I've never worked on a Nissan, but on domestic vehicles ,yes, the spring would be down (or toward the block) good luck friend-mannsvillain
how to change a thermostat on a 1990 Nissan pintara
it is on the front of the engine block behind the fan. looking at the car from the front it is to the left of the water pump. there will be a three bolt adapter going from the engine block to the radiator. by removing the three bolts you will find the thermostat there.
1990 Camry 4 cylinder thermostat is located off the bottom intake hose connected to the engine block.
at end of top of radiator hose.
follow your top radiator hose,its in the thermostat cover,two bolts hold it on.
spring goes toward engine
If you follow the lower radiator hose to the engine block, it will lead you towards the thermostat housing (inside there is the thermostat),
Just follow the top hose, from the radiator, to the engine block. It will be at the end, on the engine block
The thermostat is located on the RH side (passenger side) of the engine, toward the front. A radiator hose goes into a housing. Looking down from the top, there are (normally) two sensors going into the housing. The thermostat is below these and the cover is held onto the block with three bolts. If you replace it, go with an original Nissan brand. It's worth any extra cost.
should eather be at the top in to engine or on bottom hose coming from engine
temperature guage sending unit
Usually in a removable housing at the engine end of the upper radiator hose