(Cracked Block) - Sudden Milky Oil - 351w |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Posted: April-18-2015 at 11:15am |
I thought I was done with this milky oil BS. The whole reason I swapped the 351w for the 302 was the 302 had milky oil. I've ran the 351 for 3+ hours since the motor swap with clean oil every time... Except last night / today.
I've been running the boat off the hose the past few days while working on the carb. Last night I noticed one drop of water on the dip stick, oil was still clean so I wiped it down, checked again and it was gone. I dismissed it as condensation. This morning I slipped the Tique into the lake, hooked up my vac gauge to the PCV intake and took it down the lake to warm it up. I opened the engine cover to adjust the idle when I noticed the unplugged PCV hose had puked about a 6 ounces of milky oil all over the engine bay. I immediately shut down the motor & checked the stick. 6" up the stick was chocolate milk. I limped it back to the ramp and brought it home. No dirty plugs, which I was really surprised with because the motor was running extremely rich just the other day. I mean the plugs were pristine. I checked the compression and was between 110-120 on all cyls. There must be a huge leak to fill the pan that much with a 1 min ride down the lake & back. Where to I go from here? |
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Fl Inboards
Grand Poobah Joined: January-20-2008 Location: United States Status: Offline Points: 2092 |
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intake manifold or gasket, head gasket or head crack, worse case crack in water jacket on engine block.
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Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.
1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
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jimsport93
Platinum Member Joined: February-20-2008 Location: Alpharetta Ga Status: Offline Points: 1750 |
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Sorry to hear the bad news Andy. Hopefully, you can get her up and running again quickly!
Have really enjoyed your thread. Great work. |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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I know how you feel Andy I had it happen last fall. Hopefully it will just be a gasket
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Aside from just crossing fingers & replacing gaskets is there any good way to go about narrowing it down?
I pulled the valve covers and the plugs in the heads are in great shape so no luck there. |
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65 'cuda
Platinum Member Joined: July-12-2005 Location: Cincinnati, OH Status: Offline Points: 1091 |
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Carefully disassemble, I had a head gasket failure due to a broken distributor, I could see the track across the surface of the gasket and the block where the water crossed. Was a very small area, not more than a 1/4 inch. But it put a lot of water into the oil. I also think a bunch of air gets emulsified in making it look worse than it is.
if you don't find an obvious track across a gasket surface, then you will have to dig deeper. Drain, fill with new oil, warm it up, and repeat until the oil is clear again. |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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I'm currently installing new valve cover gaskets & plan on doing an oil flush & change. I'm positive it will happen again, but I want to make sure I can duplicate the milky oil I got at the lake in the driveway hooked up to the hose. Plus I found a hand tight intake manifold bolt so I'm going to torque the intake and re-test.
If that fails it'll be time to pull the heads & exhaust manifolds for a go-for-broke inspection. |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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I had ran mine in the spring to get it to the boat ramp and had no problems. In the fall when I was done with the hull work I was running it on a hose just to warm it up to change the oil. Saw the shake but it did not seem to add much volume. Dejected I talked it over with Tim and he had made some recommendations. Did a compression check and noticed a little water on #7 plug. Pulled the manifold and you could see the rust streak in the port and manifold already. So you should be able to see something if your getting that much water. Good luck hope it's something simple
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Smithfamily
Platinum Member Joined: December-26-2007 Location: Orlando, Fl Status: Offline Points: 1602 |
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That sucks Andy! Really sorry to read that. Good news, plenty of time to figure it out before your season kicks in. Good Luck!!
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Js
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Update: I drained the oil last night, took out about 1-3/4 to 2 gallons of chocolate milk. It didn't separate much over night so I can't really determine how much air / water / oil there was.
Edit: I did add about 2/3 - 1 qt of diesel for the last 10 seconds of the engine flush so that wasn't accounted for in the volume total above. I finished changing the oil this morning, hooked it up to the hose & fired it up. In was expecting to run it for 5 min and see milky oil. I ran it for 30 min from idle to 3000 rpm trying to simulate my pass at the lake yesterday. The motor acted normal, good oil pressure, smooth operation, thermostat opened & closed a half a dozen and every time I pulled the dipstick it was at the same level with clean oil... WTF? I mean this DOESN'T happen, the oil level can't be 2-3" higher with milky oil one day then after an oil change be fine the next day. The only think I can think of is Friday during / after my carb test I accidentally left the hose hooked up and ON for 10-15 min after shutting the motor down. If there was a leak in the exhaust manifold perhaps it forced its way into a pistol and leaked passed the rings and into the crankcase over night. Then I fired it up in the AM to find a milky mess. I'll let it cool down today and pull the plugs this afternoon. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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I think you might be onto something there... I forget the details of how this happens (and it's been explained to me a couple times), but somehow if an exhaust manifold or associated gasket is weak/compromised, an engine that is being forced water on the hose is more prone to ingesting water than one that is sucking up it's own from a bucket. But, this shouldn't happen unless there is already an issue, but forcing feeding it water from the hose brings out the weakness. |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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I pulled the plugs after a 4 hour cool down & the plugs are clean.
