temp.
Vrey carefully
By the thermostat
In the motor.
to keep the hose from collapsing
Stuck thermostat, scale build up in the radiator and engine block, radiator cap not holding correct pressure. or it could be your headgaskets
Usually at engine end of upper radiator hose in housing
near the thermostat housing
located n housing at end of upper radiator hose.
p205 70/r15
t.h.440/ early 4t60
A Cadillac Deville can be purchased at a Cadillac dealer.
On a 2000 Cadillac DeVille, the thermostat is located in the engine compartment, specifically at the engine's coolant outlet. To access it, you typically need to remove the upper radiator hose and the thermostat housing, which is usually bolted to the engine. It's advisable to consult the vehicle's service manual for specific details and diagrams.