The Central Texas Boater's Guide to Winterization: Why a Mild Winter is No Excuse for a Cracked Engine Block

The High-Stakes Gamble on Lake LBJ:

The Deceptive Beauty of a Texas Autumn

For boat and personal watercraft (PWC) owners in Central Texas, the end of summer doesn't signal an end to life on the water. The beautiful, extended boating season is one of the greatest perks of living in the Highland Lakes region, with warm, sunny days often stretching deep into the fall.¹ This idyllic weather inevitably leads to a question asked at every dock and boat ramp from Lake LBJ to Lake Travis: "Do I really need to winterize my boat in Texas?".² The common perception is that our mild winters make winterization an unnecessary expense, a chore reserved for boaters in northern states who contend with months of snow and ice.²

This perception, however, creates a dangerous sense of complacency. While the boating season is longer, the off-season, however brief, presents a unique and significant threat to your vessel. The purpose of winterization in Texas is not merely about preparing for a deep, prolonged freeze; it's about protecting a major financial investment from the region's notoriously unpredictable cold snaps and the insidious, long-term damage caused by corrosion and fuel degradation during periods of inactivity.³ Skipping this crucial maintenance is a high-stakes gamble against the weather, with your engine block as the collateral.

The Unpredictable Texas Freeze: A Game of Meteorological Roulette

The "mild winter" myth is the single greatest threat to boats in Central Texas. While average daily low temperatures in the Horseshoe Bay area may hover around 40°F in January, the reality of Texas weather is far more volatile.⁵ A sudden, severe cold snap can plunge nighttime temperatures well below freezing, and it only takes a few hours at or below 32°F for catastrophic damage to occur.² The weather patterns are famously "bipolar," capable of swinging from a pleasant 77°F to a destructive 27°F overnight, leaving unprepared boat owners with no time to react.⁵

Historical weather data for the region underscores this unpredictability. While the average first freeze for Llano County is around November 9th and for the broader Dallas-Fort Worth area is November 22nd, these are merely averages.⁹ Freezing temperatures have been recorded as early as October 17th in Llano and October 22nd in other parts of Central Texas.⁹ Relying on a weather forecast to decide when to protect your boat is a losing strategy; by the time a hard freeze is predicted, it's often too late. The most prudent course of action is to schedule winterization proactively at the end of your primary boating season, typically between September and October. This ensures your vessel is protected long before the first unsuspected cold front arrives and before service centers become inundated with last-minute requests.³

Redefining Winterization: It's Not Hibernation, It's Preservation

It is essential for Texas boat owners to reframe the concept of winterization. It is not about putting your boat into a deep hibernation, inaccessible until spring. Instead, it should be viewed as a form of low-cost insurance and essential preventative maintenance that safeguards the vessel's most critical systems.² The process protects against far more than just freeze damage. It is a comprehensive service designed to combat the trifecta of off-season threats: freezing, corrosion, and fuel degradation.³

Proper winterization prevents the buildup of moisture that leads to mold, mildew, and foul odors in the cabin.¹¹ It stabilizes the fuel to prevent the formation of gums and varnish that clog injectors and carburetors.¹³ It protects internal engine components from the rust that can form in a humid, stagnant environment.¹⁴ Ultimately, the greatest benefit of professional winterization is a smooth, trouble-free return to the water when the warm weather returns. It eliminates the frustrating delays and staggering repair bills that can ruin the start of a new boating season, ensuring your investment is ready for adventure the moment you are.² It is a critical component of a responsible, year-round approach to boat ownership.

The Anatomy of a Freeze: What Happens When Water Turns to Ice Inside Your Boat

The Physics of Failure: A Force of Nature Unleashed in Your Engine

The science behind freeze damage is simple and unforgiving. When water transitions to its solid state, ice, its volume expands by approximately 9%.¹⁶ This expansion is not a gentle process; it is an immensely powerful force. Confined within the rigid passages of an engine block or plumbing system, freezing water exerts pressures that can reach tens of thousands of pounds per square inch (PSI), with some estimates as high as 30,000 to 43,000 PSI.¹⁷

To put this force into perspective, a typical cast iron engine block, known for its high compressive strength, is still fundamentally brittle.²⁰ Aluminum blocks, while lighter, have a lower tensile strength and are even less capable of withstanding such internal pressure.²² Neither material is engineered to contain the irresistible force of expanding ice. When water is trapped in the cooling passages of an engine block, exhaust manifold, or heat exchanger, a crack is not a possibility; it is a near-certainty. The abstract threat of a "freeze" becomes a concrete and catastrophic engineering failure.

