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85 K10 305 Exhaust manifold question for Chevy Guru

Discussion in 'Chevy Trucks' started by POWERBAND, Feb 28, 2003.


    POWERBAND Member
    Messages: 70

    I got an 85 K10 305 std. shortbed with a 7.5 Western Plow setup last fall and after replacing brake lines,PS pump,and much of the electical system I was satisfied it was reliable enough. Last week the exhaust developed a major leak at the Y pipe to manifold connection on the Lft(driver) side and it looks odd. The right side has the cast heat riser/vacuum actutator setup but the left side with the leak appears to have an extension piece or long gasket sleeve (@2") between the manifold outlet and the Y pipe 3bolt flange.
    Anyone know what the heck I'm seeing there, the piece is blown out and I need to know if I'll need to replace the Y pipe which is solid or is there really an odd OEM part in there I should replace. I know the 85/86 SB trucks were all weird as far as main seals and emission shxt applications. The manifolds are the single air injection bung at front and I believe it is all OEM. My usually all-knowing NAPA guy said he never saw this and my 80 Suburban 305/std doesn't have it.
    TIA - Rich
  2. wyldman

    wyldman Member
    Messages: 3,265

    Most had a round donut cast as part of the manifold that the y-pipe seals on.Some had a replacable donut that goes in between the manifold and y-pipe.Once you get the pipe off you will be able to see what type it is.If there is a round piece sticking out from the manifold,that would go into the pipe,then you don't need the donut gasket.The donut gaskets are available at most parts houses.It is possible that the studs let go,or the nuts rotted off and the pipe just dropped down a few inches ?

    If the flare,or "lip" on the y-pipe is rotted off you may have to replace it as well.You will most likely need new studs and nuts as well.If the studs and nuts need to be replaced,and your doing it yourself,it's probably best to just pull the whole manifold,and do them on the bench,much easier than in the truck.