Series 40E Troubleshooting – Section 11.8 Intake Restriction

Figure 1. Diagnostic Form

Follow this procedure to determine if an intake/air cleaner restriction is excessive. For a reproduction of the applicable portion of the diagnostic form, see Figure
“Diagnostic Form”

.‪

Section 11.8.1
Purpose

Often a low power and poor fuel economy complaint is simply due to a dirty air cleaner element. In this test, the gage is inserted into the air cleaner housing. As the air cleaner element accumulates dirt, restriction to airflow increases. If restriction exceeds specifications, replace the air cleaner element or elements.‪

Note: A high intake restriction may cause a considerable amount of black or blue smoke when starting the engine.

Section 11.8.2
Air Intake Restriction Indicator

Inspect the air intake restriction indicator.‪

1. Refer to appropriate OEM guides for air cleaner information.
2. Inspect the element(s) for damaged gaskets or dents. If they exhibit either, they should be replaced.
3. Inspect inlet piping for debris.

Section 11.8.2.1
Single Element Air Cleaner

Measure air cleaner restriction as follows:‪

1. Attach the restriction test gage at the air cleaner housing tap location. See Figure
   “Restriction Test, Tap Location”.
   

   Figure 2. Restriction Test, Tap Location

2. Run engine at high idle r/min.
3. Replace the air cleaner element when the test gage measures a restriction greater than 12.5 in. H₂
   O (3.13 kPa).

Note: The true maximum air cleaner restriction can only be obtained when operating the engine at full load and rated speed. The vehicle mounted indicator or vacuum gage will sense maximum restriction. When 25 in. H₂
O (6.22 kPa) is sensed on the vehicle mounted gages, replace the air cleaner element. For convenience, air cleaner restriction can be measured at high idle (no load). However, the element must be replaced when 12.5 in. H₂
O (3.13 kPa) is measured at no load.

Note: High air cleaner restriction can cause turbocharger seals to unseat, causing oil to be drawn through the seals and into the engine.

Section 11.8.2.2
Dual Element Air Cleaner

The dual element air cleaner provides a large primary (outer) filter element and an optional small, secondary (inner) filter element. The secondary element should be used in dusty environments.‪

The dual element air cleaner assembly restriction connection is located between the primary and the secondary element in the bottom of the air cleaner housing. This arrangement allows only the primary (outer) element to be sensed by the restriction indicator or dash-mounted vacuum gage. The inner element is not recorded on the restriction indicator or dash-mounted vacuum gage. See Figure
“Dual Element Air Cleaner with Indicator in End Cap”

. See Figure
“Dual Element Air Cleaner Retaining Nut Indicator”

. ‪

1. Secondary (Inner Element)‪	3. Inner Element Restriction Indicator‪
2. Air Cleaner Housing‪	‪

Figure 3. Dual Element Air Cleaner with Indicator in End Cap

1. Secondary (Inner Element)‪	3. Inner Element Retaining Nut with Restriction Indicator‪
2. Air Cleaner Housing‪	‪

Figure 4. Dual Element Air Cleaner Retaining Nut Indicator

To determine inner element restriction, use the visual check procedure.‪

Visually inspect the restriction indicator built into the inner element or inner element retaining nut.‪

Note: Two different indicators are the result of two different suppliers. Replace the element when the green dot disappears from the element or from the window in the retaining nut. Each supplier’s retaining nut requires a different torque. See Figure
“Dual Element Air Cleaner with Indicator in End Cap”

. See Figure
“Dual Element Air Cleaner Retaining Nut Indicator”

.

Section 11.8.3
Possible Causes

Possible causes for the problem include:‪

• Dirty air cleaner element.
• Snow, plastic bags or other foreign material may restrict airflow at the air cleaner inlet. On engines recently repaired, rags or cap plugs may have been inadvertently left in the intake system.

Section 11.8.4
Tools Required

Engine Field Test Kit J 39257
, and magnehelic gauge or water manometer‪