Stern drive oil coming out of reservoir

[novelles]

Hi to all, a long time since my last post, but very busy and little leisure time.<br /><br />Well, here is my question ready to hear from your expertise.<br /><br />My Bayliner 1996 Mercruiser 3.0 LX Alpha One has been resting in salty water for the last 8 months and I have to take it out of the water next week for antifouling. I just discovered today (I've just used the boat a couple of times since last summer) something that could be a problem so I would like to know just in case I have to fix it when the boat is out of the water.<br /><br />Well, I cruised at 3500-4000 rpm for about 20 minutes and when I checked the motor compartment (I do it everytime I stop the engine just to check everything is still there ) I saw there was stern drive oil spilled out of the reservoir onto the bilge, clean blue oil.<br /><br />I thought it could be due to too much oil in the reservoir so I cleaned it up with no worry. When crusing back to the marina (not even 3500 rpm this time) I got even more oil. Level is a little over the line now, and so has been other times with no spillage those times.<br /><br />Last year stern drive was removed, new elbows, new seals, new impeller, new shift seal kit, oil is perfect blue, but ... (because there is always a but) I should have probably replace the reservoir lid and I didn't. The lid has a small rubber piece in it that broke, I glued the two pieces and put it back in the small hole so I think it might not do the job. I just realized of this now at home.<br /><br />Could it be possible that if that little hole is stuck, the reservoir gets high pressure and then suddenly spills oil out? (it seems to do it on the right, just over the alternator)<br /><br />Or could it be due to oil high temperature due to marine growth on water intake even though engine temperature is in range?<br /><br />Any ideas or similar experiences?<br /><br />Thanks in advance and greetings from Spain.<br /><br />Gab

 

[NateCCIE]

Re: Stern drive oil coming out of reservoir

I dunno, but I bet if it's overflowing like that, you're getting water in there somewhere.<br /><br />-Nate

 

[gspig]

Re: Stern drive oil coming out of reservoir

Check the outdrive for water and do a pressure test.

 

[novicetech]

Re: Stern drive oil coming out of reservoir

Any hydraulic oil will expand with heat the more heat you add the more it expands, it could be running hotter causing it to expand. When you take it out of the water try to drain a little out of the fill hole near the bottom of the lower unit water is heavier than oil and will come out first. If water or milky looking you have problems.

 

[novelles]

Re: Stern drive oil coming out of reservoir

Thanks for replies. Oil is by now absolutely regular gearlube with no milky or brown colour so if its something wrong must be recent. Even though water remains at the bottom, with high RPM it should have mixed with oil already so I don't know what to think. <br /><br />If I just replaced all seals and joints last june, where could it come from?<br /><br />It really annoys me thinking of any problem with the stern drive after all the time and money I spent last year.<br /><br />Well, I guess I'll have to check it next week when I have the boat out of the water. Besides, tomorrow I will adjust oil level with the stern cold and will remove the small piece of rubber on the reservoir lid to see if it has something to do or not. <br /><br />I'll keep you informed.<br /><br />Gab

 

[novelles]

Re: Stern drive oil coming out of reservoir

Well, a quick reply to let you know how things go.<br /><br />I removed some oil to match the level on the reservoir with engine cold, then I cruised for about 5 minutes and checked again. Level was about half an inch higher, then engine was stopped for about 5 hours and level remained at that level. When cruising back to the marina, the level raised again to the top of the reservoir and oil spilled all over the bilge. Once the oil was cold again, level went down but remained half way between the level mark and the top.<br /><br />So there is for sure something going into the lube, and can be only water. It's weird that oil doesn't look any milky or brown as its suposed to turn but it might need more time to do it.<br /><br />Water just goes into the stern drive oil when cruising, not when stopped. Housing gasket, impeller housing seals and gaskets, and shift shaft kit were replaced last june.<br /><br />Could problems come from driveshaft or propeller shaft oil seals? They seem to be dificult to replace.<br /><br />Any ideas or troubleshoot guidance would be appreciated.<br /><br />Gab

