Close the seacock

I empty all the water I could using the anchor wash

I took the chance to clean the strainer

Disconnect both hoses

The bottom bolt will require a wrench

Lots of corrosion after 16 year old

Where the cooler is located

Hose I changed 3 year ago

Inside the cooler

It looks to me the diameter of this new cooler was not the same as the water intake of the seacock

Unfortunately I was right... 30 mm for the cooler and 32 mm for the seacock

I was not comfortable with this difference
I was afraid that engine vibration would potentially lead to water leaks.
I also did not like the sharp turn on the hose
so I put an elbow, then with a Vetus coupler connected a 32 mm hose to a 30 mm hose.

Once re-installed, I tested the engine at the dock (adding dock lines) for over 1/2 hour.
The engine was in gear and run at various rpm

I coated the new bolt with anti-seized

not easy to hold in place

Manually bolt

Using wrench for the bottom bolt

back in place

Connect the hose

Don't forget to open the seacock - then test the engine
In my case, the cooler was leaking...
I thought it was from the hoses to and from the cooler
but was actually from the paper gasket
So I had to redo it, but this time used a gasket maker to connect the cooler and it's cover