Reinstalled plugs, hooked up to the hose & rain again for another 20 min, still Clean Oil. Both of my last 2 runs I turn on the hose as soon as the motor fired, as opposed to turn it on before like I would prior. Of course still not in the clear because that water had to come from somewhere, but it's better than finding water pissing out the dipstick hole. Maybe the boat changed it's mind when threatened to cut it up into another bar if it didn't get it's sh*t together. Or it finally realized just who it's F-ing with. One statement went through my head a lot this weekend, and it's something we should all remember: "If man put it together, it can be fixed". |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Andy,
What's you set up with hooking up the hose? Is it a "Timmy Tee" which does not valve off the hull pick up or does the hook up see whatever pressure is at the hose? |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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It sees whatever my well pump is pushing, and I'm guessing that's not a good idea?
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Andy,
Set up your hose connection like Tim has recommended and many have followed. It's been posted several times but here's a recent thread (Disregard the picture of CQ!) The RWP will suck what is needed and the rest of the water will go out the hull pick up or all of the water if the engine isn't running. |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Well there's a hell of a concept , that'll be installed ASAP.
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Guess it all comes down to this afternoon: I'm going to pull the plugs one more time and crank it over by hand to see if any of the cyl's have water in them, if not it's off to the lake to see what happens.
I also picked up a 40" USB Bore-scope camera for 20 bucks on Amazon. That way if the water does returns I'll start by pulling the exhaust hoses and go looking for signs in the exhaust manifolds. Wish me luck. |
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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I'm betting the hose left on with engine off caused your milky oil. I'm also just a little bit curious about a hand tightened manifold or head bolt.
I'm always afraid of the hose filling the engine, so I start engine, turn on hose, turn off hose, turn off engine. Hope that's all it is 😅 |
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2008 MasterCraft 197TT
1996 Nautique Super Sport 1988 Waterlogged Supra Mariah |
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Waterdog
Grand Poobah Joined: April-27-2006 Location: United States Status: Offline Points: 2020 |
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My Silver Nautique had a cracked block above the cam bearings and only leaked every now & then. Plugs were clean and ran very well but it filled the block up with water. It did that for 3/4 weeks before I found it... Good luck!
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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I'd like for someone to explain the path that the water would take if they think a garden hose can somehow force water through the RWP and into the cylinders (or oil).
I hope you're in the clear Andy, but I've never been so lucky. Compression test being good is a good sign, but I would bet you'll see it come back after you get a load and some heat cycles on it. Exhaust manifolds are the most vulnerable to an overheat in my experience, I've cracked a few pairs. Freeze damage might point to the intake. The former would result in some evidence of water in the cylinders. The latter would require pulling the intake and inspecting the valley. Hopefully it's one of those and not the block or heads. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Well, I remember it wasn't so much a matter of "forcing." It was more a matter of a leak between the exhaust port and the water jacket within the Edit: EXHAUST manifold. Then, if the engine is running, the escaping exhaust blows out any potential water. But, if the engine is not running, water is still going through the cooling system/exhaust manifolds etc. with the garden hose connected in a positive fashion. Water then has the potential to find it's way into a cylinder through an open exhaust valve. Of course, this scenario requires and exhaust manifold that is already compromised. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21169 |
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A cracked exhaust manifold will leak regardless of the method used to cool the engine. It is caused by water in the manifold leaking (internally) from the water jacket. It doesn't matter if the water came in via hose (bucket, tee or direct) or if the boat is in the lake. The most stringent test is one where you put a good heat load on the manifold (running the engine under load) so as to expand that crack.
If the manifold isn't cracked internally, water will not enter into the cylinders even if the hose is pumping water through the engine without it running. To imply otherwise is confusing the issue. |
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Mountain Man
Senior Member Joined: May-09-2014 Location: Brevard, NC Status: Offline Points: 124 |
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A Ford based 351W can also leach water into the oil via the front timing cover. Consider all possibilities and systematically test it before deciding what to repair. Good luck!
