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Volvo Penta 7.4gl 1995 Water in Oil

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  • Volvo Penta 7.4gl 1995 Water in Oil

    Hey guys,

    Looking for some pointers here.

    I have a 1995 Volvo Penta 7.4GL (454) raw water cooled engine that has experienced oil in the water. Have been running the engine off a hose, and noticed the oil to be a white milkshake. Ran the engine a little hot, white steam came out of the exhaust, and the color of the oil darkened. I gave it an oil change thinking it was some condensation left over since it has been sitting for a while, but the water milkshake returned.

    I started thinking leaking exhaust manifold/risers, but when I took those off and tested them with water, nothing leaked back into the exhaust ports.

    I started thinking that it was a blown head gasket and began taking the engine apart. On first glance the gaskets for the intake manifold were really bad, and crunchy. I thought maybe this could be the reason for the leaking but I figured I'd just replace the head gaskets since im taking the engine apart. I then discovered the intake manifold had a hole in it, starboard side on the middle port (I think its air intake from the carb?). I bought a new iron intake manifold to fix this issue.

    I then started taking off the heads, checked the valve for leaks by filling the intake and exhaust ports with water and waiting for some leaks. A couple of them did have some leaks (probably some bad compression going on), so I did a valve refresh with some valve grinding compound, checked for leaks and all is good.

    The head gaskets seem to be in good condition, they're not corroded or cracked. I did notice some slight surface rust on a couple of the cylinder walls. Could that be indicative of water in the cylinder?

    Anything else I should be looking for before putting everything back together? I'm in San Diego, CA, so no temperatures below freezing. Boat has been stored on a trailer. I would hope that the block is not cracked. Any tips or advice on what I can do would be greatly appreciated.

    Thank you

  • #2
    Using water to find leaks is not a good method, using acetone would be better. Water is thick and needs a larger opening to pass

    The exhaust mans should use air pressure or acetone, just don't have plastic and rubber parts from making contact

    Water in cylinders is a leak from a gasket or engine part (intake, exhaust mans, head or intake gasket)
    94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
    95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
    07 Seadoo GTX
    Merc Adults Only VP Adults Only
    G-Dad always said "First Liar doesn't stand a chance"

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    • #3
      post a pic of the manifolds. however if you suspect them, simply change them and the riser. especially if the boat ever saw salt water

      agree with AD, use acetone to check for leaks
      Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

      1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

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      What’s behind you doesn’t matter.Enzo Ferrari

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      • #4
        to iBoats . . .

        You did not mention the gasket between the manifold and the risers . . . usually the first thing to leak.

        Usually, when water is found in the oil, a cooling system pressure test is in order to locate the source of the leak. Taking the engine apart pre-maturely defeats that, as you will be mostly guessing as to the actual cause (as you were doing).

        Tell us (post a picture) of the 'hole' in the intake manifold . . .

        Also tell us a bit of history on the boat/engine. More info is better than less.
        Best regards, Ted . . . . Cape Cod, MA

        Current Boats: Formula 330 Sun Sport, O'Day Mariner Sail #3224, Sunfish
        Past Boats: Catalina 22 Sail #10531, Formula 242 Sun Sport
        Twin Mercruiser 7.4 LX MPI (0F802036, 039), Bravo 3's (0F806198, 199), Mercury 7.5 HP (1969), Johnson 4.5 HP (1980)

        My Boating Web Pages: http://www.tpenfield.com

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        • #5
          https://www.crowleymarine.com/johnso...arts/53969.cfm
          http://www.volvopentastore.com/Lubri...view_id.778967