The Point of No Return: The Cracked Engine Block

The single most common, destructive, and expensive consequence of improper winterization is a cracked engine block.¹⁷ This occurs when a boat owner fails to drain every last drop of water from the engine's cooling system. Older inboard and sterndrive engines are especially vulnerable, as rust flakes and debris can accumulate over time and clog the small drain passages, giving a DIYer a false sense that the block is empty when, in fact, pockets of water remain trapped inside.²³

A common and dangerous myth is that an engine's "freeze plugs" will pop out to save the block. This is incorrect. These are technically "core plugs" or "casting plugs," which are simply capped holes used during the sand-casting process at the foundry. They offer no reliable protection against the immense, uniform pressure of expanding ice and should never be relied upon as a fail-safe.²⁴

A cracked block is a catastrophic engine failure, often rendering the engine irreparable.¹⁶ The financial consequences are staggering. While a skilled owner might be able to replace a long block themselves for a few thousand dollars, a professional, warrantied engine replacement can easily range from $7,000 to over $24,000, depending on the engine model and labor costs.²⁴ This single point of failure can cost more than the entire value of an older boat, all for want of a preventative service that costs a few hundred dollars.

Beyond the Block: A Cascade of System Failures

The engine block is the most dramatic victim of freeze damage, but it is far from the only one. The same destructive principle of expanding ice can wreak havoc on a multitude of other critical and expensive systems throughout your boat or PWC.

• Plumbing and Sanitation Systems: Any system that holds water is at risk. This includes water heaters, plastic holding tanks, water pumps, faucets, shower heads, and livewells. A freeze can burst pipes and crack fittings, leading to extensive water damage inside the boat once the ice thaws.¹²

• Fuel Systems and Phase Separation: Modern ethanol-blended gasoline (E10) presents a unique chemical threat, particularly in the fluctuating temperatures of a Central Texas winter. Ethanol is hygroscopic, meaning it readily absorbs moisture from the air.³² The daily cycle of cool nights and warm days common in the region actively promotes condensation inside a partially filled fuel tank.⁵ As the ethanol absorbs this water, it eventually reaches a saturation point and undergoes "phase separation." At this point, the heavier water-and-ethanol mixture separates from the gasoline and sinks to the bottom of the tank, creating a highly corrosive cocktail that can destroy fuel lines, filters, fuel pumps, injectors, and carburetors from the inside out.¹⁷ This makes proper fuel stabilization not just recommended, but absolutely essential in our climate.

• Batteries: A lead-acid battery that is not fully charged is susceptible to freezing. The electrolyte inside is mostly water, and when it freezes and expands, it can crack the battery's case and permanently damage the internal lead plates, rendering the battery useless.¹¹

• Hull, Bilge, and Through-Hulls: Rainwater that collects in the bilge and cannot drain properly can freeze. The expansion can damage or loosen through-hull fittings, crack the bilge pump housing, or even cause delamination or stress cracks in the hull itself. A compromised through-hull or a failed bilge pump can lead to the boat taking on water, or in a worst-case scenario, sinking.¹²

To provide a clear financial picture, the following table contrasts the potential costs of neglecting winterization with the modest investment in professional service.

Your Complete Texas Boat & PWC Winterization Checklist

The Core Principles of Protection

A thorough winterization process is guided by three fundamental objectives: removing all water from systems where it can freeze, protecting all mechanical and fuel systems from corrosion and degradation, and preparing the entire vessel for a safe, dormant period so it emerges in the spring ready for immediate use.¹⁵ This checklist, based on professional best practices, covers the essential steps for protecting your investment.

