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Front Seal Leak

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  • Front Seal Leak

    1999 210 Maristar

    Indmar LTR VRS 5.7L EFI

    Winterizing the boat today and I was getting all of the fluid out of the block before I filled it back up with antifreeze. A friend was helping me, who knows far more than I do, and thinks I think I have a front seal leak on the block. I just picked this boat up at the end of the season and I knew there was a little bit of oil in the bilge. A local marina thought it was just a sloppy oil change, but there’s just a lot of residue on the front of that engine. When I asked them to look it over they said they couldn’t find any oil leak…

    So assuming it does have a bad seal, how big of a deal is it? As long as I keep tabs on my oil level, is it something that I have to address if it’s just a slow leak? And does anyone have any idea what it would run to fix it? My gut feeling is that this would be out of my scope of ability to fix myself.

    Sent from my iPhone using Tapatalk

  • #2
    Depends entirely on how slow a leak it is. It will certainly make a mess and being petroleum based, having a lot of oil in the bilge is never a good idea. But it is likely manageble for a while with oil absorbing bilge pads and such.

    I presume you actually mean the *rear* main engine seal. The engine is in the boat backwards and the rear of the engine is facing forward and attaches to the transmission (the Maristar is a v-drive). Repairing the rear seal requires removing the transmission and flywheel. I have pulled my transmission to replace the front transmission seal and it is not a hard job, just time consuming. This is a good thread on what is required -

    While I have never seen the actual rear engine seal (I did not need to remove the flywheel when I replaced my trans seal), I imagine it would be something like this -

    If it was the front seal, that would be a whole lot easier since it is actually at the rear of the boat and fairly easy to access.


    • #3
      Thank you for the response, this is actually at the rear of the boat where the you have the exhaust, belt, pulleys etc

      My friend mentioned that I would have to remove the exhaust and probably the pulleys as well.

      If I decide to tackle this, I have no doubt everyone will be able to help me pinpoint the problem as I take it apart, just wondering if there’s a logical progression to do it to see where the problem truly is. And I’m certainly not too proud to be told this is probably out of my league, and I need to let a professional do it before I create more problems...

      I would always rather do something myself versus paying someone, but I also recognize there are limits to my skill set when I have no training or working knowledge of what I’m looking at.

      Sent from my iPhone using Tapatalk


      • #4
        Yeah, so much for presuming. After reading my response, seems pretty silly of me. Sorry about that.


        • #5
          I'd start by trying to narrow down where the oil is coming from. How high on the block is the residue? If anywhere up above the crank, it is possible you have a valve cover leak, which would be way easier.

          If it is the front seal, you would have to pull the harmonic balancer, timing chain cover, and timing chain, to get to the seal. I don't know how hard this is to do in a boat. These get fixed in cars / trucks without pulling the engine, but you have access from below.

          Could also be an oil pan leak near the front of the engine.

          You'll probably need to get in there and clean up all the old oil and then start watching to see where it re-appears.


          • #6
            Found a prior post that might help you out: