Bukh 20 DV (Sailboat): Apparent oil leak into bilges from cockpi

[Captain Caliamari]

Some time ago I posted about a possible rear oil seal leak which was bringing what seemed to be fairly amounts of oil into front and rear bilges when the engine was running. The oil would float on the sea water and make one unholy mess.
Eventually, the last week I managed to get my mechanic to have a third diagnostic attempt. The small oil sender at the front was loose in it's Bakelite housing and was dropping engine oil into the rear bilge; it was running down the curve of the engine. Mechanic of the opinion this would cause large quantities of oil to leak out when engine running. This is waht was happening.

Mightily relieved to get the new sensor and fit it. Did a massive clean up of the bilges which had been stained with oil. The rear bilge is obscured by the massive fly wheel so I attacked with degreaser and hot water from a jet sprayer. this from inside the lazarettes.

Time for the final cockpit clean of the year. I had not turned the engine on. Cleaned the cockpit and used plenty of hot water. Went down below to replace all the raised floorboards and screw them back down.

Bilge again full of water ( seemed to be salty - I had used a couple of buckets sale water to rinse.) with engine oil floating on top. Seemed to be water on the top of the engine at the rear in emulsified droplets. Rear bilge seemed relatively clean. Some small wet/oil at stern section.



Apart from scuppers and cockpit drains being defective and washing into the engine compartments how can this happen?

I had no time to check the piping and the valves etc. The only water used was that in the cockpit. The lazarettes were closed.I had not run the engine at all.
I have not tested the engine and new sensor fitting under load yet. Not even turned engine on.
Any ideas please anyone?
Anyone else experienced something similar?

I will go back and check today.
It's a weird one for sure.
Photos of the sensor I replaced (x1) and the front bilge (x2)