Whats the best way to get water out of oil?

[Hifirush]

Hello All,

I went to my boat a couple days after New Years and was hoping to enjoy a day cruising quietly around, but instead found water in my oil on the starboard side. It was milky oil on the dipstick and was over full about 1/2 quart. The last time I checked my oils, which was before my last cruise, roughly mid Novemeber, they were both fine with no signs of water, and nothing during the cruise was out of the ordinary, the engines ran great.

Obviously, something is amiss. Possibly blow head gasket, or inake gasket is bad or even a bad/leaking oil cooler. I will give my beasts a compression test, that will tell more. But I have pretty much decided to take both engines down to the block and redo the heads, send out my injectors and give both engines a good “upper” overhaul, just bringing it back as close to new as I can. I figure, if I’m tearing them down, why not just knock it all out, since I’m doing the work myself. As crazy as it sounds, I’m actually looking forward to doing this.

But first things first, how to get the water out of the engine? I’m afraid to start the engine, but obviously I’m going to have to at some point. What do you think is the best way to do this? Can I remove the distributor and stick my oil primer to move the oil around, although it wouldn't be warm...? Any help on this would be greatly appreciated!

Matt

 

[Crushin It]

You'll need to suck the oil/water out just like an oil change. May have to do a few times. Sounds like you may have rot or leaks in older exhaust manifolds or risers or the block rusted a hole. When were the exhaust manifolds/risers last changed? Issues usually start with them. I'm sure others will chime in here...

 

[SloBurn]

Probably manifolds are leaking. Yup, suck it out through the dipstick hole. I've done this twice to different boats now, and I give them a rinse with kerosene after the first drain, just pour it down the fill openings, and suck that out, too. I would then change oil, run for 5 minutes, change again, and the oil would look ok after that. Current boat has put over 100 hours on it since doing this, and all's well!

 

[Hifirush]

Thanks!

Villain Style, the PO said the manifolds and risers were changed a year ago (prior to my purchase), and I have owned it for 9 months, but so far, I doubt many things he told me. You may very well be right about the issues. I am going to replace all of them too, unless by some amazing fluke they are in excellent condition!

Sloburn, how much kerosene do I put in? 7 quarts like the oil? Should I run it around with my oil primer? I’ve read elsewhere of using kerosene, i just don’t know how much!

Matt

 

[northern]

I had a heat exchanger fail on the engine oil cooler. Oil pressure alarm went. I checked oil level there was none. We were in 6 foot waves on the bow had 20 knots to go. Filled the engine with oil and continued on. Think I filled it twice. When we arrived alive shut down engine and 2 hours later checked engine over. Lots of salt water in engine. Looked for cause many hours later figured out oil cooler. Replaced oil cooler with strait pipe. Changed oil ran to temp changed oil probably total of 4 times. Still milky was 100knots from home port. Oil pressure alarm came on and would not go off oil pressure gauge was OK. When we arrived at port oil was clean no water. Changed oil. We had just purchased the boat. It had 650 hours on it. It now has 2300 hours and engine is fine.
I would not flush the engine with anything as you will get no lubrication when you turn it over. Oil is cheaper than engine rebuild. A real mechanic could probably tell you if a flush is a good idea or just many oil changes.
Seems the long run got the water out as the half hour warm ups between oil changes did not clean the oil up. Oil filter did not clean the water out of the oil. Wonder if a fuel filter would take the water out of the oil?

 

[BillK2632]

Pull the plugs first to see which cylinder are getting water in them. If the manifolds / rises were recently replaced I would look at the riser joint. Why would the manifold / risers be replaced on a freshwater boat? Freeze damage? Was it in salt water before you bought it?

 

[Hifirush]

Bill, the boat was a salt water boat. I brought here from Florida.

Matt

 

[BillK2632]

With it being freshwater if it is due to the riser joint leaking you might be ok. Don't let it sit, that's where the damage is done. Water drips into the cylinders with open exhaust valves when you shut the engine off. It sits/rusts and eventually the valve either doesn't seat or bends. I would pull the plugs, squirt some oil into each cylinder and turn it over by hand before trying to start it. Time and rust is your enemy right now.

