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Oil in bilge, not in crankcase!-gctid382666

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    Oil in bilge, not in crankcase!-gctid382666

    After a few test runs of 10 to 30 minutes at the dock, I took the boat out last Sunday for a shakedown. Ran it about 30 miles, at different speeds, keeping an eye on the gauges all the time. Temp, oil pressure, everything OK. Total engine hours were about 2, although I was out for about 3 hours (one hour on a mooring for lunch.) Checked the engine compartment (I think) and put everything to bed.

    Checked the engine compartment again last night. The bilge is full of oil, and the dipstick is dry!

    I wouldn't swear that it wasn't there when I put the boat away, but I do know that the temp and oil pressure gauges didn't move the whole trip Sunday.

    The light was fading and I didn't have a mirror last night, so I'm off to check it now.

    I did have time to run my hands under the parts of the engine I could reach, and nothing came up oily. There are no stains in the bilge, just a pool of oil in the exact center of it. No signs of oil spurting or even dripping from anything.

    It's a 2003 285 with a Merc 350 Mag MPI. It has a remote oil filter and a hose in the oil drain plug that allows you to suck the oil out without getting under the engine. My first suspicion is the drain hose, since it's one thing I can't see at all that's in the exact center of the engine.

    Any suggestions?

    Also, lesson learned, NEVER skip the step of checking the engine compartment. I don't know what happened, but if it had happened while I was at the mooring 7 miles offshore, instead of when I got back, this story would have ended very differently!

    We could have a lot of suggestions but in a case like this, there is nothing better than a head in the bilge visual.

    Most likely you are correct about the drain. Anything else most likely would be under pressure and it would be all over the bilge.

    A rusty pan could be it also.

    Started boating 1955
    Number of boats owned 32
    3870 presently owned
    Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner


      Update: Even with the new 36" extension mirror w/light that I bought, I STILL can't see everything.

      I can see the fitting where the drain hose attaches. The rest of the oil pan looks good, almost like new. But the fitting has rust, and appears to be weeping oil around the weld. It's cold now (54 degree water temp, so the bilge area is about that) so it's not leaking much. Probably when it was hot it was dripping a lot faster.

      The mechanic here promised he'd look at it, but assuming I'm right, he can't work on it for a couple of weeks. No way I'm pulling the engine myself, so I'm shore-bound for a while.

      Anybody remember the thread where someone recommended a good bilge paint? If the engine has to come out anyway, I'll try to get that done at the same time.

      Any other jobs that would be good to include? I'm thinking of replacing the sea water hoses under the engine, I never liked the way the dealer installed the closed cooling system anyway, the intake hose from the outdrive has too tight a bend and it's flattening out.

      I'll also put in a larger bilge pump, and maybe add a small tube down to the lowest point that I can use to remove every last drop of water after a rain. That should also help keep the bottom of the oil pan dry.


        CaptTom wrote:
        Anybody remember the thread where someone recommended a good bilge paint?
        Yep... it's called Bilgekote.



          If the engine needs to come out of the boat, it's also a good time to add a larger bilge pump, remote oil filter...


            Thanks, BilgeKote was the one I was thinking of.

            I got to thinking I'd also want to take a good look at the starter, maybe this would be a good time to replace it. Obviously a raw water impeller would be a good thing to swap out, probably spark plugs too while they're easy to see.


              The reason that you're not seeing any oil leaking now is that your pan is most likely empty! Once you're off of the dipstick, there's not a whole lot of oil left in there. Why not add a quart and check again. If there's still nothing showing, add another. By now you should be seeing some indication of where the oil leak is. Hopefully this leaked out after you were shut down. You will have a low oil alarm on that motor, so it should have sounded after you were down a couple of quarts, and as that is not the case, you most likely didn't do any serious engine damage.
              Bob Hawes.
              Kelowna, B.C.
              1998 Trophy 2052 WA
              4.3 Vortec, A1 G2


                Yes, the oil pan was empty. I put the oil-change pump on the remote drain hose and only air came out.

                With the inspection mirror, I can see that there's a rusted area weeping oil just around the fitting where that hose attaches.

                It took me the better part of 2 days, but I got almost all the oil out of the bilge. Some ran forward through the limber hole so I've put in a couple of oil-absorbing diapers to get any that might still come back. Now at least if the pumps come on I won't be slapped with an oil pollution fine.

                I'm officially a "dock molly" until I can schedule the engine pull. Won't be at least until after the holiday

                Oh, and since it was a shakedown cruise, I did monitor oil pressure & engine temperature the whole run. Also, just the exact center of the bilge was fouled. If it had leaked before I returned, it would have splashed everywhere. So I'm pretty sure the leak started after, or at least didn't amount to much until, I returned.