400: Slightly milky oil in saildrives

[b_rodwell]

The oil in both of my SD60 saildrives is slightly milky. Just a pale grey; I can still see the oil.

For one of them this could be because I reversed onto a fishing line that I was trailing! Not sure why the other one shows water ingress. I note that the sail drive oil level for a Lagoon 400 is above the sea level. I would hope this would minimise the ingress of water.

What are the risks in continuing to use the motors? I would prefer to do this until my next scheduled haul out when I will replace the seals. This could put another 60 hours on each of the motors. Naturally I don't want to add to the damage that is already there.

Thanks
Brian

[arsenelupiga]

change oil. maybe was one off ingress and problem will be gone. At least will decrease % of water for a while.

I have 20 L of gear oil for this purpose.

[Captain Bill]

90W marine gear oil contains emulsifying agents that isolate the water and protect the metal from some water in the unit, but SD60's use engine oil which may not have these agents. I would change the oil immediately and if the water reappears I would have the boat hauled and the seals replaced. I use Rotella 15w40 in mine and would not trust it to protect the metal.

[denverd0n]

The risks are pretty significant. You need to change the oil ASAP. Oil is a great lubricant, but an oil/water milkshake... Not so much.

[ggray]

When I had to do this years ago, I could remove only about 1/3 of it at a time. So I did it 9 times with a short run at the dock in between before I was satisfied.

[Aquadome]

Huge risks ... change oil as you have water contamination in the oil. Water penetration is signs of a leak so get boat serviced.

[foxfire]

Change your oil right away. I have installed header tank reservoirs on my sd20 sail drives which are mounted high above the water line to maintain positive pressure at the seals.

In the event of a seal leak it will let oil out before it lets water in, and a quick glance at the semi-transparent plastic header tank tells me if I have lost any oil.

[AndyBerry]

Originally Posted by foxfire

Change your oil right away. I have installed header tank reservoirs on my sd20 sail drives which are mounted high above the water line to maintain positive pressure at the seals.

In the event of a seal leak it will let oil out before it lets water in, and a quick glance at the semi-transparent plastic header tank tells me if I have lost any oil.

Great idea. Any tips on installation?

[Sailorman Ed]

I have installed header tank reservoirs on my sd20 sail drives which are mounted high above the water line to maintain positive pressure at the seals.

I was just talking about this an hour ago. Since oil floats on water, how much higher does the oil level need to be above the water line? I was going to drill and tap a "polyflow" fitting into the SD20 fill cap and run a length of tubing up above the WL. We were discussing how large a diameter I needed to allow the air to vent past the oil.
Got a picture of your header tank reservoirs?
Ed

[tuskie]

Hi Brian. I'll go along with the gang and say "change it". Do you have a vacuum oil extracter and spare oil? If you do it's a fairly quick and easy job.
No need to panic however, the fact that you have milky oil means that it is emulsifying water. In the meantime, running the gearbox regularly will keep the water emulsified, so that's better than letting it sit.
I'm a bit skeptical about saildrive oil header tanks. They may be fine on some models but not others. The Yanmar SD50s; that well documented piece of crap, were originally sold with an incorrectly high oil level. This caused input shaft oil seals to blow out due to oil pressure being too high. The solution; replace oil seals and retrofit a new longer oil dip stick, so less oil and more air space above the oil. This happened to our SD50s in the first few hundred hours. Fit an oil header tank to a SD50 and this problem will no doubt reappear.

I hope your SD60s are an improvement.

[ggray]

I doubt any reasonable static head would result in the kind of pressure differential that can occur in an unvented system. My fluid level is maybe a foot and a half above the waterline.

I made my header tanks out of 5 oz Lucas fuel injector cleaner bottles (seems they were a little bigger back then, maybe). Cut the bottoms off, and glued a 1/4"NPT X 1/4" barb fitting in the mouth. Popped the threaded part out of the cap of a gallon pink antifreeze jug, and used as the cap.

I threaded one of those pinch valves on the tube so that it could be closed if the cap needed to be removed, although in the 12 plus years I've had this, I don't think I've removed the cap except after the sail drive was drained at haul out.

[sapient sue]

The answers you have received are fair warning. Change the oil immediately and head for a haul out ASAP. Water in the gear box is not a good thing. I know this situation well, we have hauled out on 2 occasions because of milky fluid and though it seems expensive to haul out for a simple oil seal which can be fixed in minutes - it is the only reasonable option if you want to preserve your gear box.

Good luck and watch out for fishing lines they strip seals pretty regularly.
Cheers Sue

[Emerald Sea]

The same thing happened to our SD60 - fishing line around the shaft that penetrated the seals allowing water ingress. I changed the oil immediately and thereafter each time I saw it milky. It was only a few months before we could haul out as we were in Madagascar at the time. This is your only defence until you can haul out - continually change the oil, as simply, water reduces the viscosity of the oil with damaging effects to your gears. And order up your shaft seal kits if you haven't any with you.

Having said that ... if you are able to haul out now .... that is the prudent thing to do.

[arsenelupiga]

i quite smartly topped up saildrive with fuel additive. Additive and gearbox oil bottles are black and same shape. Initially thought it was water ingress.

I store now fuel additive in separate area.

[belizesailor]

Originally Posted by b_rodwell

...

For one of them this could be because I reversed onto a fishing line that I was trailing! Not sure why the other one shows water ingress. I note that the sail drive oil level for a Lagoon 400 is above the sea level. I would hope this would minimise the ingress of water.

...

Fouling a line is one of the most common ways to damage seals. Heavy test mono can also score the shaft, requiring repair/sleeving/replacement before it will seal again. Inspect the sealing surface on the shaft when replacing seals. If it is scored, they wont likely seal effectively.