Black water type liquid in engine bay

[thingsweregood]

Hello,

 

Another (probably v basic) question from me - I've been putting in a lot of hours cruising as I'm moving my new home to the area I want to be, and I've noticed a build up of black, quite viscous liquid in the bottom of my engine bay below the prop shaft. I've got a trad stern, so I assume it's not rainwater. I measured it with a stick and it's about 4 inches of liquid.

 

Any ideas what it could be and if I should be really concerned? Checked my oil levels and they still appear to be good.

 

And any idea for how to easily remove? It's a really long distance down and such a small space I'm not sure if I'd be able to contort myself to bail it out with a jug.

 

Thanks in advance!

[Tony Brooks]

Depends where the engine drip tray ends at the back and if its overfull, but it sounds horribly like engine oil to me. Is this an air cooled Lister? If so you may have an internal fuel leak but it would be thinner, more like diesel.

 

That 4" may well be 4.9" of water with 0.1" of old oil floating on top.

[Keeping Up]

If it's only right at the back of the shaft, it could be water that has come in through the stern tube plus (as Tony suggests) old oil on top or even used stern-tube grease which certainly drips out of mine if the nuts are a bit loose.

[Tony Brooks]

1 minute ago, Keeping Up said:

If it's only right at the back of the shaft, it could be water that has come in through the stern tube plus (as Tony suggests) old oil on top or even used stern-tube grease which certainly drips out of mine if the nuts are a bit loose.

 

I did consider that, but usually the grease tends to stay pretty much as blobs of grease and the water is no "viscous".

[Tracy D'arth]

Vac it out. Is there not a bilge pump in that chamber?

[pete.i]

You do really need to get down there and bail some to see exactly what it is. Whilst people on here are trying to guess what you have down there your engine could well be on the way to destruction.

[Alan de Enfield]

11 minutes ago, Keeping Up said:

If it's only right at the back of the shaft, it could be water that has come in through the stern tube plus (as Tony suggests) old oil on top or even used stern-tube grease which certainly drips out of mine if the nuts are a bit loose.

 

 

If it really is 4" deep that could well be above the height of the baffles between the engine bilge and the stern bilge - it could easily be a mix of oil and water, and should certainly not be pumped out into the waterway using a bilge pump.

 

You can use a Pela pump, that should do the job, and, it allows you to dispose of the oily water in a proper manner.

[thingsweregood]

Thanks all!

 

Got someone to have a peep at it, and you're right - it was oil sitting on top of water. Engine oil is at a good level, as is water/antifreeze etc. Just need to put a bit of extra oil in the gearbox.

 

One thing was that the bilge pump was sitting inside a plastic tub floating in the bottom of the engine bay so when I turned it on it wasn't pulling any water through, as it couldn't get to it. We popped the pump into the water and cleaned it out, and soaked up the surface oil with some pads.

[Alan de Enfield]

6 minutes ago, thingsweregood said:

Thanks all!

 

Got someone to have a peep at it, and you're right - it was oil sitting on top of water. Engine oil is at a good level, as is water/antifreeze etc. Just need to put a bit of extra oil in the gearbox.

 

One thing was that the bilge pump was sitting inside a plastic tub floating in the bottom of the engine bay so when I turned it on it wasn't pulling any water through, as it couldn't get to it. We popped the pump into the water and cleaned it out, and soaked up the surface oil with some pads.

 

 

Now you just need to find out how 4" of water got into the boat.

[Tony Brooks]

1 minute ago, thingsweregood said:

Thanks all!

 

Got someone to have a peep at it, and you're right - it was oil sitting on top of water. Engine oil is at a good level, as is water/antifreeze etc. Just need to put a bit of extra oil in the gearbox.

 

One thing was that the bilge pump was sitting inside a plastic tub floating in the bottom of the engine bay so when I turned it on it wasn't pulling any water through, as it couldn't get to it. We popped the pump into the water and cleaned it out, and soaked up the surface oil with some pads.

 

Unless there is a mini-bulkhead between the area you are describing and the under engine area I think taking the pump out of the plastic tub is a BSS failure and what you did may have opened you to persecution buy the environment agency by pumping oil contaminated water into the canal. It's still probably illegal but would pump such water into containers and pour it along the hedge line. If the area between the engine beds, the bulkhead and the triangular section under the gland is all in one put the pump back in the tub. Then once you have cleaned the under engine area properly use white bilge blankets to absorb the oil and fuel drips.

[David Mack]

11 minutes ago, Tony Brooks said:

what you did may have opened you to persecution buy the environment agency

Or even prosecution...

[thingsweregood]

46 minutes ago, Tony Brooks said:

 

Unless there is a mini-bulkhead between the area you are describing and the under engine area I think taking the pump out of the plastic tub is a BSS failure and what you did may have opened you to persecution buy the environment agency by pumping oil contaminated water into the canal. It's still probably illegal but would pump such water into containers and pour it along the hedge line. If the area between the engine beds, the bulkhead and the triangular section under the gland is all in one put the pump back in the tub. Then once you have cleaned the under engine area properly use white bilge blankets to absorb the oil and fuel drips.

Yep, caught the water in a bucket and put into various containers! Trying to avoid contaminating the canal we all live on Will put the pump back into the tub.

Interesting about the BSS thing... I had no idea. So what's the purpose of keeping the pump in a little plastic tub below the prop shaft then? I think the areas might be different, because there was a bit of water below the engine, at the furthest area away from the rudder, but that was definitely clear, where as under the prop shaft had the black sitting on top. Hard to see if there is mini-bulkhead dividers as it's hard to get down there.

[Tony Brooks]

2 minutes ago, thingsweregood said:

Yep, caught the water in a bucket and put into various containers! Trying to avoid contaminating the canal we all live on Will put the pump back into the tub.

Interesting about the BSS thing... I had no idea. So what's the purpose of keeping the pump in a little plastic tub below the prop shaft then? I think the areas might be different, because there was a bit of water below the engine, at the furthest area away from the rudder, but that was definitely clear, where as under the prop shaft had the black sitting on top. Hard to see if there is mini-bulkhead dividers as it's hard to get down there.

 

The purpose of the tub is to catch drips from the stern gland so they can be pumped out without risking pumping contaminated water into the canal.If there is no "mini-bulkhead" behind the engine to contain any oil & fuel drips it's not a very good design, so the tub is about the best you can do.

 

Just keep an eye on it and see how it goes.