 

[OldSkool]

I did not see the hours on the engines. If you do an upper end rebuild on a high hour engine you could be asking for trouble in the lower end. The higher compression could cause ring failure, rod/main knock or heightened crank case pressure.

 

[Ike]

Could be something disastrous, could be as simple as a leaky gasket. That's what mine was. Usual recommendation is change oil and filter. Run until engine is up to normal op temp. Change oil again. Repeat three times or until no milky oil. Best diagnostic is a leak down test. They are right, oil is far cheaper than a rebuild.

 

[Hifirush]

OldSkool, the engines have roughly 700 hours on them. I didn’t think about the lower end. A leak down test will let me know the condition of the bottom, at least as far as the ability of the engines to hold compression, and if there is a leak (which there will be) where it is. If the rings are good, I would hope the bottom end would be in decent shape for the top end rebuild, what do you think?

Bill, thats good advice, I need to get that bad oil out ASAP.

Matt

 

[Sublimetime]

the first thing you should do after you change the oil 3 times is some research on your particular motors. From 1998 to 2002 mercruiser had alot of issues with 7.4 big blocks, and now well known facts about "water reversion" caused by cam overlap. In short- at idle speed and up to about 1300 rpm these engines dont FLOW enough air thru them to overcome cam timing valve overlap and create a negative pressure zone in the exhaust elbow, which in turn gets back into motor every time you shut down. I had a boat repowered with these motors.

Are they full raw water cooled or the half/half system with anti-freeze blocks and raw water manifolds ?

 

[Hifirush]

Sublime, they are raw water cooled. Do you know what the fix was for the inversion? If I understand it, it's just raising the elbows higher with a spacer, is this what the fix was? I am not sure that is the case, but will look at it. How would I find out I have one that is susceptible to inversion?

Matt

 

[Sublimetime]

mine were 385 hp 7.4 mercruiser horizon motors. I think the hp rating is key, as this is were cam timing comes into play. As I asked about your "cooling" setup, this was a big concern also. The higher hp motors had Half fresh water cooling and half raw water setup-- meaning that the block is fresh water cooled and the manifolds and elbows (and spacer blocks) were raw water cooled. After running boat for the day ,as you come back to dock at idle speed, engines stay at normal temp and the manifolds cool off very quick. This causes the very humid exhaust gases to condensate inside manifolds and risers (same as it does in the exhaust pipe on your car and drips out the back) and then get sucked back into the motor during slow speed cam/valve overlap.

mercruiser fix: turbulator plates inserted between elbow and manifold. search for dry joint block off turbulator plate. I bought these and cut off the "ears". then the fit the old style wet joint manifolds... They create a small ledge in the manifold that catches any water dripping and steams it away.

I installed those plates, and I changed over to full fresh water cooling so manifold would run at same 185 degrees as motor temp. First four years I had those motors I did three rebuilds. After I made changes, motors went 5 years no more problems.

 

[Hifirush]

Sublimetime, thanks for the clarification. I can say my motors are the 7.4 MPI, (Mk VI) 310 HP models. I understand the cam timing thing, creating a back pressure I believe that helps with reversion. I should be OK there, but as soon as I pull the manifolds, that will tell. Once I get the water out, I am going to run a compression and leak down test. I'm very curious to this results.

Matt

 

[IanBat]

Same motors. Happened 2 months ago.

Due to back issues and business and personal comittments I had a friend send one of their marine mechanics down. As I told hime the engine was running fine, just milky oil.

Mechanic rang to check with me a few times. Manifolds had just been done. He pooped all spark plugs, compression was perfect. Changed oil out, engine was running perfect. Finally found the heat exchanger underneath the engine. New exchanger, couple of oil changes, all good

 

[Hifirush]

Ian, I would love it if it was that easy! I am going to gave to look at the oil cooler, if that is it, great!

Going to head to the boat this Friday night and spend the weekend with her. First thing get the oil out, then check a couple of quick issues but then run my compression checks and leak downs. I need to get the overall health of the engines.

I had compression check with my survey, all cylinders were very close to each other, but in low 130's into 125ish. I'll compare that to what I get this weekend.

Matt


Sent from my iPhone using Tapatalk