Don't Crack the Block · Winterize Your Boat Yourself

Sheet 1 / 5

Water you can't see cracks the block.

Water grows by about 9% when it freezes. Leave a little in the block, a manifold or a low hose at the first hard freeze, and it has nowhere to go but through the metal.

A BoatU.S. look at ten years of its freeze claims found that more than three-quarters involved a cracked engine block or exhaust manifold, because water stayed in the engine or cooling system.

Your deadline is the first forecast hard freeze, not a date on the calendar. Chapter 1

Sources: Virginia DWR · The Log, reprint of a BoatU.S. Magazine article

Diagram of a sterndrive engine with every drain point flagged: block drains, manifold drains, risers, lowest hoses — Fig. 4 · Every flag is a place water can stay behindp. 25

Sheet 2 / 5

What the shop charges. What you'd do instead.

Posted winterizing rates, 2026–27

Winterize outboard$120–$519

Winterize sterndrive (I/O)$325–$500

Shrink wrap, per foot$13–$22

Impeller, with winterizing$300 + parts

Tax, shop supplies, partsoften extra

Every fall, per engine$120–$519+

Every fall

Posted rates from four shops in Michigan, Ohio and Minnesota, listed in Chapter 2 (impeller: Faction Marine, Chapter 9). Your shop's prices will differ.

The same jobs, yourself

Stabilize the fuel, fog the engineCh. 3
Drain the cooling systemCh. 4
Engine oil, filter, gear oilCh. 5
Check the impellerCh. 6
Battery, cover, miceCh. 7

Your cost

The fluids and parts your manual names, and a Saturday.

Ch. 1Cracked block

One owner posted an $8,300 repair quote after his engine froze.

Ch. 5Split gearcase

Water left in the gear lube can freeze and crack the housing.

Ch. 6Cooked in May

A tired impeller quits pushing water on the first run.

Ch. 7Chewed wiring

Mice nest on board over winter and chew through wires.

Sheet 3 / 5

The parts list.

One job per chapter, in the order you do them on the boat. Each starts with the rule, ends with a checklist, and tells you when to stop and call a pro.

Written for outboards and sterndrives under 26 feet, built on the engine makers' guidance and published sources, every one listed at the back. Your owner's manual always has the final word, and the book shows you where to look in it.

No.	Job	Page
01	Why blocks crack, and when your deadline isWhere water hides, and how to read the forecast	p. 7
02	Know your engine and what the shop chargesWhich jobs apply to your outboard or sterndrive	p. 12
03	Fuel, stabilizer and foggingLeave the fuel and the engine ready for months	p. 18
04	Drain the cooling systemEvery drain point, opened and checked	p. 25
05	Oil, filter and gear oilAnd what the old gear oil tells you	p. 32
06	The water pump impellerReplace now, in spring, or not this year	p. 39
07	Batteries, cover, mice and moistureStore it so spring starts clean	p. 44
08	Spring start-upThe order to wake the boat up	p. 51
09	Read the shop invoice, and when to call a proCheck the work before you pay for it	p. 58
10	Stop ifEvery red line from the book on one page	p. 63
11	Printable checklistsOne page for fall, one for spring	p. 66

Page 25 of the guide — p. 25 · The drain chapter opens with every drain point on one diagram.

Page 28 of the guide — p. 28 · The drain-point checklist: opened, water flowed, probed.

Page 67 of the guide — p. 67 · The printable winterizing checklist.

Sheet 4 / 5

From the printable checklist · p. 67

Before the first hard freeze

Stabilizer added; engine run on water to carry it throughChapter 3
Engine oil, filter and gear oil changedChapter 5
Engine fogged as the last running jobChapter 3
Every drain point opened, water seen flowingChapter 4
Battery charged and stored, drive tilted downChapter 7

Tick them off. The full list has 21 lines.

Honest about who this helps.

For you if

You own an outboard or sterndrive under 26 feet.
You can change your own oil, or want to learn.
You want to know what the shop does before you sign.
Your boat can see a freeze, even once.

Not for you if

You run an inboard diesel or a boat over 26 feet.
Your warranty requires dealer service. Check first.

Sheet 5 / 5

Questions owners ask.

Q.1Is this for my exact engine?

It covers outboards and sterndrives under 26 feet, from any maker. Each chapter says what applies to which, and shows you where your own owner's manual has the exact steps for your model. Where the two disagree, your manual wins.

Q.2I'm not very handy. Can I still use it?

Yes. Chapter 9 shows you how to read a shop invoice and what to ask for, so you know the job was done right even if you never pick up a wrench.

Q.3What tools do I need?

Mostly basic hand tools, a drain pan, flush muffs or another water supply, and the fluids your manual calls for. Each chapter lists what that job needs before you start.

Q.4How do I get it?

It's a PDF. After checkout, Gumroad gives you the download right away and emails you a link. It works on any phone, tablet or computer, and prints fine at home.

Q.5Where do the steps come from?

From the engine makers' guidance and published sources. Every source is listed at the back of the book.

Q.6What if it's not for me?

Reply to your Gumroad receipt within 30 days of buying and you get a full refund.

Don't Crack the Block by Dale Brennan, book cover

Before the first hard freeze

Pay once. Do it right this fall.

$9.97One-time · PDF · instant download

74 pages, 9 jobs in the order you do them
A one-page "Stop if" summary of every red line
Printable winterizing and spring start-up checklists
A "My engine" card and a drain-point checklist to fill in

Get the guide · $9.97 →

30day
refund

Not for you? Reply to your Gumroad receipt within 30 days for a full refund. Secure checkout through Gumroad.