Chevrolet 10 Series 1970 Service Manual page 363

F ig . 2 — Pressure C h e c k in g R adia tor Cap
rubber sea l on cap fo r te a rs or cracks.
cap on te s te r (fig. 2). If the p ressu re cap w ill not hold
p res su re o r does not r e le a s e at the p rop er p ressu re,
rep la ce the cap.
Cylinder Block and C ylinder Head
1. W ith the therm ostat rem oved, attach a lead-aw ay
hose to the w ater pump inlet and a length of new hose
to the w ater outlet connection at the top o f the engine.
NOTE: Disconnect the
connections at engine
engine.
2. In sert the flushing gun in the new hose.
3. Turn on the w ater and when the engine w ater jacket
is full, turn on the a ir in short blasts.
4. Continue this flushing until the w ater from the lead-
away hose runs c le a r.
Heater Core
1. R em ove w ater outlet hose fro m
2. R em ove in let hose fro m engine connection.
3. In sert flushing gun and flush heater core.
be taken when applying a ir p ressu re to prevent dam­
age to the core.
Fan Belt Adjustm ent
1. Loosen bolts at D elcotron mounting.
2. P u ll D elcotron away fro m engine until d esired ten­
sion reading is obtained with a strand tension gauge.
R e fe r to "E ngine Tune Up S p ecification s".
3. Tighten a ll D elcotron bolts secu rely.
Thermostat
The therm ostat consists of a re s tric tio n valve actuated
by a therm ostatic elem ent.
ing at the cylin d er head w ater outlet above the w ater
pump. Th erm ostats a re designed to open and close at
p red eterm in ed tem p eratu res and i f not operating p ro p erly
should be rem oved and tested as follow s:
Replacement
1. Rem ove radiator to w ater outlet hose.
2. Rem ove therm ostat housing bolts and rem ove w ater
outlet and gasket fro m therm ostat housing (fig. 3).
Install radiator
heater hose and cap
when re v e r s e flushing
heater core pipe.
Care must
This is mounted in the hous­
F ig . 3 — R epla cing Therm ostat
3. Inspect therm ostat valve to make sure it is in good
condition.
4. P la ce therm ostat in hot w ater 25° above the te m p e r­
ature stamped on the therm ostat valve.
5. Submerge the valve com pletely and agitate the w ater
thoroughly. Under this condition the valve should
open fully.
6. Rem ove the therm ostat and place in w ater 10° below
tem perature indicated on the valve.
7. With valve com pletely subm erged and w ater agitated
thoroughly, the valve should close com pletely.
8. If therm ostat checks sa tisfa cto rily , re -in s ta ll, using
a new housing gasket.
9. R e fill cooling system .
W a te r Pump
Removal
1. Drain radiator and break loose the fan pulley bolts.
2. Disconnect heater hose, low er radiator hose and
by pass hose (as requ ired) at w ater pump.
3. Loosen D elcotron and rem ove fan belt then rem ove
fan bolts, fan and pulley.
NOTE: Th erm ostatic fan clutches must be kept
in an " in - c a r " position.
the car the assem bly should be supported so
that the clutch disc rem ains in a v e rtic a l plane
to prevent silico n e fluid leakage.
4. Rem ove pump to cylin der block bolts and rem ove
pump and old gasket from engine.
NOTE: On in line
straight out of the block fir s t, to avoid damage
to im p e lle r.
Installation
1. Install pump assem bly on cylin der block then, using
a new s e a le r coated pum p-to-block gasket tighten
bolts secu rely.
ENGINE COOLING 6K-3
When rem oved fro m
engines, pull the pump
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