Bukh DV20 - what is this part?

[whtrbt]

On my engine (1984 Bukh DV20), there is what appears to be salt crystals around a part and it looks like the paint has been pushed out from the inside.
It's a panel with two bolts on it that look like they're designed to be turned by hand.

Photo attached.

It's not labelled or described in the in the Owners Handbook. I've marked it's location on the second attachment.

My guess is that it's connected to the cooling system (perhaps covering a port that is only used for freshwater cooling?) and the gasket is leaking.

[Key Wester]

Looks like this plate is designed to cover a hole in the block. [ I guess that is obvious!]
The hole was probably due to a manufacturing process, similar to freeze plug holes. Since it is leaking, time to install a new gasket. First shut the c-cock, then use a hex wrench to remove the screws. Clean all parts, and the contact surface of the block. Use a thin layer of silicone on the gasket, and blue lock tite on the threads. DO NOT overtighten! or you mat squeeze out the silicone, and you will be back to square one. Joe D

[tkeithlu]

When making a gasket from silicone sticky goo, assemble the parts, wait 24 hours, and then compress/torque the parts together. That gives time for the goo to gel, so you have a compressed gasket rather than just a silicone plug.

[whtrbt]

Thanks both - first boat and I'm trying to learn to do as much maintenance myself as I can, so this is really helpful.

[Compass790]

Good advice above.
Just wanted to add the Bukh 20 will go for a very long time if you feed it clean diesel & change the oil as recommended, also anode. Get a workshop manual if you dont have one & follow maintenance guidelines.

The parts are very expensive so best to look after it.
If you scroll down to the btm of page & look in similar threads "Bukh DV 10/20 for sale & read the replies there is a blokes email offering a workshop manual in PDF form but it dates from 2012 so no idea if it will still work. Worth a shot tho.