How to winterize a motorhome

Andrew Hard

Winterization is a good time to take care of other maintenance tasks. Take a moment to check on the health of your fire extinguishers, smoke alarms, and carbon monoxide leak detectors.

Protecting your motorhome from the cold

A lot of places claim to be “a home away from home,” but few actually walk the walk. A motorhome is quite literally a home you can take with you, offering a greater level of freedom and luxury than most RVs.

Motorhomes aren’t without their drawbacks, though. If they sit idle for long, the freezing temperatures of winter can be particularly tough on them, both on their internal plumbing systems as well as their powertrains. A comprehensive winterization helps you avoid these problems, ensuring your mobile vacation vehicle will stay running for years.

Winterize the plumbing

When we talk about motorhome winterization, the most challenging part is protecting the plumbing system. Dropping temperatures can cause the water inside your motorhome’s plumbing to freeze, which wreaks havoc on the water heater, lines, and tanks. Some owners choose an air compressor to purge water from the system, but adding antifreeze is more effective in preventing issues.

Any time you’re adding antifreeze to a water system, it’s important to bypass or remove any in-line water filters. Antifreeze can damage these filters, which puts the purity of your drinking water at risk.Next, drain the fluid tanks. These include the freshwater tank, the gray water tank, and the black water tank. For the latter two, dispose of the contents at an approved dumping station. These stations have metal water wands available to clean the tanks, but your motorhomes may have a built-in flushing system.Now it’s time to drain the water heater and lines. Drain plugs can be found on the water heater itself, as well as at the low points of the hot and cold lines. Give the heater time to cool down before draining. A 12-volt water pump can expedite the whole process.With the water drained, bypass the water heater, closing it off from water lines that will shortly be carrying antifreeze through them. Depending on the model, your motorhome may have a water heater bypass built-in.At this point, all the water should have completely drained from your motorhome. Turn off all drain lines and faucets in the vehicle, including outdoor showers where available.Use a water pump converter kit to add antifreeze to the system.Activate the water pump to pressurize the system and begin circulating antifreeze.One by one, go to each faucet and turn on the hot water until you start seeing antifreeze coming out. Then, do the same with cold. Repeat these steps at every faucet in the motorhome, including the shower. Flush the toilet several times until you see the colored antifreeze.Turn off the water pump and briefly activate one faucet to release any leftover pressure.Next, find the city water inlet on the vehicle’s exterior. Remove the small protective screen covering the valve and press it with a small screwdriver. When you see antifreeze, you can replace the screen.At this point, antifreeze has been circulated throughout the system. To finish, pour a cup or two of extra antifreeze down each drain and close the faucets.

Protect the engine

Motorhomes have large, powerful engines, but don’t let their brawn fool you — they still need help in the winter months.

Go through your regular maintenance checklist and top off engine oil, transmission fluid, steering fluid, brake fluid, and windshield fluids to prevent moisture accumulation. It’s never a bad idea to take your motorhome to a mechanic to diagnose any issues and check on battery and generator health.

That said, the primary concern for winter storage is fuel. If it sits in a fuel tank for longer than 30 days, it can begin to degrade. This will put unnecessary strain on the mechanical components, gumming up parts and potentially causing damage.

The solution? Fuel stabilizer. These products slow oxidation and chemical breakdown, extending the life of your fuel. With a full gas tank, add the directed amount of fuel stabilizer and run the engine for about five minutes. This will spread the stabilizer throughout the system. When you’re done, remove the batteries and store them in a safe place.

Clean and prep the interior

With the mechanicals sorted, turn your attention to the inside of the motorhome. Prepare the area like you’re doing a thorough spring house cleaning, removing all food, clothes, towels, and bedding. Vacuum any carpet thoroughly and wipe down interior surfaces with an antibacterial cleaner.

At this point, all that’s left is to unplug all the electronics. We recommend leaving refrigerator and cabinet doors open to prevent mold. For more protection, install a dehumidifier in the motorhome’s main area.

Clean the exterior

Winterizing the exterior of a motorhome comes down to a thorough clean. Before you start spraying, however, look for any gaps or broken seals where water could find its way inside. You can close smaller gaps with inexpensive silicone caulking.

Next, wash your motorhome as you normally would. You’ll need a water source, a wash/wax solution, a large scrubbing brush, a squeegee, and microfiber towels if you wish. The wax is the most valuable player as it will keep your paint safe from the elements even as temperatures plummet.

Caring for tires

Motorhomes are big, heavy machines. This puts an incredible amount of pressure on the tires, and if snow piles on top of the vehicle, it exacerbates the problem. If the vehicle sits too long, flat spots can form, weakening the structure of the tire and increasing the risk of blowouts.

A simple solution is to use jack stands to take some of the weight off the tires to prolong their lives. If you don’t have enough stands to raise the entire vehicle, rotate the jacks every few weeks to take at least some of the load off.

Andrew Hard is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.

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