          I think some of these engines had an engine oil cooler, here is a pic of the OMC version, which is identical to the Volvo you have (I used the OMC parts catalog because if you don't know the Volvo model # their catalog is hard to navigate, but here it is, same part same part number NLA from OMC but Volvo still lists it as available) if this cooler leaks it will put raw water into the motor oil and would have been the first thing I checked!
          Next, exhaust, then intake manifold and cyl heads.
          After the oil cooler.....
          If you had water in the oil and the cyls, yes it could be the exhaust esp the elbow gaskets...
          If you have water in the oil but not in the cyls, the exhaust is not a likely culprit, possible though...
          Other causes are a leaky intake gasket, this will put water in the cam valley, and head gaskets these will put water in the motor oil or in the cyls or both, depending on how they are blown. Other more expensive causes are a cracked head, block or a rotted intake manifold.
          Before taking it part I agree there are cooling system pressure tests that would reveal leakage, I also rigged up a dynamic test on my old engine to see if combustion gases were getting in the cooling water and sure enough they were. I had water in a cyl and water in the oil and the exhaust passed the acetone test.
          I wound up having the heads checked at a machine shop and the outcome was that exhaust valve seats were cracked on both heads in the center cyls (prob from an overheat 3 years before the head gaskets finally blew). The water in the cyl and oil was clearly from the blown HGs.
          The cure was installing a set of re-man heads with Fel/Pro head gaskets and new ARP head and manifold bolts.

          In your case I might get the heads checked out by a good machine shop and re-assemble with a Fel/Pro top end Marine gasket set, you may want to replace the head bolts depending on what condition they are in.

          If you are in salt water, you may need to get a set of re-man heads because those could be close to rotting through, behind the exhaust valve seats, have the machine shop check that carefully if it was used in salt all that time. On my heads the cooling passages were eroded from salt use and even if they were not cracked, the machine shop felt that they would not seal right after being re-surfaced so for that reason and the cracks, I replaced with re-man heads.
          If used in fresh water you may just need a basic freshening up of the heads.

          If the exhaust looks good (only if used in fresh water if in salt they need to be changed every 5-7 years) it can be acetone tested and for sure if you have an engine oil cooler, get it tested!
          Last edited by Lou C; December 24th, 2019, 11:20 AM.
          1988 Four Winns 200 Horizon
          4.3 OMC Cobra

          98 Jeep Grand Cherokee 4.0 Selectrac
          07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

          "While air doesn't freeze....rust never sleeps"

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          • #6
            Hey guys,

            Thank you for the great tips. Ill make sure to give the acetone test a try with what I've done so far. To go off of what Lou was saying, I did check out the oil engine cooler (with pressurized water, around 20 psi), maybe I should go back and try with acetone. I'll make sure to report back with photos of the intake manifold hole, alongside photos of the exhaust manifolds and elbows.

            As far as info on the boat and engine, I bought it as a fixer upper for almost free. Its a 28ft Larson 1995 with a 7.4GL Volvo Penta 454. It was running when I purchased it. No water in oil at time of purchase. As far as what I've seen, the engine has about 780 hours (according to hour meter, seems to be original factory Faria gauge, but I don't know if it was switched out). The boat spent some time in the ocean, has bottom paint on it, but other than that it has spent many years in storage on a trailer.

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            • #7
              I don't think I'd run acetone thru the oil cooler, if it does not leak at 20 psi its probably fine because there is very little pressure in a raw water cooled cooling system.
              So it was used in salt water, has your use continued that? If so then really get the cyl heads checked out, and check the mating surfaces of the cyl heads where the intake mates to them, in the front at the the water passages. I think the Fel/Pro marine gaskets are superior to the OE gaskets. Acetone test is good for the exhaust manifolds. I used to change mine every 5-7 years and never had water in the engine from the exhaust and this boat was in 100% salt water on a salt water mooring, 6 months out of the year for 15 years. The hole in the intake, was that in the center exhaust cross over passage? These and the small block Chevrolets used an exhaust cross over to heat the spring for the auto choke and also to keep the carb from icing in cold damp weather. This was done away with when they converted to Vortec heads, so the intakes are totally different from pre-vortec (what I have and you have likely) and Vortec. However water from an intake will usually be from a hole rotted right under the thermostat housing, or leaky intake gaskets at the front water transfer ports that let hot water out of the cyl heads and out through the thermostat housing.

              post up some pix we love pix!
              1988 Four Winns 200 Horizon
              4.3 OMC Cobra

              98 Jeep Grand Cherokee 4.0 Selectrac
              07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

              "While air doesn't freeze....rust never sleeps"

              Comment


              • #8
                some pix from my top end overhaul....
                1988 Four Winns 200 Horizon
                4.3 OMC Cobra

                98 Jeep Grand Cherokee 4.0 Selectrac
                07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                "While air doesn't freeze....rust never sleeps"

                Comment


                • #9
                  Alright, here are some pics of the intake manifold hole. Pretty big. I went ahead and bought a new one.

