milky gearbox oil

[Paolo Reale]

Hi

Just changed the gearbox oil in my PRM150. The oil that I drained was a bit milky. Just checked the new oil now a week later and it too is a bit milky.  I know this indicates water ingress but I've no idea where from or if it's a serious issue or something I can sort when I'm back in my marina in a month or so.  Any suggestions or thoughts very welcome. 

[Tony Brooks]

I would suspect the gearbox oil cooler has a leak.

[Tracy D'arth]

18 minutes ago, Tony Brooks said:

I would suspect the gearbox oil cooler has a leak.

Most likely the cooler.  Its the only place where the oil and water come together unless the gearbox breather is getting flooded with water from the deck.

[Paolo Reale]

Yes, having read other posts, a gearbox oil cooler leak seemed the most likely. Is this major, will the water damage the gearbox? 

[nicknorman]

5 minutes ago, Paolo Reale said:

Yes, having read other posts, a gearbox oil cooler leak seemed the most likely. Is this major, will the water damage the gearbox? 

Yes it will in time. It will cause internal corrosion and of course watery oil isn’t as good a lubricant as oil so wear rate will increase. It shouldn’t be a particularly big deal to replace the oil cooler. And the leak is only likely to get worse! Might be worth considering why the oil cooler is leaking. Of course it could just be very old. But equally it could be due to a lack of corrosion inhibitor in the engine coolant water. Whilst the freeze-resisting part of antifreeze doesn’t deteriorate, the corrosion inhibiting part does, so traditional antifreeze/coolant should be changed every couple of years, maybe up to 7 years if it’s fancy modern long life stuff.

Edited July 6, 2021 by nicknorman

[Ray T]

Your gear box oil cooler will possibly look something like this:

 

 

The end caps deform over time, worth replacing.

 

 

Oil cooler in situ, gearbox removed for clarity. 

 

Edited July 6, 2021 by Ray T

[ditchcrawler]

1 minute ago, Ray T said:

Your oil cooler will possibly look something like this:

 

 

The end caps deform over time, worth replacing.

 

I had one just like that that failed

[David Mack]

9 minutes ago, Ray T said:

 

The end caps deform over time, worth replacing.

But won't cause the OP's problem. A failed end cap will result in cooling water leakage into the boat. The OP's problem is a failure of a heat exchanger tube or end plate.

13 minutes ago, Ray T said:

 

The end caps deform over time, worth replacing.

But won't cause the OP's problem. A failed end cap will result in cooling water leakage into the boat. The OP's problem is a failure of a heat exchanger tube or end plate.

Replacement cooler:

https://www.asap-supplies.com/products/bowman-dc50-oil-cooler-40hp-3-8-bsp-oil-22mm-id-water-203010

[Paolo Reale]

In the short term - I'm in London and moor in Nantwich  - would changing the gear box oil every few days get me relatively safely to a place where I could get some help?

[Tracy D'arth]

Just now, Paolo Reale said:

In the short term - I'm in London and moor in Nantwich  - would changing the gear box oil every few days get me relatively safely to a place where I could get some help?

It would help but there are lots of places and people around Nantwich who can sort this out for you. If you need help PM me.

[Ex Brummie]

How long after running the engine did you remove it?

In checking the new oil, how long has it stood from when last run?

The oil in gearboxes seems to get aerated and appear milky before it settles. Does the oil level rise over a period? If it is taking on water then you should expect to see a rise. Try draining some oil and let it settle for a few days and water should separate.

Is your engine raw water cooled or skin tanks?

Edited July 6, 2021 by Ex Brummie

[Paolo Reale]

All this has been really helpful  - thanks for the offer Tracy - it'll take a month to get back to Nantwich and I do know an excellent engineer who'll sort it for me - do you think I'll make it with regular oil changes for this length of time? 

[Paolo Reale]

Useful ideas Ex Brummie. I' ll do as you suggest as there is no rise in level which you'd expect with water getting in. It's keel cooled.  What relevance is this?

