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  • Oil leak? Possibly oil pan gasket?

    Hello,

    I've got 1100 hrs on my 1997 LT1 and I am seeing a little oil build up under the engine?

    I don't know where the leak is? Perhaps the oil pan gasket?

    My question is if the leak is coming the the oil pan gasket? Is it possible to change the oil pan gasket without pulling the engine?

  • #2
    I'd first suspect a rear main crank seal. Oil pan gasket is possible but.....

    Find the leak and look backwards. Wipe it clean, place cardboard or paper towel under the pan and see what you come up with.

    Did I mention a rear main? :-)
    93 190
    (safe click)
    John 14:6
    (safe click)

    Comment


    • #3
      The leak does look like it is toward the rear. So I don't know much about engines, but it sounds like a rear main leak is not good? I will clean it up and run it a few more times this year, hopefully I can see exactly where it is leaking? I read that LT1's can leak from the intake gasket as well?

      If it is a rear main seal leak? I would assume the engine would need to be pulled to fix it?

      Originally posted by waterlogged882 View Post
      I'd first suspect a rear main crank seal. Oil pan gasket is possible but.....

      Find the leak and look backwards. Wipe it clean, place cardboard or paper towel under the pan and see what you come up with.

      Did I mention a rear main? :-)

      Comment


      • #4
        if it is a rear main the engine needs to be pulled out enough to change the seal. I'd check the oil pressure sending unit as well, oil filter gasket? So many places to check
        1981 MasterCraft
        19' Skier 351W PowerSlot
        Long gone is the Trans AM waiting for another

        Comment


        • #5
          Okay.. Thanks for the info. It seems to be a prevalent leak, so I should be able to locate it rather easily once I clean it up.

          Originally posted by 1redTA View Post
          if it is a rear main the engine needs to be pulled out enough to change the seal. I'd check the oil pressure sending unit as well, oil filter gasket? So many places to check

          Comment


          • #6
            Before you go to the rear main check stuff up top. The engine is tilted to the rear so everything will end up at the back of the engine. Before going to the bottom, check valve covers and the rear seal on the intake. I have a 1996 PS 190 with a standard 350. You cannot change the pan without lifting the engine. The oil pump and pickup are in the way.

            Comment


            • #7
              One other area that wasn't mentioned is the drain plug. The drain plug is a pretty substantial brass nut that has a drain hose attached to it. It's incredibly close to the bilge of the boat and if you, or the PO ran around with excess water in the bilge constantly the oil pan will rot away around that brass nut. You can get a good look at it with a small mirror.

              Comment


              • #8
                A good winter project, oil pan gasket, rear main seal, also...upgrade to a new heavy duty damper plate for transmission input shaft..Ask me how I know, was a bummer summer project.

                Comment


                • #9
                  I was wondering if it is a rear main seal and the engine must be pulled, is there a list of other things to do while its out? Thanks for the heads up on the damper plate.

                  I hope to be able to clean it up and run it later this week.

                  Originally posted by Fullpass View Post
                  A good winter project, oil pan gasket, rear main seal, also...upgrade to a new heavy duty damper plate for transmission input shaft..Ask me how I know, was a bummer summer project.

                  Comment


                  • #10
                    If that's the goal…to be back in the water as soon as possible, Probably can be done to just pull the transmission…some work still, just to remove transmission/support engine, move drive shaft back and back transmission spline out of damper plate.

                    Would install a "Speedysleeve" 50 bucks over crankshaft for New seal to ride on..almost a must with 1100 hours to fix the leak. Would look at the crankshaft sealing surface, chances are a groove has developed and worn into the crankshaft surface, actually causing the leak..normal and the "Speedysleeve" will fix that.

