water in oil - how many oil changes to clear?

I recently replaced the manifold on a Mercruiser 165, straight six. (Mid 70's vintage). Engine hydrolocked on me last month and I had to get towed in. Discovered cracked manifold. Ordered a new manifold and installed it - riser is like new, so no need to replace it.

I didn't notice any water in the oil when I removed the old manifold, but after starting the engine and running it with the new manifold (on muffs) I noticed the oil on the dipstick looked milky.

Sure enough, water in the oil. Changed oil and put new filter on it. Ran it for about 15 or 20 minutes on muffs. Changed that oil - it looked just as milky.

Here's my questions:

1. After getting water in the oil and solving the problem - and changing the oil and filter - should the new batch still be milky? How many oil and filter changes does it typically take?

2. Should I take the boat out and run it for awhile to truly get it up to temp and help evaporate any left over water?

Just to make sure, I pressurized the engine block - it seem to hold.

I pressurized the new manifold. It held.

I took off the riser and checked - the exhaust cavity in the manifold and riser are nice and black - no evidence of new water. So it doesn't seem to be any way for any new water to get into the oil.... but the second batch sure seemed pretty milky.

Thoughts?

Re: water in oil - how many oil changes to clear?

Ayuh,... I'd say #2, 'n watch the oil Level, vs. it's Color..

Re: water in oil - how many oil changes to clear?

I just changed and ran mine 4 times before it got clear after a slight sinking by favorite brother.

Re: water in oil - how many oil changes to clear?

marc c said:

I just changed and ran mine 4 times before it got clear after a slight sinking by favorite brother.

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You must've considered changing the brother too?

Re: water in oil - how many oil changes to clear?

Hopefully I can get out on Friday and get 'er up to temp. Weather's been beautiful and it gives me a good excuse to go burn some fuel.

I'll let you know how it goes.

Re: water in oil - how many oil changes to clear?

Just to make sure, I pressurized the engine block - it seem to hold.

I pressurized the new manifold. It held.

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What do you mean it seemed to hold?

You sound very sure the new manifold held, but why not so sure on the block?

Re: water in oil - how many oil changes to clear?

i don't know what the answer is. and ya know i'm just another joe boater marine tech wannabe... but i just had anti freeze and oil mix on my vortec 5.7 in my van. bum intake gasket, total failure. i change oil once after discovery. then the shop that repaired it gave it another oil change. do far, i've not seen any signs of anti freeze intrusion in the new oil.

been a while since i had water/oil mix in my 165hp mercruiser. but best i can remember, i changed that one 3 times before i had what looked like just plain oil. my leak was a manifold also on the 165.

so after your oil changes and yer discovery of milky oil again, did the level increase too? my 165 had a slight increase best of memory after failure. my 5.7 votec had 1.5 gal. increase after failure + anti freeze running out of the oil drain hole after removing 2.5 gal. of anti freeze/oil mix from the crankcase. after repairs on both. after the 2 or three oil changes. no chocolate milk, no level increase..

if yours is still chocolate milk after the repair and level isn't increasing. maybe condensation and still some contamination like from the inside of the valve cover???? a hard run sounds like a good idea, unless there's still a failure and your still getting water intrusion.

Re: water in oil - how many oil changes to clear?

The hotter the engine runs, the sooner the water will evaporate out. Check and make sure your PCV system is free and open and drawing air through the crankcase to help remove moisture.

Re: water in oil - how many oil changes to clear?

HT32BSX115 said:

You must've considered changing the brother too?

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Gave him a lifetime ban on all boats.
Time for him to buy his own to wreck.

Re: water in oil - how many oil changes to clear?

Evaporate? ONE oil change, new filter, and your oil will be water free. If not, then you have a head gasket leak and need to fix it.

Re: water in oil - how many oil changes to clear?

I would not wait for the water to evaporate!!!! My suggestion is to run some kerosien (or however you spell it lol) in your oil for about 5 min then drain and run fresh oil. the kero will help break up all that nasty oil and clean out the water. kero is an oil based fuel so it will be ok to run for a few min. If there is that much water in the oil you risk damaging the lower end of the motor running it too much

Re: water in oil - how many oil changes to clear?

You're assuming all the water and oil is just sitting in the oil pan. Well, it isn't..it's in the head and valve cover, in the lifter valley on the side, lotsa places. Especially if it has emulsified and formed a sludge. This sludge is all over the inside of the engine, and doesn't always drain out. As USS suggested, I've used mineral spirits rinses, but I usually pour it in the top and let it drain out without running the engine.

Re: water in oil - how many oil changes to clear?

My son had a jet ski that ingested water and even after 4 oil changes it was still a little milky. Cleared up after running it for a little while. If you take the boat out for a run, I would not tax it too much until the water is gone, and I wouldn't go too far from a safe harbor.

Wayne

Re: water in oil - how many oil changes to clear?

Beautiful day out on the water. The good news? After a good extended run the oil is perfectly clear and water free.

Alpheus said:

What do you mean it seemed to hold?

You sound very sure the new manifold held, but why not so sure on the block?

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I had to cobble together some fittings and plugs, etc to check the block. I didn't have a pressure gauge handy, so I simply removed the hose to the manifold and the hose to the thermostat housing - plugged the manifold hose up and attached a fitting and garden hose to the thermostat housing. Turned the garden hose on full blast and waited. I had already removed the cap on the oil drain hose and oil filter. I figured if there was a leak it would put some water in the crankcase and out the oil drain hose. Never did get any water - so that's why I said it seemed to hold. That was my "unscientific" method of checking.

Thanks for the help to all who posted!

Re: water in oil - how many oil changes to clear?

The good news? After a good extended run the oil is perfectly clear and water free.

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that is great news fm. so how many oil changes did it take for you?

Re: water in oil - how many oil changes to clear?

I drained out the initial oil after seeing that it was milky. Put new oil and filter in, ran it on the muffs for 10 minutes or so. Checked it, it was pretty milky. That's when I posted. Drained out that oil and put new filter on and did the extended run. So I guess that would be two oil changes. It MIGHT have cleared up with a good hard run on the first change, but I decided to go ahead and do the second one.

Re: water in oil - how many oil changes to clear?

Hard run will heat the oil and boil the water out. That's why oil temperatures should always be over 200 degrees..helps keep water out. Plus, hot oil, less friction, better engine life!