Engine & Propulsion System: The Heart of Your Vessel

This is the most critical part of the winterization process, where a small oversight can lead to the most expensive repairs.

• Inboards/Sterndrives: The process begins with flushing the engine's raw water cooling system with fresh water to remove salt, minerals, and debris. Following the flush, the system must be completely drained. This involves opening all petcocks and removing drain plugs on the engine block, exhaust manifolds, and any other coolers. However, the safest and most thorough method is to circulate a non-toxic propylene glycol marine antifreeze through the entire system. This is done by running the engine and introducing the antifreeze mixture until the distinct pink fluid is seen exiting the exhaust. This ensures any small, trapped pockets of water are displaced by the freeze-proof solution.¹²

• Outboards: Outboard winterization starts with flushing the cooling system with fresh water using a set of "ear muffs" connected to a garden hose. While the engine is running, the cylinders should be "fogged" by spraying fogging oil into the air intakes until the engine stalls. This coats the internal metal surfaces—pistons, cylinder walls, and valves—with a protective layer of oil to prevent rust and corrosion. After fogging, the gearcase lubricant (gear lube) should be drained and replaced. It is critical to inspect the old lube for a milky, white appearance, which indicates water intrusion from a failed seal that must be repaired before storage. Finally, the outboard must be stored in the full-down (vertical) position to allow every last drop of water to drain from the powerhead and lower unit.¹⁴

• Oil and Filter Change: It is imperative to change the engine oil and filter before long-term storage, not in the spring. Over a season of use, engine oil accumulates moisture, unburnt fuel, and acidic byproducts of combustion. Leaving this contaminated oil in the engine all winter can lead to corrosion and etching of sensitive internal components like bearings and crankshaft journals.¹²

Fuel System: Preventing Clogs and Corrosion

Modern gasoline, especially ethanol blends, can begin to degrade in as little as 30 days, leaving behind damaging deposits.⁴²

• Stabilize the Fuel: A quality marine-grade fuel stabilizer is a chemical additive that acts as an antioxidant for gasoline. It works by disrupting the chemical reactions that cause fuel to oxidize and break down, preventing the formation of gums, varnish, and other solids that can clog fuel filters, injectors, and carburetor jets.⁴²

• Fill the Tank and Circulate: The proper procedure is to fill the fuel tank to approximately 90-95% capacity. This leaves minimal air space at the top, which significantly reduces the potential for condensation to form as temperatures fluctuate. Add the correct amount of fuel stabilizer to the fresh fuel, and then run the engine for 10 to 15 minutes. This crucial step ensures that the stabilized fuel is circulated throughout the entire system, from the tank to the fuel lines, filters, pumps, and into the engine itself, protecting every component from degradation.¹³

Plumbing & Onboard Systems: A Dry System is a Safe System

Any system on board that uses fresh or raw water must be protected.

• Freshwater Systems: First, drain the freshwater holding tank completely by opening all faucets and running the pump until it sputters. Then, pour several gallons of non-toxic (propylene glycol) marine antifreeze into the empty tank. Turn the pump back on and, one by one, open each faucet (both hot and cold), showerhead, and washdown spigot until the pink antifreeze flows steadily from the outlet. This ensures the entire system, including the pump and all lines, is protected. If the boat is equipped with a water heater, installing a bypass kit is highly recommended. This allows the heater to be drained separately and avoids the need to fill its 6-10 gallon tank with costly antifreeze.³¹

• Raw Water Systems: Systems like air conditioners, livewells, and raw water washdowns must also be winterized. The best method is to close the intake seacock, disconnect the hose, and place it in a bucket of marine antifreeze. Then, run the system's pump until the antifreeze is drawn through and discharged, displacing any trapped water.³¹

Electrical System & Battery Care: Preserving Power for Spring

Batteries are one of the most commonly overlooked items during winterization, often resulting in a dead battery in the spring.

