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Front main seal

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BowtieBlazer, May 13, 2003.

  1. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    What kind of beast are we dealing with here? I have a oil leak down the front of the oil pan, hard to say with all accessories intact if its the front main or oil pan, rear main is doing fine, kinda strange the front would start to leak, rare for me to see oil leakage there. What causes the frotn seal to wear down, this isnt a high mileage engine engine is a 350 330HP crate with about 55,000 miles.... If I do tear into it that far I may as well do front rear mains and oil pan gasket correct? /forums/images/graemlins/ears.gif
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Since that's a 1 piece rear main, you'll have to either pull the engine or tranny to get to the rear main. I'd leave it alone.

    The front oil seal is in the timing cover. That one doesn't leak too often. You're going to have to loosen the oil pan at least, if not remove it, to get the timing cover off.

    The front of the pan leaks quite often at the corners where the timing cover meets it if silicone isn't used.

    I'd replace the timing cover gasket and seal, and use the 1 piece oil pan gasket with just a little bit of silicone at the corners and call it done.

    Probably a couple hour job, no biggie.
     
  3. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    did the motor come with a harmonic balancer, or did you use an old one. i replaced that seal when i did a timing chain, but it still leaked from the front of the motor. about 6000 miles later i pulled the motor to do a rebuild in it and i seen a grove in the balancer from the seal. you could have the same thing if you used your old balancer. /forums/images/graemlins/confused.gif not sure if the crate motors came with a balancer /forums/images/graemlins/confused.gif
     
  4. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    this was a new not rebuilt motor and had a new balancer

    I guess I will really have to look around under there and see what exactly is going on, its running oil straight down the center front of the oil pan, so I have a feeling its not the corners of teh pan gasket leaking.
     
  5. TexasT

    TexasT Registered Member

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    To clarify this does not apply to your engine if it went 55K.

    The genius who assembled the engine I am currently overhauling didn't realize that the front two bolt on the oil pan that thread into the timing cover are smaller than the rest and put two of the larger ones into the holes therby bending the timing cover. Fortunately this particular individual was a firm believer in plenty of form a gasket and the two smaller bolts were used along the pan were held in by the formagasket. You could tell the pan had come off because there was the formagasket all over the front main inside the pan. Such diligence probably led to the overhaul in the first place. just an FYI for the DIYer.

    Sounds like the seal just went bad. It happens.

    Rich
     

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