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what leak is this??

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by 9191gmc, Jul 4, 2009.

  1. 9191gmc

    9191gmc Rockstar

    What leak does this look like to you.? The engine oil plug is dry, the trans pan is clean and dry, this looks like where the bell meets the back of the engine,no?
    If this looks like a leaky rear main seal, can you change that seal without pulling the engine..?? thanks....look at pics....2001 silv V6

    Attached Files:

    Last edited: Jul 5, 2009
  2. Z71_guy

    Z71_guy Epic Member 5+ Years 1000 Posts

    depends how far up can you see oil, could be a rear main but it could also be oil sending unit valve cover gasket under the intake there is a metal cover that can leak
  3. Mean_Green_95

    Mean_Green_95 Epic Member 5+ Years 1000 Posts

    Also, the oil filter mounting plate is built into the oil pan. The gasket there for the oil lines to and from the filter are really thin, and on almost every truck with these motors it leaks. I read an article on it in some magazine at the dentist's office while waiting for a root canal. If the leak goes up that high, that could be the source.
  4. kjb13

    kjb13 Member

    What is the threaded hole for?? I just bought my '97 Silverado and haven't spent any time under it yet, so I'm not real familiar with it yet, but that threaded hole looks out of place.
  5. Mean_Green_95

    Mean_Green_95 Epic Member 5+ Years 1000 Posts

    I think that threaded hole is for if you had a different transmission, like a 4L80E or maybe a 4x4.
  6. hmaster77

    hmaster77 Rockstar

    on the older trucks i have replaced a rear main seal on a 350 without pulling it on 8 an 86 chevy so its prolly possible
  7. ukrkoz

    ukrkoz Rockstar 100 Posts

    get truck on ramps or lift; take 2 cans of carb cleaner, and clean EVERYTHING in that area, all the way up onto the engine block; wipe clean. drive for few days, get back on ramps, and check it out.
    just looking at it, it is either rear main seal, or it is coming from the pass side block or oil pan gasket. look to the right of the right arrow you have on your pic - there's oil streak coming DOWN from somewhere.
    then let us know. i think, you really need take a good look at the pass side pan and block.
  8. L0sts0ul

    L0sts0ul Rockstar 100 Posts

    Rear main seal.

    its a 1 piece seal, and it sucks.

    drop the tranny and good luck.
  9. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    As has already been posted the first step to fixing this is cleaning the area real goodl and locating the source of the leak, theres a couple of places that it can be coming from.
    After you get it cleaned up real good and run the engine to reproduce the leak get under the truck and start looking around, a good flashlight and inspection mirror can assits you a lot here.
    If it's the rear main seal your probably better off pulling the engine, I've done one from the bottom and wont do it that way again.
    For the oil pan gasket I'd also recommend pulling the engine.
    Almost anything else can be done with the engine in the truck.

    The threaded hole is for a different eng/trans configuration, if you look around you'll find many unused bolt holes for different engine/trans/t-case configurations under your truck.
  10. 9191gmc

    9191gmc Rockstar

    If I had your average Chevy mechanic,NO dealers, what would it cost me to replace the rear main seal with the newest type that wil fit on this..?? what about if I had them replace all the seals in the area except tran pan..thats new and ok.. $ ??

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