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2003 Sierra Heads

Discussion in 'GM Powertrain' started by rileyjr16, Mar 10, 2014.

  1. rileyjr16

    rileyjr16 New Member

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    Sorry about the hiatus lately guys. Been working 12+ hours a day on the dang ship and dealing with a new addition to the family and the wife. Now before anyone thinks we had a kid, no its a purebred Golden Retriever. I'll put pics up in the coffee shop.

    But for my question, I found a pair of heads that supposedly came from a running engine from a 2003 Sierra 5.3 for 85$ for both of the pair. I know my engine is getting old and is starting a case of the early morning/cold weather knock. Would heads from a 2003 5.3 fit a 99 5.3 engine?

    Is it worth buying and swapping them out at all?
    #1
  2. RayVoy

    RayVoy Active Member

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    Not sure what new heads would buy you, the knock is probably probably cold piston slap, or lifters that have bleed down over night. Both are in the block.
    #2
  3. 00chevy53

    00chevy53 New Member

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    the heads will fit but like rayvoy said probably wont do much..
    #3
  4. Pikey

    Pikey Moderator

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    i would not bother. Plus, before I installed the used heads I would have them checked to make sure that they are not warped or cracked. Then I would have them rebuilt with new valves and valve seats, maybe even a 3 angle valve job. No point in changing something that is working with possibly the exact same part that may not work. I would at least go for an upgrade. if you do buy them make sure they are not the castec heads with the 706 stamp. here is how to identify them. http://ww2.justanswer.com/uploads/Bluegorilla/2008-12-05_142924_Coolant_loss_5.3.pdf
    #4
  5. zuki82

    zuki82 New Member

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    what pikey said!!! If you do get them, at least get them upgraded first! Angle grind, valves, shaved,,,,,
    #5
  6. rileyjr16

    rileyjr16 New Member

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    Well wound up not getting them. I need to behave with my money for right now. If I do anything in the future, it may just be a partial rebuild of the bottom end, all cleaned out and such. But I'm not even sure if that would happen before the truck goes kaboom. Got 259,824 on her now as I am looking at it. Would love to go to 300,000 before I start heavily thinking about new truck time. Gotta pay off this dang dog first.
    #6
  7. RayVoy

    RayVoy Active Member

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    My '09 has cold morning piston slap (it would go away after 30 seconds). I have always used synthetic oil; but a little while ago (maybe 2 oil changes) I started to use Royal Purple, the cold morning slap has disappeared.

    Was it the RP oil, I don't know; but it is gone.

    Maybe an oil change (as in type and brand) might help.
    #7
  8. rileyjr16

    rileyjr16 New Member

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    Think that might be my problem. Always ran Mobil1 5w-30 through it. Change to Valvoline for one change and changed weights for winter. Actually my thing just came on so Saturday, I'm gonna jack her up and change her.
    #8
  9. RayVoy

    RayVoy Active Member

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    That's probably your problem, the "weight" should not be changed for the winter. Run the 5-30 all year round.
    #9
  10. rileyjr16

    rileyjr16 New Member

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    Thats when i started hearing it more and more often is after I changed. Now I let y truck warm up before I leave. But with 5w-30 it wouldn't do it every cold morning like it does now and not for as long. Maybe 30 seconds.
    #10

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