                    Ah..transmission out/engine supported…removing the damper plate and flywheel..there you are looking at the rear main seal, pry out, clean crankshaft sealing surface, measure crankshaft O.D. with calipers for speedysleeve, install New sleeve & new seal ..done

                    Installing crankshaft & flywheel..I would buy a tap and die set from harbor freight..15 bucks, chase all the crankshaft threads & flywheel damper bolt threads with a tap to remove previous "loctite" The "loctite 271" would be the correct one to use when reinstalling crankshaft flywheel bolts with a torque of 70 or 75 foot pounds..damper plate bolts 35 / 40 pounds and loctite can have Napa get the correct "Loctite" for you usually in a half day..6 bucks ..

                    Make sure

                    Make sure the crankshaft flange and the flywheel contact surface are clean and bare metal no paint in-between when matting the two together and no paint under crankshaft head bolts when installing..Things can loose up if any paint is between these surfaces.

                    Just off the top of my head…what you might be in for…More questions just ask and others can chime N

                    As alway find the correct manual and specs…to do the job…these are just of hand values

                    Comment


                    • #11
                      Originally posted by Bouyhead View Post
                      One other area that wasn't mentioned is the drain plug. The drain plug is a pretty substantial brass nut that has a drain hose attached to it. It's incredibly close to the bilge of the boat and if you, or the PO ran around with excess water in the bilge constantly the oil pan will rot away around that brass nut. You can get a good look at it with a small mirror.
                      I should have mentioned that. Happened to my 1996 but not around the drain hose. It was the back corner of the pan. See attached pic.
                      Attached Files

                      Comment


                      • #12
                        WOW! Thanks for all the info. I got a quote from the dealership and it was $1500.00 bucks.
                        I plan on this Saturday cleaning up the engine and running the boat, hopefully I can confirm where the leak is?

                        Originally posted by Fullpass View Post
                        If that's the goal…to be back in the water as soon as possible, Probably can be done to just pull the transmission…some work still, just to remove transmission/support engine, move drive shaft back and back transmission spline out of damper plate.

                        Would install a "Speedysleeve" 50 bucks over crankshaft for New seal to ride on..almost a must with 1100 hours to fix the leak. Would look at the crankshaft sealing surface, chances are a groove has developed and worn into the crankshaft surface, actually causing the leak..normal and the "Speedysleeve" will fix that.

                        Ah..transmission out/engine supported…removing the damper plate and flywheel..there you are looking at the rear main seal, pry out, clean crankshaft sealing surface, measure crankshaft O.D. with calipers for speedysleeve, install New sleeve & new seal ..done

                        Installing crankshaft & flywheel..I would buy a tap and die set from harbor freight..15 bucks, chase all the crankshaft threads & flywheel damper bolt threads with a tap to remove previous "loctite" The "loctite 271" would be the correct one to use when reinstalling crankshaft flywheel bolts with a torque of 70 or 75 foot pounds..damper plate bolts 35 / 40 pounds and loctite can have Napa get the correct "Loctite" for you usually in a half day..6 bucks ..

                        Make sure

                        Make sure the crankshaft flange and the flywheel contact surface are clean and bare metal no paint in-between when matting the two together and no paint under crankshaft head bolts when installing..Things can loose up if any paint is between these surfaces.

                        Just off the top of my head…what you might be in for…More questions just ask and others can chime N

                        As alway find the correct manual and specs…to do the job…these are just of hand values

                        Comment


                        • #13
                          If it is a leak similar to Blackhawk36, drain the oil. Prep the pan with some 100 grit, remove all paint residue with acetone, apply JB Weld liberally, allow to fully cure. My friend had a Malibu that had extensive rust damage on the pan. It was still leak tight 3 years later.

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                          • #14
                            AZDave is correct on prep. When I cleaned it up there were several other small holes hidden by rust and paint. I ended up welding a 2X2 inch patch on to repair it.

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                            • #15
                              I've read the other possibility of the LT1 leaking oil could be a leak on the intake towards the back. If that is the case, I imagine the engine wouldn't need to be removed? And an intake repair would be a less expensive repair? That may be something I could do myself?

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