Port identification request

[DoubleO7]

I have a 1995+/- Yanmar 3 cylinder diesel in a Gravely mower.
In the picture below, I have circled a hex headed plug in the block. It is about two inches northwest of the stock oil pressure switch for the idiot light.

What does that hex head plug lead too?

Another oil pressure port that could be used for an actual pressure gauge?

 

[winston-HT]

With engine model number might be able to locate the plug in the parts manual. That is if that parts manual is available on line.

 

[DoubleO7]

With engine model number might be able to locate the plug in the parts manual. That is if that parts manual is available on line.

engine is a
3 TNE 82A

I have the Yanmar service manual but no parts list that shows that plug or the oil pressure switch.

Per you suggestion I went and found a parts catalogue PDF that explains it as the coolant drain plug!

I should have been smarter and looked for such a parts catalog in the first place!

Here is a link to it for downloading for others:

https://www.lozeman.nl/wp-content/themes/pixel-example/onderdelen_tekeningen/Motoren/Yanmar%20Motoren/3T/3TNE/3TNE82/3TNE82A/3TNE82A-YBD.pdf

 

[winston-HT]

Glad you figured it out.