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Thread: Head swap problems

  1. #1
    Join Date
    May 2004
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    Damn the luck if it's one it becomes another. I got the heads installed and went to put coolant back in the system and it wouldn't take it. I pulled the bypass lines off the head and it helped to get some coolant up to that point. Now when I start the truck I have no flow at all through the radiator. The head gaskets were put on with the "FRONT" markings to the front of the block with the drivers side gasket turned upside down since that's the only way "FRONT" will be in the front. LOL Any suggestions like maybe a bad water pump or thermostat? Anyone ever ran into a problem like this before?


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  2. #2
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    Nov 2003
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    Denton Texas
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    Bummer, is it raining something again?
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  3. #3
    Join Date
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    Humble/Houston TX
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    straight from ls1how to's head swap instructions

    "Lay the new head gaskets in place. NOTICE how they go on...there is writing inscribed on them pointing to what should be facing front, what should be up, and what is visible. If you get these wrong you will block coolant passages so make sure you do this correctly."

    i think my gaskets said top side and front on them when i was doing it.

    old mod list: H/C/I/N/E/G 408
    new mod list: 5.3, gears/posi, mufler and tune : (

  4. #4
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    These say front only. Talked with GM and they said you turn the drivers side upside down since the gaskets are identical. If you lay them both front up the drivers side ends up in the rear blocking the passages so I know the gaskets are correct and I looked at the passages. The original gaskets that came off had the drivers side upside down.

    Notice the gaskets both in the up front position. If I were to install them this way you would block the passages on the drivers side rear. One has to be flipped upside down. I even tried the old ones out on my spare block.



    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  5. #5
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    Baton Rouge, LA
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    <div class='quotetop'>QUOTE(NITROUS &#064; Jan 4 2007, 05&#58;26 AM) [snapback]78270[/snapback]</div>
    These say front only. Talked with GM and they said you turn the drivers side upside down since the gaskets are identical.[/b]
    What ya waitin&#39; on? That&#39;s the remedy right there. Git &#39;er dun&#33;
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

  6. #6
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    <div class='quotetop'>QUOTE(1BADC10 &#064; Jan 4 2007, 07&#58;00 AM) [snapback]78272[/snapback]</div>
    What ya waitin&#39; on? That&#39;s the remedy right there. Git &#39;er dun&#33;
    [/b]


    ???


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  7. #7
    Join Date
    Oct 2005
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    Baton Rouge, LA
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    <div class='quotetop'>QUOTE(NITROUS &#064; Jan 4 2007, 09&#58;39 AM) [snapback]78297[/snapback]</div>
    ???
    [/b]
    Your block&#39;s like this, right?



    Those gaskets should line up with the imprinted word &#39;front&#39;, with the four rectangular holes positioned toward the top of the motor. Excuse the pic below, I had to rotate one of the gaskets so you&#39;d see my point of gasket placement/positioning.



    Those gaskets should be identical on both sides, as far as the sealing material for the ports & openings. Don&#39;t worry about reading the word front properly, but just have it positioned where the front of the motor is, and those little tabs are toward the front. That&#39;s what they meant about turn the gasket upside down. Notice in the pic below, the guy who sold me my motor also removed the heads to clean & polish, and put the gasket on wrong, thus causing my overheating problems. That is the driver-side head. Note that the tabs are toward the back of the head (right-ward in pic). One design of the 5.3L head gasket shows that only ONE of the coolant passage ports is open on the gasket. The rear-side is not needed b/c my year/model 5.3L does not have a rear passage to flow coolant on the back of the block, hence the closed part of the gasket. See what I&#39;m talking about?



    You look as if you have the right gasket, if you have the ones like the pic I posted. I can&#39;t imagine still having problems with those gaskets b/c the extra provisions for coolant flow are there. Got an update???
    Test-n-Tune (Nov 23, 2008) - 13.65s @ 98mph

  8. #8
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    Great pics&#33; The gaskets are installed with both tabs in the front and the word "FRONT" to the front of the block with the drivers side upside down. I know the gaskets are installed correctly because I verified them upon installation. I haven&#39;t had time to look at the problem but it acts like the systom is air locked but I can&#39;t imagine that either. I&#39;m going to pull the thermostat and drain the coolant to inspect. I&#39;ve been to busy to mess with it but I&#39;ll figure it out. I"ll keep you posted with the results. As far as the pics you posted, I&#39;m sure someone that doesn&#39;t know how to install the gaskets will defininetly benefit from this post.

    I bet you had flow through the radiator even with your gasket backwards huh? I have no flow whatsoever. I bet you could bolt plates to the top of the block and still have some sort of coolant flow because the pump pulls off the block, not the heads. I could be wrong but I doubt it.

    Thanks


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

  9. #9
    Join Date
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    Location
    Denton Texas
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    When you pull the stat, drill an 1/8" hole near the top of it as an air bleed if there isn&#39;t one already. I think I remember Dustin saying something about pulling the upper rad hose off the radiator, pour coolant into the hose until fluid starts coming out of the top of the radiator.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  10. #10
    Join Date
    May 2004
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    2,120
    I&#39;ll give it a try Greg. I haven&#39;t had time to mess with it and it&#39;s driving me CRAZY.............................I&#39;m ready for some dyno pulls as soon as i finger this out.


    97 GMC, 2002 LS6.

    1991 GMC Syclone #1428

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