C15 and C18 – Inspect Air Inlet Restriction

Refer to Special Instruction, SEHS8907, “Using the 1U-5470 Engine Pressure Group ” for the instructions that are needed to use the 1U-5470 Engine Pressure Group. Refer to Operation Manual, NEHS0818, “Using the 198-4240 Digital Pressure Indicator ” for the instructions that are needed to use the 198-4240 Digital Pressure Indicator .

  1. Check the Air Filter Change Indicator Group on the air inlet for a reading of the restriction.
  2. Inspect the engine air cleaner inlet and ducting in order to ensure that the passageway is not blocked or collapsed.
  3. Check for dirt tracks on the clean side of the engine air cleaner element, the air inlet hose, and the clamps. If dirt tracks are observed, contaminants are flowing past the engine air cleaner element, the seal for the air cleaner, and/or the air inlet hose.
  4. Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element.
  5. Use the differential pressure gauge of the 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator .


Illustration 2 g01176673
Air inlet system (typical example)

(1) Turbocharger

(2) Air Inlet Piping

(3) Test location

(4) Air cleaner

Connect the vacuum port of the differential pressure gauge to the test location (3). Test location (3) can be located anywhere along air inlet piping (2) after engine air cleaner (4) but before turbocharger (1) .
The air flow through a new engine air cleaner element must not have a system restriction of more than the following amount:

Maximum restriction … 3.7 kPa (15 inch of H2O)
The air flow through a used engine air cleaner may have an additional 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 inch of H2O)

Posted in C18

Leave a Reply

Your email address will not be published. Required fields are marked *