MerCruiser 4.3L V6 milkshake oil from cracked intake manifold, how to remove milkshake oil?

[mikeincolo]

I pulled my 2008 Sea Ray 185 Sport with 4.3L V6 MerCruiser our of storage (Colorado), inspected, hooked up hose, started right up, ran to temp, all good with oil pressure, temp, sounded great. Then performed lake test. Let it warm up, then ran at 3000rpm for about a mile or 2... milkshake coming out of valve cover breather hose to spark arrester.

Shut it down, got it home, did compression test: all spark plugs looked good and not wet, compression was 130psi except cylinder #4 was 100psi. Drained oil, let it drain for a couple of days, and got about 3 gallons of milkshake out. Note: thick milkshake drained very slowly, tried manual vacuum pump with at least 500 pumps - and it was just too thick to get pulled up and out.

Removed exhaust risers and manifolds, looked good, removed valve covers, lotsa milkshake but looked good otherwise, removed intake manifold, gaskets looked fine and... it was cracked on the underside, starboard side. I figured I was in this deep so I might as well pull the heads to have them magnafluxed and reman'd. shop reported back that cylinder head on starboard side had a leaky valve which explains the lower compression on cylinder #4.

Waiting on new intake manifold, will reassemble and post again.

Question: Contemplating how I will clean out the milkshake from motor. Spec is 20w-40 NMMA FC-W rated oils, synthetic preferred. Thinking I will rebuild, add oil/filter, run at temp for 30 mins, change oil/filter and run on lake for a few hours, monitor. Maybe use non-synthetic with Marvelous Mystery Oil for the 1st oil cleaning / relubricating process.

Big takeaway - when winterizing remove plug from intake manifold to drain water, in addition to all the blue plugs, etc.

Question: Does anyone have experience and advice for the first run of the motor after reassembling - with the objective of cleaning up the milkshake WITHOUT seizing/breaking anything. That said, any other sage advice?

Thanks in advance, Mike
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[dubs283]

Use whatever solvent you like to clean crankcase. Mineral spirits one quart with 4 30 wt oil qts works. Run sound engine on muffs with new filters and oil changes til not too milky. Then let heat soak burn off the rest of the water

This is of course you've solved the issue of your water contamination, can't rule out a cracked block yet

FYI, I've never seen a merc crack a 4.3 intake manifold unless nothing was drained properly

 

[Lou C]

1) how did you winterize the boat? drain manually and poke all drain holes?
or suck AF up the drive method? If #2 that could explain and might have more things cracked than just the intake
2) I have posted this before, that Volvo & OMC said that the drain in the front of the intake on the vortecs should be removed, but others say no, not needed if the block drains are removed & poked AND the big hose is disconnected on the bottom end, that drains a lot in addition to the block drains.
When I had water in the motor oil from blown HGs the way I got the oil/water mix to pump out, was I used a heat lamp next to the oil pan to heat the oil in the pan up to approx 150* or so.

 

[tank1949]

1) how did you winterize the boat? drain manually and poke all drain holes?
or suck AF up the drive method? If #2 that could explain and might have more things cracked than just the intake
2) I have posted this before, that Volvo & OMC said that the drain in the front of the intake on the vortecs should be removed, but others say no, not needed if the block drains are removed & poked AND the big hose is disconnected on the bottom end, that drains a lot in addition to the block drains.
When I had water in the motor oil from blown HGs the way I got the oil/water mix to pump out, was I used a heat lamp next to the oil pan to heat the oil in the pan up to approx 150* or so.

that's low compression. I believe all should be >150. You have to find water leak. That will determine if block is salvageable or requiring a total rebuild.

 

[dubs283]

1) how did you winterize the boat?

Uh.......

101, Lou

 

[dubs283]

In any case, yeah OP's motor is most likely fubar

 

[mikeincolo]

Use whatever solvent you like to clean crankcase. Mineral spirits one quart with 4 30 wt oil qts works. Run sound engine on muffs with new filters and oil changes til not too milky. Then let heat soak burn off the rest of the water

This is of course you've solved the issue of your water contamination, can't rule out a cracked block yet

FYI, I've never seen a merc crack a 4.3 intake manifold unless nothing was drained properly

In short, winterizing procedure: after fogging the motor, I removed the 5 blue-plugs, poked drain holes with wire, poured a few gallons of RV anti-freeze thru the 1.5" water intake hose, poked with wire again.

 

[mikeincolo]

1) how did you winterize the boat? drain manually and poke all drain holes?
or suck AF up the drive method? If #2 that could explain and might have more things cracked than just the intake
2) I have posted this before, that Volvo & OMC said that the drain in the front of the intake on the vortecs should be removed, but others say no, not needed if the block drains are removed & poked AND the big hose is disconnected on the bottom end, that drains a lot in addition to the block drains.
When I had water in the motor oil from blown HGs the way I got the oil/water mix to pump out, was I used a heat lamp next to the oil pan to heat the oil in the pan up to approx 150* or so.

Use whatever solvent you like to clean crankcase. Mineral spirits one quart with 4 30 wt oil qts works. Run sound engine on muffs with new filters and oil changes til not too milky. Then let heat soak burn off the rest of the water

This is of course you've solved the issue of your water contamination, can't rule out a cracked block yet

FYI, I've never seen a merc crack a 4.3 intake manifold unless nothing was drained properly

Thanks for the info on clearing out the milkshake. IDK, I have winterized boats 20+ times (5 different boats) with no issues until this year. Either the intake got jammed up or I missed something...

 

[mikeincolo]

Use whatever solvent you like to clean crankcase. Mineral spirits one quart with 4 30 wt oil qts works. Run sound engine on muffs with new filters and oil changes til not too milky. Then let heat soak burn off the rest of the water

This is of course you've solved the issue of your water contamination, can't rule out a cracked block yet

FYI, I've never seen a merc crack a 4.3 intake manifold unless nothing was drained properly

 

[mikeincolo]

Cylinder Compression Test: I performed compression test when engine was cold, will test again hot - once assembled and running again. Expecting increase of 20+ psi when done while engine is hot. I will update when I complete the test.

Intake Manifold Drain Plug: I have now seen several posts, iBoats and elsewhere, that the vortec intake manifold plug should be removed to drain water before storage... a step that is now part of my winterization check list.

Drain Milkshake Oil From Motor: I was able to get about 10 quarts of milkshake to drain - stored boat in my closed-up garage with oil-drain tube out back into 5 gallon home depot bucket. It is a west facing garage, got hot and stayed hot (100+ F) for a few days - and was able to get the 10 Gal of shake outta the motor.

 

[Scott06]

Cylinder Compression Test: I performed compression test when engine was cold, will test again hot - once assembled and running again. Expecting increase of 20+ psi when done while engine is hot. I will update when I complete the test.

Intake Manifold Drain Plug: I have now seen several posts, iBoats and elsewhere, that the vortec intake manifold plug should be removed to drain water before storage... a step that is now part of my winterization check list.

Drain Milkshake Oil From Motor: I was able to get about 10 quarts of milkshake to drain - stored boat in my closed-up garage with oil-drain tube out back into 5 gallon home depot bucket. It is a west facing garage, got hot and stayed hot (100+ F) for a few days - and was able to get the 10 Gal of shake outta the motor.

Once you get it back together pressure test the cooling system to make sure there are no other cracks. If ok use mineral spirits or kerosene, crank it on starter drain and then get it running and change oil repeatedly until clear. You can let it idle on 3 qts of cheap oil, change oil and filter , repeat as needed.