Winterizing your inboard engine

The best checklist (until you find a better one) for winterizing your inboard diesel engine

Port Vell, Barthelona, February 2024

Canadian summers are a delight, but sailing in the winter is difficult when the lake is covered in ice thick enough to support your boat’s displacement. It’s also cold enough to crack engine blocks and other expensive things if you don’t prepare your boat for it.

This checklist covers inboard diesel engines, both raw water and fresh water cooled. I use this checklist for my sailboat’s Yanmar 2GM20 inboard.

I sail on freshwater, but this checklist should work for saltwater boats, too. It includes items for flushing the raw water cooling with fresh water.



A handy PDF for you to download and print:

Thumbnail image of the checklist


I follow this checklist in late October, maybe even November, before things start freezing overnight.

Winterizing the engine is in 2 parts, before and after haul out. I organize the steps to do as much as possible before hauling out, since electricity and running water aren’t as convenient when the boat is on the hard and tucked in a corner of the storage yard.

Before you start

See also

Changing the oil on your inboard diesel

The best checklist for changing your diesel inboard’s oil (until you find a better one)

Summerizing your inboard engine

The best checklist (until you find a better one) for getting your inboard diesel engine ready a new season

At your service

Humbly yours,

Marc, Supreme Purser