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Well back again

Discussion in 'Lounge' started by Waystro, Sep 4, 2019.

  1. Waystro

    Waystro No Class

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    so this gets more traffic than the Chevy section and you guys are awesome other forums not so much. Now on to my issue
    My 98 Chevy Tahoe 350 vortec threw a code for the injectors I being stupid went to the salvage yard and picked up a spider system well got them in decided I would reuse the intake manifold gasket got it all put back together and it is running like crap rough idle and when I press the throttle it stumbles and shakes and acts like it’s going to die. Is smoking white but not very much at all. When I took the intake manifold off I accidentally got coolant in the intake well I got as much out as I could then check oil I saw no water on dip stick so I fired it up. Let it run for a minute checked out and saw a little water so I drained the oil refilled then flushed again I see no water in oil and coolant is clean. Now it’s hissing from the intake somewhere. And I can see coolant dripping down transmission bell housing but can’t find the leak. I think I read somewhere that a damaged gasket could cause this? Oh pulled intake back off and there is coolant not a lot but it’s in the valley did I just blow my engine are is there hope?
     
  2. chillman88

    chillman88 Supporting Member Supporting Member

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    Which gasket did you reuse? Upper intake gasket is basically an o-ring. The lower intake gaskets have long been a problem on these engines.

    If the oil looked ok after you changed it and before you pulled the intake again I wouldn't write it off yet. I replaced the intake gaskets on a 454 that was BAD and it's running fine after the fact.

    Get a good set of new lower intake gaskets, put a VERY THIN smear of black RTV around the coolant passages on both the intake and head.

    When you put it back together oil up all the o-ring seals good. ESPECIALLY that oval one that the injector plug goes through in the top of the upper intake, that one can be a real bugger to seat if your not careful.
     
  3. Waystro

    Waystro No Class

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    The top one( o ring) I didn’t touch the lower as I was only doing injectors. When I took the manifold back off last night the oval o ring around the injector housing was sitting in the valley it was broke wonder if that was the hissing I heard.
     
  4. chillman88

    chillman88 Supporting Member Supporting Member

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    If you didn't mess with the lower gasket you shouldn't have been into the coolant. There are no coolant passages in the upper intake manifold??
     
  5. Waystro

    Waystro No Class

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    Hmm I wonder what’s going on then because I definitely have coolant in my intake valley not a lot but still and then some leaking down bell housing. Weird how right after I did injectors it started acting up
     
  6. chillman88

    chillman88 Supporting Member Supporting Member

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    Coolant goes through the lower intake but shouldn't be in the upper.

    I'd be looking REALLY closely to find out where it's coming from. I wouldn't be surprised if lower intake gaskets are leaking and somehow causing the problem but I'd try to figure out where it is coming from before going that far.

    I have one pulled apart in the garage if you need any pictures just let me know.
     
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  7. Waystro

    Waystro No Class

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    That would be awesome!!
     
  8. typ4

    typ4 Supporting Member Supporting Member

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    Just yank the lower intake and replace the gaskets, its not a if thing , its when, I just did the second vortec at work 2 weeks ago, 2 hours if you air tool it. But then ive done half a dozen or so.

    I mostly hauled ass on it to prove a point to my coworker that hand jives everything small.
    He has never worked flat rate.
     
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  9. Waystro

    Waystro No Class

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    So last night made some progress getting accessories off and wiring moved out of the way. Front is definitely leaking and the rtv is oozing out of the front:shocked:
    Got dark so figured I’d resume in the am but damn rain.
     
  10. chillman88

    chillman88 Supporting Member Supporting Member

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    Oh yeah, I know how that goes...

    Make sure you inspect around the coolant passages closely. Sometimes there's pitting which is why I said to LIGHTLY smear some RTV around those ports.

    Are you running Green coolant or Orange DexCool?
     
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  11. Waystro

    Waystro No Class

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    I’m running green first thing I do with Chevys is get that Dex Cool out. Should I rtv around the gaskets for added sealing?
     
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  12. chillman88

    chillman88 Supporting Member Supporting Member

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    I would do it around the coolant passages only, and only if there is corrosion that has compromised the mating surfaces.

    If the mating surfaces are good and smooth I would just use GOOD gaskets, like the fel-pro ones with the metal ring so they're more resistant to being over-torqued.

    PERSONALLY I would buy this set https://www.summitracing.com/parts/FEL-MS98000T/

    but I would buy them from RockAuto. $48 plus shipping.
     
  13. Waystro

    Waystro No Class

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    8C3BEFDA-23EE-40F3-ADD1-CEA63BA1FE01.jpeg 8A90786F-0DC1-4B09-96A3-53F8FFCF0599.jpeg So this is my valley any thoughts on why it’s this sludges up? And is it new engine time?
     
  14. DaveBen

    DaveBen Supporting Member Supporting Member

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    Oil not getting changed every 5,000 miles, or so..., would cause sludge build up. That is over time and not just one or two oil changes. Poor maintenance.
     
  15. chillman88

    chillman88 Supporting Member Supporting Member

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    Wow... I've never seen anything that bad!

    Clean it up as best as you can and run some decent synthetic oil for a while to work on cleaning it up the rest of the way.
     

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