[Tony Brooks]

15 minutes ago, Paolo Reale said:

Useful ideas Ex Brummie. I' ll do as you suggest as there is no rise in level which you'd expect with water getting in. It's keel cooled.  What relevance is this?

In that case you might find oil turning up in the engine coolant. Just be aware.

[ditchcrawler]

24 minutes ago, Tony Brooks said:

In that case you might find oil turning up in the engine coolant. Just be aware.

That is how I spotted my oil cooler had gone. But that was engine oil. It was where the tube end plate was soldered to the outer tube.

[Slim]

1 hour ago, ditchcrawler said:

That is how I spotted my oil cooler had gone. But that was engine oil. It was where the tube end plate was soldered to the outer tube.

Your experience was identical to mine. To be honest changing an oil cooler, given that it's a straight swap, is fairly simple. What is a right pain in the *rs* is getting all the oil out of the skin tank. 

|To the OP. Have you not considered getting the problem resolved before travelling home?  

 

[Paolo Reale]

Thanks for this Slim. Yes, I'm no engineer but if I can order a new cooler I'll have a go at it myself.  Any thoughts about how to drain the skin tank effectively? 

[blackrose]

I used a wet vac on the end of the bottom hose but couldn't get it all out. In the end i pulled off the bottom hose, took off the coolant filler cap and let it drain onto the floor. Then used the wet vac to clean up the mess. If you're doing a complete coolant change then there's a plug you need to take out of the engine too.

[Tracy D'arth]

6 minutes ago, Paolo Reale said:

Thanks for this Slim. Yes, I'm no engineer but if I can order a new cooler I'll have a go at it myself.  Any thoughts about how to drain the skin tank effectively? 

Just dump the water/antifreeze and replace with fresh unless you can use a wet vax to suck it up and reuse it. It is probably a good idea to replace it anyway, the corrosion inhibitors being ineffective could be part of your problem anyway.

 

You don't need to drain out any more than necessary.

[Slim]

15 minutes ago, Paolo Reale said:

Thanks for this Slim. Yes, I'm no engineer but if I can order a new cooler I'll have a go at it myself.  Any thoughts about how to drain the skin tank effectively? 

The point I was trying to make was that if oil finds it's way into the skin tank it's a real pain ,not that it has.  Anyway, if you would tackle the task of changing the cooler there are any number of forum members who would give practical advice. Prehaps you could start by giving some general details such as where you presently are, make of oil cooler , dimensions of cooler, length, diameter, photos etc.

 

Frank 

Edited July 6, 2021 by Slim
clarity

[ditchcrawler]

I put a bucket under the end of the heat exchanger and loosened the jubilee clip

[blackrose]

I must have missed something. What's the specific issue with contaminated coolant in the skin tank? If it's contaminated ideally you need to get rid of all of it surely, including what's in the engine, hoses, calorifier coils, etc, not just what's in the skin tank?

[Slim]

5 minutes ago, blackrose said:

I must have missed something. What's the specific issue with contaminated coolant in the skin tank? If it's contaminated ideally you need to get rid of all of it surely, including what's in the engine, hoses, calorifier coils, etc, not just what's in the skin tank?

It's not that you've missed something it's that the topic has veered from the original point (I think). It would really benefit from a reset. As i read it the OP has a knackered gearbox oil cooler and needs to change it. It may have caused other (coolant related) issues but that's speculative at this stage.

[Tony Brooks]

9 hours ago, Slim said:

It's not that you've missed something it's that the topic has veered from the original point (I think). It would really benefit from a reset. As i read it the OP has a knackered gearbox oil cooler and needs to change it. It may have caused other (coolant related) issues but that's speculative at this stage.

 

Agreed, but it is  a very good reason to sort it ASAP and not boat halfway up the country.

 

I would also be a bit concerned about the long term impact of any water on the gearbox clutch plates.

Edited July 7, 2021 by Tony Brooks