                  Also attached are the condition of the intake gaskets, head gaskets. The intake ones look a little rough.

                  ​​​​

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                  • #10
                    Here is the condition of the heads when I opened them up (very rusty!), also with my little leak test with water (which I will repeat with acetone). I have cleaned up the carbon off the valves, and will get to cleaning the carbon off the cylinder heads too.

                    I'll be posting the exhaust manifold elbows later.

                    Comment


                    • #11
                      Does look like it was the intake and gasket

                      check out the oil engine cooler (with pressurized water, around 20 psi
                      Its not the oil cooler, the oil pressure is at least 10 psi idle and 40 psi running. Water pressure is a 5 psi idle and 30 psi running. If oil cooler had a leak the oil would be pushed out into the exhaust water and would run dry

                      To test an oil cooler I would use air at 60 psi on the oil side
                      94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                      95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                      07 Seadoo GTX
                      Merc Adults Only VP Adults Only
                      G-Dad always said "First Liar doesn't stand a chance"

                      Comment


                      • #12
                        That hole is not in a water passage but the intake gaskets look very suspicious and could be your source of water, did you have water only in the oil and not in the cyls? Were any of the fire rings for the head gasket burned through? It will look like a slit on the side and can let water in a cyl and in the oil...
                        1988 Four Winns 200 Horizon
                        4.3 OMC Cobra

                        98 Jeep Grand Cherokee 4.0 Selectrac
                        07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                        "While air doesn't freeze....rust never sleeps"

                        Comment


                        • #13
                          It does look like you had some water in one of the cyls, not a lot but some in the one on the left hand side of that pic, is it the rear cyl #8? It will be interesting to see what your manifolds and elbows look like. That hole in the intake is curious. I'm not familiar with the big block only having had the small block V6 but it makes me wonder how it rusted/burned through there....
                          I am still running the 32 year old one on mine, and at least half that time it has been in salt water....

                          Also compared to how my engine looked yours appears to have more rust in the cam valley area, which would suggest the intake gaskets were leaking, but once water gets in the oil it tends to spread around and you can find evidence of it in areas far from the source. I was surprised that I had very little corrosion anywhere really even though it was salt water, for approx. a week or so, till I figured out what was happening and drained it after every time I ran it.
                          Last edited by Lou C; December 24th, 2019, 04:05 PM.
                          1988 Four Winns 200 Horizon
                          4.3 OMC Cobra

                          98 Jeep Grand Cherokee 4.0 Selectrac
                          07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                          "While air doesn't freeze....rust never sleeps"

                          Comment


                          • #14
                            Thank you for the responses guys, really appreciate it.

                            Attached I have the exhaust manifolds and the elbows. The gaskets ripped up as soon as I took the elbows off. I haven't cleaned then up properly yet. There's definitely some rust inside the water jackets, but I still need to confirm with acetone if they are the source of the leaking.

                            And Lou that is cylinder 8, there wasn't any water inside when I opened it, but there is some rust there. Gotta pop off the starboard side and check those cylinders.
                            ​​​​​

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                            • #15
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                              They don't look bad but you really can't tell till the sealing surfaces are cleaned up and you test the manifolds with acetone. If they are good you could re-use them but install new elbows and gaskets.
                              1988 Four Winns 200 Horizon
                              4.3 OMC Cobra

                              98 Jeep Grand Cherokee 4.0 Selectrac
                              07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                              "While air doesn't freeze....rust never sleeps"

                              Comment

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