 

[tommays]

Re: Stern drive oil coming out of reservoir

if you drain it and there is water than the only thing you can do is pressure check to find the leak<br /><br />the only easy to change seal is the compleat seal carrier under the pump base after that it gets pretty hard<br /><br />if you put in a compleat pump kit the carrier comes with the seals allready installed<br /><br />tommays

 

[vipzach]

Re: Stern drive oil coming out of reservoir

You need to drain all the oil from the outdrive, take a look at it, if it has water in it then do the pressure test as suggested above.

 

[Capt Ken]

Re: Stern drive oil coming out of reservoir

I'm surprise no one knew the cap on the jug is a one way valve. It sucks but don't blow. If there is fluid coming out, then either the cap ain't tight or the rubber check valve in it is bad. If anyone don't believe it, remove the cap on yours and go out for a run. The captive air in the top of the outdrive will heat up and expand and blow oil out the top of the jug.

 

[tommays]

Re: Stern drive oil coming out of reservoir

well thats the difference between a pro who sees it all the time and the rest of us who only see what broke on are boats <br /><br />tommays

 

[rodbolt]

Re: Stern drive oil coming out of reservoir

yep what capt ken says <br /> leave the cap off and see if ya dont make a mess. replace the bad cap with a good one. the orange rubber allows air in but nothing out,unless its damaged. then it will puke oil. at least ya know the line from the drive to the tank is clear.

 

[PeteHarris]

Re: Stern drive oil coming out of reservoir

If you've got a bubble in there it will warm up, expand (a lot ... it's a gas) and push oil out the reservoir .... that could account for a burb or two.

 

[Richard Petersen]

Re: Stern drive oil coming out of reservoir

O K. I ask the obvious. How do we get the captive air out of the drive top and end the pressure build up. My orange flap died & was replaced. O K now.

 

[novelles]

Re: Stern drive oil coming out of reservoir

Thanks so much for the replies.<br /><br />If I don't misunderstand, do you mean that if the reservoir cap does not seal properly I could get that much oil out of the drive?<br /><br />I thought the reservoir had two functions, one as oil reservoir (needs to let air in through the mentioned orange valve) and the other as expansion tank, like those in the cooling systems of our cars. But if as you say it works just the first way, it means all the stern drive lube is working under certain pressure when running the engine. Is this true?<br /><br />I remember now (but not sure and unable to check now) that there is a very small hole next to the orange valve which would not match this theory. It would be interesting to clarify.<br /><br />Anyway, if oil gets hot and expands, there is certain pressure that would make the oil go out of the drive when running through the leak, not water coming into the stern. That is more likely to happen when engine is off.<br /><br />As I see it (and I would like to make sure), if I'm getting that much oil level increase in the reservoir, and it doesn't go down when cold, is because something is getting in there and, as I posted before, it can only be water.<br /><br />What is hard to believe for me is that I'm getting that much water in there, just when running, suddenly from one day to another and that the oil is not milky or brown. Very weird to me.<br /><br />It is like if I was pumping water in there what makes me think of the seal under the impeller, which could be pumping water up to the engine and down to the drive. I cannot think of any other seal letting that much water in (about 20cm3 in 10 minutes time) and no oil out.<br /><br />I would like to here some more thoughts on this misterious stern.<br /><br />Thanks in advance.<br /><br />Gab

 

[tommays]

Re: Stern drive oil coming out of reservoir

like capt ken said its a ONE way valve <br /><br />tommays

 

[novelles]

Re: Stern drive oil coming out of reservoir

Yeah, you are right. I made up my mind and just remembered that the small hole is right next to the rubber valve and is in fact the air passage controlled by the valve.<br /><br />In this case, could my problems just come from the reservoir cap?<br /><br />I still wonder how long it takes for the oil to become milky if there is a leak.<br /><br />Thanks.<br /><br />Gab