Other maintenance to perform while replacing lower intake manifold gaskets

Discussion in 'Maintenance & Upkeep' started by Chris22, May 10, 2017.

  1. Chris22

    Chris22 New Member

    That's good to hear...in a way, since I already bought the Fel-Pro set that I had heard so much about.
     
  2. Chris22

    Chris22 New Member

    I'm curious about the oil on the rear of the upper manifold that appears to begin at the top and has coated everything below - from the throttle body and back. Of course now would be the time to address it if need be, but I don't have much of a clue as to why there is oil in that area. It gets thick towards the rear on the top of the lower manifold, and below; my hands got covered when working back there. Any ideas?
    The driver side valve cover is quite gunky too. I'm not sure if that is just the result of being sloppy when adding oil or what.
     

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    Last edited: May 13, 2017
  3. Cowboytrukr

    Cowboytrukr Active Member 100 Posts

    If I was to hazard a guess, I'd say it's your valve covers. Since you have everything off you may as well change the valve cover gaskets now and wash it all down.
     
    Chris22 likes this.
  4. Chris22

    Chris22 New Member

    What about the thin oil coating that covers the upper manifold, would/could the oil travel up there? Even the top ledge of the MPFI has a coating on it. I don't know how oil/gunk is getting up there, or coming from somewhere near there.
     

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  5. Differently

    Differently Active Member 100 Posts

    Don't forget to change the oil after. I just bought my truck and found receipts in glove box suggesting the gaskets were replaced. Also found a bunch of water in the oil pan.
     
  6. Cowboytrukr

    Cowboytrukr Active Member 100 Posts

    The amount of air movement inside the engine bay is likely to be the culprit. Brake cleaner and degreaser like Purple Power will clean it up nicely. Did you happen to check to see if you had any oil leaks at the back of the intake?
     
  7. Chris22

    Chris22 New Member

    For sure, lots of little bits of debris fall in when doing this job despite preventive measures.
     
  8. Chris22

    Chris22 New Member

    I'm not sure how to check for an oil leak there other than just looking for oil. I can say that the wire-harness bracket mounting bolt at the rear passenger side of the engine was gooped up pretty good. I don't see much oil accumulation on the back of the manifold, just a good coating. Image 192709 is without a flash for natural view. It seems strange to me that the upper manifold is coated in oil, and that the front passenger side is clear of an oil coating.
     

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  9. Chris22

    Chris22 New Member

    It's a bit concerning that there is oily gunk around the fuel injectors. Is this normal, and should it be cleaned? Not a good pic...
     

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  10. Cowboytrukr

    Cowboytrukr Active Member 100 Posts

    Yes, it should be cleaned. The mess is carbon deposits and probably some oil due to leaking gaskets. I haven't had the blessing of tearing down a Vortec myself. All of what you're seeing should be soaked and cleaned.

    There's the small chance that it's due to leaking valve stem seals.
     

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