It is quite easy to change the thermostat in your 1990 Cutlass. Remove the thermostat housing retaining bolts. Remove the thermostat from the housing. Reverse the process to install the new thermostat.
On the 3.3L V6 it is under the radiator cap.
Engine end of upper radiator hose
On a 1989 Oldsmobile Cutlass Ciera with a 3.3-liter V6 engine, the thermostat is located on the engine block at the end of the upper radiator hose. To access it, you'll need to remove the hose from the thermostat housing. Once the housing is exposed, you can unscrew it to replace the thermostat. Make sure to allow the engine to cool before starting this process to avoid burns.
The 1993 Oldsmobile Cutlass Sierra thermostat is located on the front of the engine. You can follow the water supply line from the radiator to the thermostat housing.
On a 1989 Oldsmobile Cutlass Ciera with a 3.3L motor, the thermostat is located near the engine block, typically at the end of the upper radiator hose. To access it, follow the upper hose to where it connects to the engine, which is where the thermostat housing is situated. You'll need to remove the housing to replace the thermostat. Make sure to allow the engine to cool and drain some coolant before starting the procedure.
Should be in a removable housing at the engine end of the upper radiator hose
can i reset it or replace it ,where is it on the car
The ECM is located behind the glovebox on a 1991 Cutlass Ciera. Pull the glove box out to see it. Once located remove the mounting hardware and unplug it from the car. Replace the unit.
yes, most of the panels can be used from one to the other
follow the top radiator hose where it goes back to the egine
Yes, you do.