Converting a Four Cylinder Air Compressor Air Supply From a Pressurized Air Supply to a Naturally Aspirated Air Supply{1803} Caterpillar

On-Highway Engine:

3176 (S/N: 2YG1-UP; 7LG1-UP)

3176B (S/N: 9CK1-UP)

C-10 (S/N: 2PN1-UP; 3CS1-UP; 8YS1-UP)

C-12 (S/N: 8YF1-UP; 1YN1-UP; 2KS1-UP; 9NS1-UP)

Introduction

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Before you disconnect any line from the air compressor, purge the system of pressurized air. Failure to purge the pressurized air before you service the air compressor can result in personal injury.

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Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.

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Personal injury can result from rotating and moving parts. Stay clear of all rotating and moving parts. Never attempt adjustments while the machine is moving or the engine is running unless otherwise specified. The machine must be parked on a level surface and the engine stopped.

These truck engines may be equipped with a four cylinder air compressor. The air supply for the air compressor may come from the engine air inlet manifold. The air in the engine air inlet manifold is pressurized. The pressurized air supply requires the air compressor to have an inlet regulating valve. The inlet regulating valve must be maintained at every 48,280 kilometers (30,000 miles). The inlet regulating valve will be eliminated when you convert the air supply for the air compressor to a naturally aspirated air supply. This publication describes the requirements for converting the air supply of the air compressor from a pressurized air supply to a naturally aspirated air supply.

Converting the air supply for the air compressor from a pressurized air supply to a naturally aspirated air supply may require the following items. The diameter of the air piping on the vehicle will determine the parts that may be required.

The following list is for vehicles with air piping with a diameter of 152 mm (6.0 inch).

• 105-1175 Hose (Qty 2)

• 3E-7424 Hose Clamp (Qty 8)

• 166-6339 Air Pipe Assembly (Qty 1)

• 7X-7958 Hose Clamp (Qty 2)

• 5N-7444 Hose (Qty 1)

• 9S-8008 O-Ring Plug (Qty 1)

• 6V-5063 O-Ring Seal (Qty 1)

• 7W-1890 Elbow (Qty 1)

Note: A straight 053-2313 Connector may be used instead of the 7W-1890 Elbow .

The following list is for vehicles with air piping with a diameter of 127 mm (5.0 inch).

• 4W-7731 Reducer Hose (Qty 2)

• 3E-7424 Hose Clamp (Qty 2)

• 8T-4987 Hose Clamp (Qty 2)

• 166-6339 Air Pipe Assembly (Qty 1)

• 7X-7958 Hose Clamp (Qty 2)

• 5N-7444 Hose (Qty 1)

• 9S-8008 O-Ring Plug (Qty 1)

• 6V-5063 O-Ring Seal (Qty 1)

• 7W-1890 Elbow (Qty 1)

Note: A straight 053-2313 Connector may be used instead of the 7W-1890 Elbow .

Procedure for Removal of Pressurized Air Supply

Illustration 1	g00598563
(1) Hose assembly (2) Inlet regulating valve (3) Hose clip (4) Fitting (5) Fitting (6) Fitting

1. Remove any hose clips (3). Save the clips for later use.

2. Remove hose assembly (1) that connects the air compressor inlet manifold to the engine air inlet manifold.

3. Remove inlet regulating valve (2) .

4. Remove any fittings (4) that connected the hose assembly to the air compressor inlet manifold.

5. Remove any fittings (5), or (6), that connected the hose assembly to the air compressor inlet manifold.

Procedure for Installation of Naturally Aspirated Air Supply on Vehicles With 152 mm (6.0 inch) Air Piping

Illustration 2	g00599481
Naturally aspirated air supply with 152 mm (6.0 inch) air piping

1. Install plug (6) and seal (7) in the engine air inlet manifold.

2. Determine a location in the inlet air piping in order to install air pipe assembly (3). Install the air pipe assembly close to the air cleaner.

Note: When possible, use existing air hoses and clamps. Avoid installing additional air hoses in the inlet air piping.

3. Cut air pipe assembly (3) in order to fit the inlet air piping. Remove any burrs from air pipe assembly (3) .

4. Install air pipe assembly (3) in the air piping. Use hoses (1), if necessary. Use clamps (2), if necessary. Use two hose clamps on each end of hose (1). Refer to illustration 2.

5. Install the 90 degree elbow (8) in the air compressor inlet manifold. A straight connector may be used in place of the 90 degree elbow. Refer to footnote 1 in Table 1.

6. Install hose (5) on 90 degree elbow (8) on the air compressor. Secure hose (5) with hose clamp (4) .

7. Route hose (5) to air pipe assembly (3). Cut off excess length of hose (5), if necessary.

8. Install hose (5) on the fitting on the air pipe assembly (3). Secure hose (5) with hose clamp (4) .

Procedure for Installation of Naturally Aspirated Air Supply on Vehicles With 127 mm (5.0 inch) Air Piping

Illustration 3	g00599483
Naturally aspirated air supply with 127.0 mm (5 inch) air piping

1. Install plug (7) with seal (8) in the engine air inlet manifold.

2. Determine a location in the inlet air piping in order to install air pipe assembly (4). Install the air pipe assembly (4) close to the air cleaner.

Note: When possible, use existing air hoses and clamps. Avoid installing additional air hoses in the inlet air piping.

3. Cut air pipe assembly (4) in order to fit the inlet air piping. Remove any burrs from air pipe assembly (4) .

4. Install air pipe assembly (4) in the air piping. Use hoses (1) ,as needed. Use clamps (2) and (3), as needed.

5. Install the 90 degree elbow (9) in the air compressor inlet manifold. A straight connector may be used in place of the 90 degree elbow. Refer to footnote 1 in Table 2.

6. Install hose (6) on 90 degree elbow (9) on the air compressor. Secure hose (6) with hose clamp (5) .

7. Route hose (6) to air pipe assembly (4). Cut off excess length of hose (6), if necessary.

8. Install hose (6) on the fitting on the air pipe assembly (4). Secure hose (6) with hose clamp (5) .