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<H1>Information on Servicing Fuel Injectors to Avoid Contamination #03-06-04-036 - (07/31/2003)</H1>Information on Servicing Fuel Injectors to Avoid Contamination

2001-2004 Chevrolet Silverado

2003-2004 Chevrolet Kodiak C4500/C5500

2001-2004 GMC Sierra

2003-2004 GMC TopKick C4500/C5500

with 6.6L Duramax Diesel Engine (VIN 1 - RPO LB7)

Fuel injectors may become contaminated during engine servicing. Debris between the injector line and the injector line nut may fall into the injector fuel inlet upon removal. Following the procedures below when servicing fuel injectors/lines should resolve this concern.<A name=ss1-1363028><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1363028&evc=numSrch#ss1-1363028" target="_blank">
<H5>Removal of Fuel Injector Lines</A></H5>

  1. <LI =1>Before removing the fuel injector line, use compressed air to blow any debris from between the fuel injector line and the fittings (1,2). Wipe the fittings (1) clean of debris.
    <LI =1>Spray lithium grease, P/N 12346293 (in Canada, P/N 992723), or equivalent, between the fuel injector line and fittings (1,2) to assist in containing any debris during removal.
    <LI =1>Remove the fuel injector line.
    <LI =1>Remove the upper valve cover.
    <LI =1>Remove the lower valve cover.

    <LI =1>Immediately after removal of the lower valve cover, use a vacuum source to remove any contamination in the fuel injector inlet (1). </LI>


After the fuel line is removed and the fuel injector inlet is exposed, DO NOT use compressed air to clean debris. Using compressed air can allow debris to enter the fuel injector inlet and damage the fuel injector.

<A name=ss2-1363028><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1363028&evc=numSrch#ss2-1363028" target="_blank">
<H5>Fuel Injector Cleaning and Inspection</A></H5>

  1. <LI =1>Use a soft bristle non-metallic brush and top engine cleaner, P/N 1052626 (in Canada, P/N 993026), or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before reinstallation.


    The fuel injector must be cleaned with the proper cleaning equipment. DO NOT use abrasive cleaning methods such as a metallic brush to remove deposits. Cleaning an injector with improper tools may damage the fuel injector.

    <LI =1>Inspect the fuel injector nozzle tip (1) for cracks, dents, or other damage.
    <LI =1>Inspect the nozzle tip (1) for any signs of discoloration (dark yellow, tan, or blue) due to excessive heat.
    <LI =1>Replace the injector if any damage is found.
    <IMG id='chkImg1' name='chkImg2' height=296 alt="object Number: 1336212 Size: SH" src=

2020 Chevy 2500HD LTZ Z71
644 Posts

6,539 Posts

Guess what? I will guarantee all eight of those lines need to be replaced when the injectors are serviced.

Every one of mine looked like this....

Edited by: hoot
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