Isuzu N-Series. Manual - part 343

6A3-24 ENGINE (4HF1 / 4HF1-2 / 4HE1-TC / 4HG1 / 4HG1-T)

4HE1-TC (98EPA)

EXHAUST GAS RECIRCULATION SYSTEM (EGR)

Component

Removal

1. EGR pipe assembly
2. EGR valve

Installation

1. EGR valve

Insert the gasket and install the EGR valve to the
intake manifold.

Notice:
The gasket of 4HE1-XS and 4HE1-XN are dirrerent.

Tighten:
EGR valve bolt to 23.5 

± 5 N⋅m (2.4 ± 0.5 kg⋅m/17 ± 3.7

lb

⋅ft)

Legend

1. EGR pipe assembly

2. EGR valve

N6A1601E

ENGINE (4HF1 / 4HF1-2 / 4HE1-TC / 4HG1 / 4HG1-T) 6A3-25

2. EGR Pipe assembly

Install the EGR pipe assembly to the exhaust man-
ifold and the EGR valve with gasket.

Tighten:
A: Bolt to 23.5 

± 5 N⋅m (2.4 ± 0.5 kg⋅m/17 ± 3.7 lb⋅ft)

B: Nut to 28.4 

± 4 N⋅m (2.9 ± 0.4 kg⋅m/21 ± 3.1 lb⋅ft)

C: Bolt to 23.5 

± 5 N⋅m (2.4 ± 0.5 kg⋅m/17 ± 3.7 lb⋅ft)

Legend

1. EGR valve
2. Inlet case

N6A0405E

A

C

B

N6A1602E

6A3-26 ENGINE (4HF1 / 4HF1-2 / 4HE1-TC / 4HG1 / 4HG1-T)

EXHAUST MANIFOLD

Component

Removal

Preparation

• Disconnect battery ground cable.
• Tilt the cab.

1. Air Conditioning (A/C) Compressor (If equipped

with A/C)
1) Disconnect magnetic clutch harness connec-

tor.

2) Dismount the compressor together with the

hoses from the A/C compressor bracket, and
fasten it to the appropriate location with a wire.

2. A/C Compressor Bracket (If equipped with A/C)
3. Front Exhaust Pipe
4. Heat Protector
5. Exhaust Manifold
6. Exhaust Gasket

Legend

1. A/C compressor (If equipped with A/C)

4. Heat protector

2. A/C compressor bracket (If equipped with A/C)

5. Exhaust manifold

3. Front exhaust Pipe

6. Exhaust gasket

N6A0411E

ENGINE (4HF1 / 4HF1-2 / 4HE1-TC / 4HG1 / 4HG1-T) 6A3-27

Installation

1. Exhaust Gasket

Insert the gasket into the stud provided to the cyl-
inder head (with the projection (1) of the gasket on
this side).

2. Exhaust Manifold

1) Install exhaust manifold gaskets (1), exhaust

manifold (2), distance pieces (3), dish washers
(4) and nuts (5) to the stud bolts shown in the
illustration.

2) Tighten the nuts to the specified torque in the

numerical order shown in the illustration.

Tighten:
Exhaust manifold nut to 34 N

⋅m (3.5 kg⋅m/25 lb⋅ft)

3. Heat Protector

Tighten:
Heat protector bolt to 10 N

⋅m (1.0 kg⋅m/7 lb⋅ft)

4. Front Exhaust Pipe

Tighten:
Front exhaust pipe to

• Exhaust manifold side: 67 N

⋅m (6.8 kg⋅m/49 lb⋅ft)

• Exhaust brake side: 17 N

⋅m (1.7 kg⋅m/12 lb⋅ft)

5. Air Conditioning (A/C) Compressor Bracket (If

equipped with A/C)
Tighten fixing bolts to the specified torque.

Tighten:
A/C compressor bracket bolt to 48 N

⋅m (4.9 kg⋅m/35

lb

⋅ft)

N6A0412E

N6A0413E

N6A0414E

N6A0415E