Toyota 3R-B 1969, Repair Manual

Page: 135 / 193

7 — 8 C O O L I N G S Y S T E M — Thermostat
T H E R M O S T A T
Description
T h e thermostat equipped on the R S and R T s e r ie s is of a wax type, and a bel­
low type is equipped on the R K s e r ie s .
T h e thermostat is installed within the thermostat chamber of the w ater pump,
which restricts the coolant flow into the radiator. T h u s, the engine warm-up
period is minimized, and maintains engine economical operating temperature.
T h e w ax type thermostat has the following excellent features.
1. A s it is not affected by w a te r p r e s s u r e , it ensures positive operation, and
w a te r leak is slight when the valve is closed.
2. A s the w a te r flow resistance is small on the thermostat, the w a te r flow into
the radiator is la r g e .
3. T h e construction is v e r y durable, and the life of the thermostat is prolonged
due to no valve vibration.
4. It is heat-p roof, co ld -p ro o f and p r e s s u r e - p r o o f .
Specification:
T y p e
Starts to open at
Fully opens at
V a lv e lift
F o r R S & R T s e r ie s
Wax
80.5 ~ 8 3 . 5 °C
(177 ~ 1 8 2 ° F )
9 5 °C ( 2 0 3 ° F )
8 mm (0 .3 15 " )
W ax C a s e
C lo s e d
F o r R K s e rie s
Bellow s
63.5 ~ 6 6 . 5 °C
(146 ~ 151 ° F )
73°C (1 9 4 ° F )
8 mm (0.3 15" )
S h a f t
W ax
R em oval
F i g . 7-15 Wax T y p e Therm ostat Operation
Inspection
G1690
G1500
1. D rain the coolant,
a n d
r e m o v e the
w a te r pump outlet h ose .
2. R e m o v e the w a te r outlet, and then
re m o v e the thermostat.
1., R ep lac e the thermostat if the valve
is opened at normal tem p eratu re.
2. S u b m erge the thermostat into the
w a t e r , and raise the w a te r temp­
eratu re gradually to check the
va lve opening tem peratu re.