If the valve is open, replace the thermostat with a new one.

The thermostat must be completely submerged and must not touch the container sides or bottom. Suspend an accurate thermometer [B] in the water so that the heat sensitive portions [C] are located in almost the same depth.
It must not touch the container, either.
If the measurement is out of the specified range, replace the thermostat with a new one.
Thermostat Valve Opening Temperature
58
62°C (136
144°F)

Thermostat Installation
Hoses and PipesStarter Clutch Assembly
Install the one-way clutch [A] to the driven gear.
Face the circlip side of the one-way clutch to inside.
Install the new snap ring [B] to the one-way clutch.
Install the drive gear [C] while turn it counterclockwise [D].
Apply molybdenum disulfide oil solution to the needle
bearing ...
Fuel Tank Cap
To open the fuel tank cap, pull up the
key hole cover. Insert the ignition key
into the fuel tank cap and turn the key
to the right.
To close the cap, push it down into
place with the key inserted. The key
can be removed by turning it to the left
to the original position. Close the key
hol ...
Reporting safety defects
(For Products Sold in the United States of America, District of Columbia,
and
U.S. Territories Only)
If you believe that your vehicle has a defect which could cause a crash or
could
cause injury or death, you should immediately inform the National Highway
Traffic
Safety Administration (NHT ...