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4.3LX with Milky Oil

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Spage2

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Looking for some advice. Probably won't like the answers, but I'm hoping for the best.

I have a 1998 Mercruiser 4.3LX with Alpha One Gen 2 drive. Raw water cooled, always run in fresh water since I've owned it. The boat sat up for about a year and I decided to sell it. First I wanted to get it running right. Did a little fuel system work, then discovered the bellows were shot and leaking. Did a complete bellows/gimbal bearing job on it and tested. Everything seemed great except a little clicking when I turn, so I pulled the drive back off and replaced the U-Joints. This weekend I put it back on the water and thought I finally had it ready to list, but when I got back to the no wake near the ramp I was idling in and got a high temp alarm. I shut it down immediately and a boater helped me to the ramp since we were so close.

When I got it home I noticed the O-Ring for the water pickup tube must have slipped off while I was reinstalling the drive. I was hoping that was the reason it overheated, but after checking a little closer I noticed the oil is very milky. I pumped out about 6.5 quarts of milky mess tonight. I was thinking the next step would be to flush it with new oil to get the moisture out and prevent further damage, but I've never had this problem before. Any advice on what to do next / first? Is there a chance I can salvage this engine or am I wasting my time and money at this point?
 
Milky oil doesn't always mean cracked block.Do a couple oil changes and see if that changes anything.
 
Spage2 said:
Looking for some advice. Probably won't like the answers, but I'm hoping for the best.

I have a 1998 Mercruiser 4.3LX with Alpha One Gen 2 drive. Raw water cooled, always run in fresh water since I've owned it. The boat sat up for about a year and I decided to sell it. First I wanted to get it running right. Did a little fuel system work, then discovered the bellows were shot and leaking. Did a complete bellows/gimbal bearing job on it and tested. Everything seemed great except a little clicking when I turn, so I pulled the drive back off and replaced the U-Joints. This weekend I put it back on the water and thought I finally had it ready to list, but when I got back to the no wake near the ramp I was idling in and got a high temp alarm. I shut it down immediately and a boater helped me to the ramp since we were so close.

When I got it home I noticed the O-Ring for the water pickup tube must have slipped off while I was reinstalling the drive. I was hoping that was the reason it overheated, but after checking a little closer I noticed the oil is very milky. I pumped out about 6.5 quarts of milky mess tonight. I was thinking the next step would be to flush it with new oil to get the moisture out and prevent further damage, but I've never had this problem before. Any advice on what to do next / first? Is there a chance I can salvage this engine or am I wasting my time and money at this point?
Click to expand...
You can pressure test the cooling system to see if you have a leak into the oil from the water jacket. Also possibele the area under the thermostat corroded and is pushing water into the oil. How was it winterized last time . Yes change the oil and run it reapeatedly until it comes clean, but if you have leak in the water jacket it will keep getting water in there
 
Look at the spark plugs to see if one is cleaner than the others. You could have a bad manifold or riser gasket allowing water into the cylinder thru exhaust valve.
 
Didn't make as much progress as I would have liked today. Forgot to turn on the hose before I cranked it up on the muffs. Probably burned up my impeller. After I realized what I did I tried to check if it was pumping water and I don't think it is.

Went ahead and changed the oil in it twice and the oil is looking much cleaner now, but still a little bit of water in there so I'll probably do at least one more oil change on it. If it isn't pumping water I suppose I can't tell if the problem persists. I'll have to replace the impeller.

Haven't pulled the spark plugs yet but I'll definitely try to do that soon. I'm not entirely sure how to pressure test the cooling system. My thought is I need to pull the hoses off the exhaust manifolds and plug those, then connect the water inlet hose to the pressurized air, pump it up to around 10 psi and listen for leaks?

As far as winterizing goes, I'm in south Louisiana and we rarely get temps below freezing. Even then it's normally only a few hours and not far below freezing. Boating season is pretty much year round here. I've never done much in the way of winterizing. Right now it seems like that may have been short sighted. If we are going to have extended freezing temps I usually put a heat lamp on it. Just 3 weeks ago I ran it for 2-3 hours with no issues other than the clicking U-Joints. Seems like I would have had problems that day if it had frozen over the winter?
 
Spage2 said:
Didn't make as much progress as I would have liked today. Forgot to turn on the hose before I cranked it up on the muffs. Probably burned up my impeller. After I realized what I did I tried to check if it was pumping water and I don't think it is.

Went ahead and changed the oil in it twice and the oil is looking much cleaner now, but still a little bit of water in there so I'll probably do at least one more oil change on it. If it isn't pumping water I suppose I can't tell if the problem persists. I'll have to replace the impeller.

Haven't pulled the spark plugs yet but I'll definitely try to do that soon. I'm not entirely sure how to pressure test the cooling system. My thought is I need to pull the hoses off the exhaust manifolds and plug those, then connect the water inlet hose to the pressurized air, pump it up to around 10 psi and listen for leaks?

As far as winterizing goes, I'm in south Louisiana and we rarely get temps below freezing. Even then it's normally only a few hours and not far below freezing. Boating season is pretty much year round here. I've never done much in the way of winterizing. Right now it seems like that may have been short sighted. If we are going to have extended freezing temps I usually put a heat lamp on it. Just 3 weeks ago I ran it for 2-3 hours with no issues other than the clicking U-Joints. Seems like I would have had problems that day if it had frozen over the winter?
Click to expand...


you correctly outline how to pressure test the cooling system. Will get leak into crankcase and out valve cover.

on the no water in oil first time out when my neighbor didn’t winterize properly it took 2-3 outings for water to start getting into the oil on his .
 
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