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mamigacz
Groupie Joined: June-08-2014 Location: Wisconsin Status: Offline Points: 96 |
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It never occurred to me that this could happen until I looked closer at a picture of the back side of the timing chain cover. If the gasket failed between the water port and timing chain cavity, wouldn't you see the leak dripping down the front of the engine? |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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The first thing I need to do is duplicate the problem. I may not be able to explain the how or why just yet, but until it comes back under normal operating conditions there may not actually be a problem.
Hell, for all I know some disgruntled mastercraft owner could have come by and poured a quart of water in my motor just to give me a heart attack. That being said I'll take a cracked intake, cracked exhaust manifolds, or even cracked heads any day as long as the block is spared. I can assure you a full motor rebuild is not in the budget. As for the hose hookup I can attest to the fact that with the engine off there would be some water coming out the exhaust so it must be getting past the RWP. Even then the path of least resistance should be through the exhaust manifolds & out the tail pipes so the block wouldn't see much if any pressure. Since I ran the boat for 1.5 - 2 hours in the lake a few weeks back & the oil was clean after I'm hard pressed to believe it's lake related. Since that trip I pulled the carb for a rebuild which required me to remove 1 intake manifold bolt (that secured the throttle return spring). I spent the next few days trying to get the boat running right in the driveway. During these on / off cycles the hose was on a majority of the time. The longest hose-on time was Friday when I came inside to update my Carb Running Rich post here on CCF. In my opinion the only shot I have of it being a simple fix lies with the "loose" intake manifold bolt. The bolt had been removed for 24 hours before it was snugged up with a 1/4" drive ratchet. For all I know it started dripping water into the valley as soon as the bolt was removed and had emptied the intake manifold into engine before I reinstalled the carb & bolt. If not then perhaps it was the heating & cooling cycles during Thursday driveway tests that broke the seal, again allowing it to drip overnight into Friday. Now that I'm thinking of it I do recall seeing steam or smoke coming from the valve cover breather on Friday. It's an old motor so I didn't think much of it, but Saturday morning I removed the backfire arrestor to see if the boosters were dripping and noticed liquid in front of the choke horn. I smelled and consequently tasted the liquid, it was water. It must have condensed in the backfire screen overnight. Meaning the water was in there before I got to the lake and probably even before my Friday test. Looking back having the PCV valve disconnected and it puking oil all over was a blessing in disguise. Had I not seen the milky mess on my first pass I would have continued with the plan to take my buddy footin' and would have almost certainty smoked the main bearings in the process. I'm ashamed to say I didn't check the oil before starting the boat. I never had to worry about it with my old 2 stroke outboard. Needless to say checking my oil before each run will be at the top of my priority list. |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Tuesday Afternoon Test:
I backed into the lake, checked the oil and fired it up. She ran fine for 5-10 min on the trailer before I was confident enough to unhook it and take a spin around the lake. I drove around the lake opening the engine cover every 300 yds or so to check the oil and it's still pretty clean. The physical problem I found was the starboard exhaust riser is externally leaking at the gasket. I snugged down the bolts, but it still drips above 2k RPM. It wasn't leaking bad enough to call it quits so I proceeded to make a few more passes ranging from idle to 45mph putting in about a hour of run time. A few times when I checked the oil I would see the very faint white streak in the oil, however this seemed to dissipate later / after the run. I'm also still getting a little bit of water condensing on the under side of the breather. Since I only changed the oil / filter once after the milky oil mess this could be just residual moisture that was stuck in the motor. Having seen the external leak on the exhaust riser I pulled the corresponding spark plugs and they were still clean. My plan this afternoon is to pull the exhaust hoses & go looking around with the bore camera to see if I can't find any internal leaks or rust staining. |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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After pulling the starboard exhaust riser I was able to use the bore camera to take a look in the exhaust runners all the way up to the valves. The resolution wasn't good enough to see hairline cracks, but it was neat to see inside without taking much apart.
The riser gasket was pretty beat up, but I didn't see any rust stains or clear evidence of leakage into the exhaust. I have an idea to pressure test the exhaust manifolds in place so I'm machine the adapter and give that a shot this afternoon. If it passes I'll just put it back together and wait for it to come back. |
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Boy, my problem is eerily familiar to this one no? Sudden 1/2-1qt high milky oil, good compression, hell it's even leaking at the same exhaust manifold riser gasket.
S.O.S. - Part Deux |
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KennyStar
Newbie Joined: September-15-2014 Location: mn Status: Offline Points: 8 |
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does your motor have a cooler on it?
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kenny
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LeftFieldEngineering
Senior Member Joined: December-20-2010 Location: Monson, MA Status: Offline Points: 384 |
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Oil cooler? No. Again I'm not that lucky.
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