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Thread: 07 valvetrain knock

  1. #1
    Join Date
    Mar 2007
    Posts
    14

    07 valvetrain knock

    bought an 07 1/2 ton crew cab new body style yesterday. throwing a PO304 Cylinder 4 misfire. horrific knocking noise is coming from the head/valvecover area. the guy i bought it from said the chevy dealer told him it was a lifter bad. any guesses/suggestions. i have searched all over this site and others and not finding much. i will be tearing into it this weekend and just thought i would see if anyone can guess what it is before i open it up. the truck is 4x4 with 125K. still holds 45psi oil pressure at stop sign and does not have any vibration or balance issues
    1979 K30 straight wheel 4X4. 04 6.0 LQ4, 4L80e, NP205, 60 front, 14 bolt Disc Brake rear

  2. #2
    Join Date
    May 2008
    Location
    Crowder, OK
    Posts
    8,005
    Sounds like one of the DOD lifters failed. If you plan on keeping DOD, replace with a DOD lifter. If not, have DOD turned off in the tune and replace with ls7 lifters.

  3. #3
    Join Date
    Mar 2007
    Posts
    14
    replaced it with dod lifter, ran it for 2-3 minutes and ran good and quiet. changed oil and started it back up. ran for another 5 minutes and it did it again. same lifter just as loud. thanks for the reply pl4boy. any suggestions. i live just south of the kc area and i called a shop around here who does ls motor work(mainly car) and they suggested the o-ring on the bottom of the valley cover could be causing a lack of oil pressure. any help would be provided
    1979 K30 straight wheel 4X4. 04 6.0 LQ4, 4L80e, NP205, 60 front, 14 bolt Disc Brake rear

  4. #4
    Join Date
    May 2008
    Location
    Crowder, OK
    Posts
    8,005
    What's the rocker like? How about the pushrod? Bent maybe?

    1969 Chevy RCLB C10 350/TH400 SOLD
    2007 Chevy RCSB 4.8 4x4 LS SOLD
    2008 Chevy RCSB 5.3 4x4 LT SOLD
    2010 Chevy CCSB 6.2 4x4 LT SOLD
    2005 GMC CCLB DRW 6.6 Duramax 4x4 191,000 and counting
    2013 FORD CCSB F350 6.7 Powerstroke 4x4


  5. #5
    Join Date
    Mar 2007
    Posts
    14
    rocker and pushrod both looked good when i had it apart
    1979 K30 straight wheel 4X4. 04 6.0 LQ4, 4L80e, NP205, 60 front, 14 bolt Disc Brake rear

  6. #6
    Join Date
    Feb 2008
    Location
    Kanada
    Posts
    39
    Have you found the problem yet?

  7. #7
    Join Date
    Mar 2007
    Posts
    14
    so i pulled the gasket off the valley cover. it was obviousoly blown out. replaced it with a new one and still rattles. thinkin i have an ioling issue. think just gonna throw a motor in it
    1979 K30 straight wheel 4X4. 04 6.0 LQ4, 4L80e, NP205, 60 front, 14 bolt Disc Brake rear

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