• Remove and Maintain: The best practice for battery care is to fully charge the batteries, then disconnect them (negative cable first) and remove them from the boat. They should be stored in a cool, dry location, off of bare concrete floors which can accelerate discharge. To ensure longevity and a full charge in the spring, connect the batteries to a smart battery tender or trickle charger for the duration of the storage period. This small step maintains the battery's health and prevents the electrolyte from freezing.¹²

Interior & Exterior: Defending Against Moisture, Pests, and UV Rays

Protecting the boat's surfaces and interior spaces is crucial for preventing cosmetic damage and the growth of mold and mildew.

• Interior: The cabin and all storage compartments must be thoroughly cleaned and dried. Remove all food, beverages, linens, life jackets, and any other items that can hold moisture or attract pests. Prop cushions on their edge and leave all lockers and cabinet doors cracked open to promote air circulation. Using moisture-absorbing products, such as DampRid or similar desiccants, can significantly help in controlling humidity and preventing the musty smell of mildew.¹²

• Exterior: Give the entire boat, from the hull to the deck, a final, thorough washing to remove salt, dirt, and grime. Applying a fresh coat of high-quality marine wax provides a crucial protective barrier for the gelcoat, shielding it from UV radiation and preventing oxidation during the off-season.¹⁵

• Covering: A proper cover is essential. Options range from a high-quality, custom-fitted canvas cover to professional shrink-wrapping. Whatever the choice, the cover must be well-supported with a frame to create a steep pitch, preventing snow or rainwater from pooling and potentially collapsing the cover. It must also be properly ventilated with vents to allow air to circulate, which is critical for preventing moisture buildup and mildew growth inside the boat.³⁷

PWC-Specific Protocol: Winterizing Your WaveRunner or Jet Ski

Personal watercraft require a similar but distinct winterization process to protect their high-performance engines and systems.

• Drain and Flush: With the PWC on its trailer, tilt the bow up. Start the engine and run it in short, 30-second bursts, blipping the throttle a few times to expel all trapped water from the exhaust and cooling system.⁵⁴

• Antifreeze: For climates with a hard freeze risk, flushing the system with a 50/50 solution of marine antifreeze and water is recommended. This is done by connecting a hose from a bucket of the solution to the PWC's flush port and running the engine briefly.⁵⁵

• Fuel and Fogging: Fill the fuel tank and add stabilizer, running the engine for a minute to circulate it. Then, spray fogging oil into the air intakes or spark plug holes to coat the engine's internals.⁵⁷

• Final Steps: Lubricate all visible seals, gaskets, and steering/throttle cables. Disconnect and remove the battery for storage on a trickle charger. Finally, it's a wise practice to stuff steel wool or a dryer sheet in the exhaust outlet to deter pests from nesting inside during storage.⁵⁵

Don't Forget the Trailer!

The trailer is an integral part of the boating package and requires its own off-season maintenance.

• Tires and Bearings: Inspect tires for cracks and wear, and inflate them to the recommended pressure to prevent flat spots from developing. This is also the ideal time to inspect and repack the wheel bearings with fresh marine-grade grease to prevent rust and ensure smooth operation next season.⁵⁹

• Frame and Electrical: Wash the trailer frame to remove road grime and salt. Inspect the lights and wiring harness for any damage, and apply dielectric grease to the plug contacts to prevent corrosion.⁶¹

The Professional Advantage: Why Entrust Your Investment to Bay Marine & Sports Center

The DIY Dilemma: A Small Mistake, A Five-Figure Price Tag

For many boat owners, the do-it-yourself approach to winterization seems like a cost-effective option. However, the process is deceptively complex, and the financial risks of a small mistake are enormous.⁴ A single missed drain plug, an air pocket in the cooling system that prevents complete antifreeze circulation, using the wrong type of antifreeze, or failing to identify a clogged passage can lead directly to the catastrophic engine failures the process is meant to prevent.¹² The hidden cost of DIY winterization is the stress and uncertainty that comes with it; the constant worry during every cold snap is a burden that professional service eliminates entirely.⁷

