C-15 On-Highway Engine Caterpillar

A general visual inspection should be made to the air inlet and exhaust system. Make sure that there are no signs of leaks in the system.

Table 1

Tools Needed
Part Number	Part Name	Quantity
1U-5470	Engine Pressure Group	1

Illustration 1	g00295554
1U-5470 Engine Pressure Group

Air Inlet Restriction

There will be a reduction in the performance of the engine if there is a restriction in the air inlet system.

1. Inspect the engine air cleaner inlet and ducting in order to ensure that the passageway is not blocked or collapsed.

2. Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element.

3. Check for dirt tracks on the clean side of the engine air cleaner element. If dirt tracks are observed, contaminants are flowing past the engine air cleaner element and/or the seal for the engine air cleaner element.

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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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Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts. When working on an engine that is running, avoid contact with hot parts and rotating parts.

4. Use the differential pressure gauge of the 1U-5470 Engine Pressure Group .
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   Illustration 2	g00808208
   Air inlet piping (1) Air Cleaner (2) Test location (3) Turbocharger

   1. Connect the vacuum port of the differential pressure gauge to test location (2). Test location (2) may be located anywhere along the air inlet piping after air cleaner (1) but before turbocharger (3) .

   2. Leave the pressure port of the differential pressure gauge open to the atmosphere.

   3. Start the engine. Run the engine in the no-load condition at high idle.

   4. Record the value.

   5. Multiply the value from Step 4.d by 1.8.

   6. Compare the result from Step 4.e to the appropriate values that follow.

The air flow through a used engine air cleaner may have a restriction. The air flow through a plugged engine air cleaner will be restricted to some magnitude. In either case, the restriction must not be more than the following amount:

Maximum restriction ... 6.2 kPa (25 in of H₂O)

The air flow through a new engine air cleaner element must not have a restriction of more than the following amount:

Maximum restriction ... 3.7 kPa (15 in of H₂O)

Exhaust Restriction

There will be a reduction in the performance of the engine if there is a restriction in the exhaust system.

These engines use an catalytic converter that is used to reduce the exhaust emissions. The catalytic converter will cause a slight increase in exhaust back pressure. This is normal. Do not remove the catalytic converter or modify the catalytic converter for any reason. The catalytic converter may need to be removed in some cases in order to be serviced, but the catalytic converter must be on the vehicle before the vehicle is sent back into service.

Back pressure is the difference in the pressure between the exhaust at the outlet of the turbocharger and the atmospheric air.

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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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Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts. When working on an engine that is running, avoid contact with hot parts and rotating parts.

Use the differential pressure gauge of the 1U-5470 Engine Pressure Group in order to measure back pressure from the exhaust. Use the following procedure in order to measure back pressure from the exhaust:

Illustration 3	g00910447
Typical example Exhaust piping (1) Catalytic converter (2) Test location (3) Turbocharger

1. Connect the pressure port of the differential pressure gauge to test location (2). Test location (2) can be located anywhere along the exhaust piping after turbocharger (3) but before the catalytic converter (1) .

2. Leave the vacuum port of the differential pressure gauge open to the atmosphere.

3. Start the engine. Run the engine in the no-load condition at high idle.

4. Record the value.

5. Multiply the value from Step 4 by 1.8.

6. Compare the result from Step 5 to the value that follows.

Back pressure from the exhaust must not be more than the following amount:

Maximum back pressure ... 15 kPa (60 inch of H₂O)