Isuzu N-Series. Manual - part 378

6B-6 ENGINE COOLING

WATER PUMP

Component

Removal

Preparation

• Disconnect battery ground cable.
• Drain coolant.
• Tilt the cab.

1. Radiator Lower Hose

Disconnect radiator Lower hose from radiator.

Legend

1. Radiator lower hose

4. Fan belt

2. Fan guide

5. Water pump pulley

3. Fan

6. Water pump assembly

N6A0796E

N6A0797E

ENGINE COOLING 6B-7

2. Fan Guide
3. Fan

4. Fan Belt
5. Water Pump Pulley
6. Water Pump Assembly

Inspection

Make the necessary adjustments, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.

Water Pump Assembly

1. Check the pump body for crack and damage.
2. Check the impeller for crack and corrosion.
3. Check the seal unit leakage.
4. If there is any abnormal condition, replace the wa-

ter pump as an assembly.

Bearing Unit

1. Rotate the fan center while pushing it toward the

radius, and check to see if there is any excessive
play or noise.

2. When there is any excessive play or noise found,

replace it as a water pump assembly.

Installation

1. Water Pump Assembly

1) Apply 3 — 4 mm (0.12 — 0.16 in) bead of the

recommended liquid gasket (Three Bond
1207C) or its equivalent on the water pump fit-
ting surface.

2) Install the water pump to the front retainer.

Tighten:
Water pump bolt to 24 N

⋅m (2.4 kg⋅m / 17 lb⋅ft)

• Install the water pump within 7 minutes after appli-

cation of liquid gasket.

• For the dislocation of liquid gasket, refer to the il-

lustration.

N6A0798E

N6A0799E

N6A0800E

N6A1625E

6B-8 ENGINE COOLING

Caution:
The water pump clamping bolt is also used to tighten the
front retainer. So, install the water pump before liquid
gasket gets dry immediately after installation of the front
retainer.

2. Water Pump Pulley

Tighten:
Water pump pulley bolt to 24 N

⋅m (2.4 kg⋅m / 17 lb⋅ft)

3. Fan Belt

Check the drive belt tension.
Depress the drive belt mid-portion with a 98 N
(10 kg / 22 lb) force.

Check the drive belt for cranking and other dam-
age.

Fan Belt Adjustment
Fan belt tension is adjusted by moving the generator.

Tighten:
Bolt to

• (1): 40 N

⋅m (4.1 kg⋅m / 30 lb⋅ft)

• (2): 24 N

⋅m (2.4 kg⋅m / 17 lb⋅ft)

• (3): 46 N

⋅m (4.7 kg⋅m / 34 lb⋅ft)

4. Fan

Tighten:
Fan bolt to 24 N

⋅m (2.4 kg⋅m / 17 lb⋅ft)

5. Fan Guide
6. Radiator Lower Hose

• Pour coolant into radiator.
• Connect battery ground cable.
• Start engine and check for water leakage carefully.

Legend

1. Liquid gasket

Legend

1. Set plate
2. Pulley

Drive Belt Deflection

mm (in)

New belt

8 — 12 (0.31 — 0.47)

Reuse belt

10 — 14 (0.39 — 0.55)

N6A0802E

N6A0037E

N6A0038E

ENGINE COOLING 6B-9

THERMOSTAT

Component

Removal

Preparation

• Disconnect battery ground cable
• Drain coolant

1. Radiator Upper Hose

Disconnect radiator upper hose from radiator.

2. Water Outlet Pipe

Remove mounting bolt and remove outlet pipe to-
gether with radiator upper hose.

3. Thermostat

Inspection

Make the necessary adjustments, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.
Operating Test

1. Completely submerge the thermostat in water.
2. Heat the water.

Stir the water constantly to avoid direct heat being
applied to the thermostat.

3. Check the valve initial opening temperature.

Legend

1. Radiator upper hose

3. Thermostat

2. Water outlet pipe

N6A0805E