Dodge Dakota (R1). Manual - part 255

tion with the radiator pressure cap. It utilizes ther-
mal expansion and contraction of coolant to keep
coolant free of trapped air. It provides a volume for
expansion and contraction of coolant. It also provides
a convenient and safe method for checking coolant
level and adjusting level at atmospheric pressure.
This is done without removing the radiator pressure
cap. The system also provides some reserve coolant
to the radiator to cover minor leaks and evaporation
or boiling losses.

As the engine cools, a vacuum is formed in the

cooling system of both the radiator and engine. Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.

ENGINE BLOCK HEATER -
3.9L/5.9L

DESCRIPTION

WARNING: DO NOT OPERATE ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
THE POWER CORD MUST BE SECURED IN ITS
RETAINING

CLIPS AND

ROUTED AWAY

FROM

EXHAUST MANIFOLDS AND MOVING PARTS.

An optional engine block heater is available on all

models. The heater is equipped with a power cord.
The heater is mounted in a core hole of the engine
cylinder block (in place of a freeze plug) with the
heating element immersed in engine coolant. The
cord is attached to an engine compartment compo-
nent with tie-straps.

The 3.9L and 5.9L gas powered engine has the

block heater located on the right side of engine next
to the oil filter (Fig. 2).

Fig. 1 Upper Fan Shroud with Integral Coolant

Recovery Container

1 - RADIATOR
2 - WASHER FLUID RESERVOIR
3 - COOLANT OVERFLOW/RESERVOIR
4 - FAN SHROUD (UPPER)
5 - SCREW
6 - INTERLOCKING PINS
7 - FAN SHROUD (LOWER)

Fig. 2 Engine Block Heater

1 - FREEZE PLUG HOLE
2 - BLOCK HEATER
3 - SCREW
4 - POWER CORD (120V AC)
5 - HEATING COIL
6 - OIL FILTER

ENGINE

7 - 33

OPERATION

The heater warms the engine coolant providing

easier engine starting and faster warm-up in low
temperatures.

Connecting

the

power

cord

grounded 110-120 volt AC electrical outlet with a
grounded three wire extension cord provides the elec-
tricity needed to heat the element..

REMOVAL

(1) Disconnect battery negative cable.
(2) Drain coolant (Refer to 7 - COOLING - STAN-

DARD PROCEDURE).

(3) Remove power cord from heater by unplugging

(Fig. 3).

(4) Loosen (but do not completely remove) the

screw at center of block heater (Fig. 3).

(5) Remove block heater by carefully prying from

side-to-side. Note direction of heating element coil
(up or down). Element coil must be installed correctly
to prevent damage.

INSTALLATION

(1) Clean and inspect the block heater hole.
(2) Install new O-ring seal(s) to heater in gasoline

engines.

(3) Insert block heater into cylinder block.

(4) With heater fully seated, tighten center screw

to 2 N·m (17 in. lbs.).

(5) Fill cooling system with recommended coolant.

(Refer to 7 - COOLING - STANDARD PROCE-
DURE).

(6) Start and warm the engine.
(7) Check block heater for leaks.

ENGINE BLOCK HEATER - 4.7L

DESCRIPTION

WARNING: DO NOT OPERATE ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
THE POWER CORD MUST BE SECURED IN ITS
RETAINING

CLIPS AND

ROUTED AWAY

FROM

EXHAUST MANIFOLDS AND MOVING PARTS.

An optional engine block heater (Fig. 4) is avail-

able with all models. The heater is equipped with a
power cord. The cord is attached to an engine com-
partment component with tie-straps. The heater
warms the engine providing easier engine starting
and faster warm-up in low temperatures. The heater
is mounted in a core hole of the engine cylinder block
in place of a freeze plug with the heating element
immersed in engine coolant.

Fig. 3 Engine Block Heater

1 - FREEZE PLUG HOLE
2 - BLOCK HEATER
3 - SCREW
4 - POWER CORD (120V AC)
5 - HEATING COIL
6 - OIL FILTER

Fig. 4 Engine Block Heater—4.7L

1 - ENGINE BLOCK HEATER

7 - 34

ENGINE

ENGINE BLOCK HEATER - 3.9L/5.9L (Continued)

OPERATION

Connecting the power cord to a grounded 110-120

volt AC electrical outlet with a grounded, three wire
extension cord activates the heating element warm-
ing the engine coolant.

DIAGNOSIS AND TESTING—ENGINE BLOCK
HEATER

If the unit does not operate (Fig. 5), possible causes

can be either the power cord or the heater element.
Test the power cord for continuity with a 110-volt
voltmeter or 110-volt test light. Test heater element
continuity with an ohmmeter or a 12-volt test light.

CAUTION: To prevent damage, the power cord must
be secured in it’s retainer clips and away from any
components that may cause abrasion or damage,
such as linkages, exhaust components, etc.

REMOVAL

(1) Disconnect negative battery cable from battery.
(2) Drain coolant from radiator (Refer to 7 -

COOLING - STANDARD PROCEDURE).

(3) Raise vehicle.
(4) Remove engine cylinder block drain plug(s)

located on the sides of cylinder block above the oil
pan rail (Fig. 6).

(5) Remove power cord from block heater.
(6) Loosen screw at center of block heater. Remove

heater assembly (Fig. 7).

INSTALLATION

(1) Thoroughly clean cylinder block core hole and

block heater seat.

Fig. 5 Engine Block Heater 4.7L Engine

1 - ENGINE BLOCK HEATER

Fig. 6 Drain Plug - 4.7L Engine

1 - CYLINDER BLOCK DRAIN PLUG
2 - EXHAUST MANIFOLD AND HEAT SHIELD

Fig. 7 Engine Block Heater - 4.7L

1 - ENGINE BLOCK HEATER

ENGINE

7 - 35

ENGINE BLOCK HEATER - 4.7L (Continued)

Content .. 253 254 255 256 ..