The thermostat is located on a 2003 Oldsmobile Alero in the thermostat housing. The thermostat housing is located on the rear side of the engine block.
Its on the engine near the thermostat
Need to know if you have the 2.2 or the 3.4 engine.
Usually in a removable housing at the engine end of the upper radiator hose
it is inside the thermostat housing, which is where the upper radiator hose connects to the engine. the metal that the hose clamps to is the housing.
i have a 2001 olds alero 3.4 V6 and the thermostat on mine is underneath the throttle body...this may vary from your '99 vehicle, and it also may vary depending on your engine size
Follow the upper radiator hose to the engine. It should be located in a housing near where the hose connects to the engine.
Rear of engine, underneath the exhaust manifold. you can follow the coolant line (approx. 2") tha runs underneath your engine, then runs up the back of the engine, up to the thermostat.
In the 2000 Alero, it is fuse 34 in the engine fuse box, which is located near the battery. You can check the same fuse for the 1999 Alero and see if that is it.
you need to remove air filter and some of the exhaust pipe before u can get at it.
beside thermostat
is the 2000 Oldsmobile alero 2.4 l a good engine