The Hallmarks of an Elite Service Department: Certified, Trained, and Equipped

A professional marine service center offers a level of protection and expertise that cannot be replicated in a driveway. The hallmarks of an elite department include factory-certified technicians who receive continuous, specialized training for the specific engine and systems brands they service, such as Mercury, Volvo Penta, Indmar, and Yamaha.⁶⁷ These technicians work according to manufacturer-specified procedures, using proprietary diagnostic tools to identify underlying issues that a visual inspection might miss.⁶⁷ This adherence to professional standards, often benchmarked by certifications from organizations like the American Boat and Yacht Council (ABYC), ensures that every task is performed correctly, maintaining the vessel's performance, safety, and warranty compliance.⁶⁹

Introducing Bay Marine's Award-Winning Service: Validated Excellence

Choosing a service provider can be a challenge, but third-party validation offers a clear measure of quality. Bay Marine & Sports Center is proud to be recognized as a Boating Industry Top 100 Dealer, one of the most prestigious honors in the North American marine industry.⁷³ This is not a local popularity contest; it is an independent, rigorous evaluation based on a dealership being "unsurpassed in overall business operations, customer service, professionalism, and all the characteristics that go along with them".⁷⁴

This industry accolade is a direct reflection of the very qualities that customers value most. The award validates what boat owners on Lake LBJ already know, as evidenced by a consistent stream of customer testimonials. Clients repeatedly praise the Bay Marine service department for being "incredibly responsive," "prompt, professional, and exceptional," and for going "above and beyond" to solve problems quickly and efficiently.⁷⁷ This powerful combination of industry recognition and real-world customer satisfaction provides a verifiable guarantee of excellence. The Boating Industry award explains why you should trust Bay Marine, and the chorus of satisfied customers confirms that your trust is well-placed.

Convenience Meets Expertise: Right Here on Lake LBJ

Beyond its validated expertise, Bay Marine & Sports Center offers an unparalleled level of convenience that sets it apart. As a full-service, award-winning dealership located directly on the waters of Lake LBJ in Horseshoe Bay, expert help is always just a short cruise away.⁷⁸ This prime location eliminates the significant hassle of loading a boat onto a trailer and transporting it for service—a major pain point for many owners. Furthermore, Bay Marine operates on-the-water service boats, allowing their certified technicians to perform many maintenance and repair tasks, including winterization, directly at the customer's dock. This unique capability combines the highest level of technical expertise with the ultimate in convenience, making proper boat care effortless for the Lake LBJ community.⁶⁷

The following table systematically breaks down the differences between a typical DIY approach and the comprehensive service provided by the professionals at Bay Marine.

Schedule Your Peace of Mind: Don't Wait for the First Freeze Warning

The Time is Now: Beat the Rush and Protect Your Investment

The single smartest and most cost-effective decision a Central Texas boat owner can make at the end of the season is to schedule professional winterization. As the first cold front appears in the forecast, service centers are inundated with calls, creating long waitlists.³ Waiting until the last minute means your boat could be left unprotected during the first, and often most damaging, freeze of the year. By acting now, you not only beat the rush but also secure the peace of mind that comes from knowing your investment is shielded from harm. A professional winterization service is the bridge between a great season on the water and a seamless, trouble-free start to the next one.

Contact Bay Marine & Sports Center's Service Department

Protect your boat or PWC with the proven, award-winning expertise of Bay Marine & Sports Center. Our factory-certified technicians are ready to provide comprehensive winterization services to ensure your vessel is safe, secure, and ready for spring.

• Call Us Today: (830) 598-8763 ⁸⁰

• Visit Our On-the-Water Location: 110 South Wirtz Dam Rd, Horseshoe Bay, TX 78657 ⁷⁸

• Schedule Service Online: Visit our website at baymarine-sc.com to fill out a service request form.

• Service Department Hours:

  • Tuesday - Saturday: 8:00 AM – 5:00 PM

  • Sunday & Monday: Closed ⁷⁹

Conclusion: Your Adventure Awaits

Winterizing your vessel is more than just a maintenance task; it is the first step in preparing for next year's adventures. By entrusting your boat or PWC to the expert team at Bay Marine & Sports Center, you are not simply storing it for the off-season—you are preserving the future memories you will make on the beautiful waters of Lake LBJ. Don't leave it to chance. Schedule your professional winterization service today and rest easy knowing your adventure awaits, fully protected.