Missing plug on Volvo Pent 5.7 GSI?

[Peng Bai]

Hi All,
I've been trying to find a similar post but haven't had much luck. I was changing out the oil filter on the port side of the motor when I noticed 2 threaded sockets, circled in red, that was just empty. I recently bought this boat (2000 Monterey Montura) and I'm pretty sure that the sockets were like this during the sea trial (in which it performed pretty well).

Wanted ask the more knowledgeable folks here if I am missing plug(s) or if it is supposed to be open like that.
Thanks!

 

[alldodge]

Its made like that, don't worry about it

The blocks are made for cars and trucks, the marine business use the same blocks and use there own way. Without an in depth look, the bottom is drilled out for a dipstick and the threaded boss above would hold it. The marine installs the dipstick in the pan and its bolted at another location

 

[Peng Bai]

thank you!