Oil in gearbox

[markhankey]

Hi folks - I have come across a problem which has outfoxed me. When I checked the gearbox oil it looked milky, to me this indicates that there is water in it. Over the winter I got the cutless bearing changed but I don't think that would affect things.

Does anyone have any ideas as to where/how this water got in?

Thanks

Mark

 

[dukes4monny]

Most probably condensation.......change the oil and keep an eye on it.
Probably caused by lots of short but hard uses.....everything heats and cools rapidly and doesn't have enough time to evaporate off any moisture........that's my guess anyway.

 

[nordic_ranger]

It sounds like an oil seal has given way. However you don't say what type of engine and gearbox you have. That would possibly help solve the matter in giving advice. Your probably right about the cutless bearing being a red herring.

 

[PCUK]

If the gearbox has an oil cooler that will be the problem.
Otherwise severe condensation as already mentioned. Oil seals can't cause water ingress and the cutless bearing is a totally unrelated item.

 

[markhankey]

Thanks for the responses folks - the engine is a Yanmar 3GM 30

 

[nordic_ranger]

[ QUOTE ]
Oil seals can't cause water ingress

[/ QUOTE ]
Oh yes they can and do especially with the old Vire engines.

However it is most certainly not the case as the engine in question is a 3GM30 so it is most likely as you say to be condensation.

 

[VicMallows]

[ QUOTE ]
[ QUOTE ]
Oil seals can't cause water ingress

[/ QUOTE ]
Oh yes they can and do especially with the old Vire engines.



[/ QUOTE ]

And also with BUKHs ! Before I fitted an automatic bilge pump, my engine sump would fill with rain-water to above the level of the gearbox output shaft, and water would enter through the seal, as well as the oil leaking out. (and surely any standard lip seal will let an external fluid IN easier than the oil out ?).

(replacing the seal is trivial ..... undoing the coupling flange a nightmare ....but that's a long story . /forums/images/graemlins/frown.gif

Vic

 

[VicS]

[ QUOTE ]
and surely any standard lip seal will let an external fluid IN easier than the oil out ?).

[/ QUOTE ] yes they will work better one way than they do the other regardless of the fluid.

If you look at outboard engine gear boxes, which spend all their working lives underwater, unless they are fitted with special seals both the drive shaft and the propshaft are fitted with two seals, sometimes identical. One fitted one way round the keep the oil in and the other the opposite way round to keep the water out.