Car Storage for a Subaru WRX or STI

Car Storage Starts Past 30 Days

Past 30 days is the line. A weekend or a short trip can borrow a piece of this list. Most of it is for a season, a deployment, or anything long enough for fuel to sour, a battery to sulfate, and a mouse to move in. A garage or a storage unit is the better place. Outside is the hard case: weather, tags, and whoever has the keys.

Top the other fluids off. In a freeze, washer fluid has to be the cold-weather mix. The ordinary blue bottle is often not rated for it, and a frozen tank can split. On an STI, fill the intercooler water-spray tank about halfway with water and nothing else, so ice has room to expand without cracking the tank. If the car has a methanol kit, drain it. Those tanks leak while they sit, including expensive kits with a long list of failsafes.

Fuel and Oil

Store it full. A full tank leaves less air, and less air means less moisture in the fuel system. Draining the tank is the other clean option, and it is a hassle almost nobody should take for a normal layup. Stabilizer goes in before the fill, then the car is driven for a couple of days so the treated fuel reaches the whole system. Stabilizer left in the can, or poured in after the car is already parked, does not treat the lines and the rail.

Pump-gas stabilizer is rated for about a year. Past that, drain the old fuel when you return and fill with fresh. Do not count on a double dose. Bad fuel loses its gasoline smell and starts to smell like turpentine. That smell is a warning, not permission to burn fuel past the bottle’s year.

Change the oil shortly before storage, then drive it. Anti-corrosion additives do nothing while they sit in the pan. Fresh here means about a week beforehand, or within about 500 miles. Oil that is not being used stays serviceable for years, the way it would in the bottle. If it was fresh going into storage, there is no need to change it again before the first start. An immediate change after wake-up is extra credit, not a requirement.

Do not idle it “to keep it healthy”

Do not have someone start it once a month, or every two weeks, and let it idle. Ten or 15 minutes does not bring the engine to full temperature, even when the gauge looks normal. Water stays in the exhaust and rusts it from the inside. Short running also washes fuel into the oil. If the drive is not 10 miles or more, it is not helping the car. Revving it in the bay is the same mistake. If storage insurance means the car cannot be driven, leave it prepped and parked.

Short errands are a different problem from a parked car. A car used only for those trips can throw a check-engine light when the oil is overdue by time, even with only about 1,500 miles on that oil. Degraded oil can clog a passage, and a couple of flushes with fresh oil have cleared it. That is oil still in service on cold, short runs. Oil that was changed and then the car was parked can stay.

The Battery

Plan on a dead battery and soft tires. A battery can be dead in two weeks, or still crank after six months, including after a few months sitting in the cold. Plan for the bad day. A factory battery that has been left flat often will not come back.

What kills a lead-acid battery in storage is a long discharge. The chemistry self-discharges, and anything still connected adds a small draw, including the clock. A battery left flat sulfates. A discharged battery can also freeze and crack. Kept full on a low-current maintainer that does not boil the water out, a lead-acid battery can last about 10–15 years. Pulling the battery, or at least disconnecting it, stops the car’s draw. Removal is the surer one, because a cable cannot fall back on the post. Set it on a dry, non-conductive surface. If someone will be driving the car, the battery stays in.

A continuous cheap trickle left for months can start a fire, explode the battery, or cook it. Use a maintainer that charges and then stops. A solar panel on the dash only works when the accessory socket stays powered. On a 2006 Impreza, key-off kills that socket, so a panel plugged in there does nothing. Dome lights get switched off. Pulling the dome bulb stops a door or a glovebox left ajar from flattening the battery while someone hunts for a scraper.

Tires and Jack Stands

Modern tires can flat-spot, and the spot is temporary. It shows up most on old nylon-cord tires, which are uncommon now. Air them, drive them at moderate speed for a few miles, and the thump goes away as the tire warms. Taking the wheels off, or parking on jack stands, is not required to save the tires. Wheels left on through a 4–5 month winter, overinflated, come back fine.

Add about 5–8 psi over normal so a slow leak is less likely to unseat the bead. About 10–12 psi over the door sticker, set once the tires are parked and cool, is the other figure in use. Do not average those into a third number. Have a way to air the tires when you come back, because they will be down. Tires stored off the car can be stacked on their sides. Unmounted tires are better standing upright so they do not distort. Mounted tires hold their shape from air pressure either way. If they are off the car, keep them out of the weather and check the pressure before they go back on.

Jack stands hang the suspension on the bushings in a position it does not see on the ground. If the building floods or catches fire, a car in the air cannot be rolled out. Raising it also does not stop mice. A nest can still end up in the passenger seat. Judge the fire and flood risk where the car actually sits. If you might need to move it, leave it on its tires.

Surface rust on the rotors is normal after a sit. A car left about a month outside can need the rotors surfaced. Driving it is what keeps that rust from setting in. Leave the transmission in neutral. Do not leave the clutch pedal held down so the disc stays off the flywheel. That keeps the hydraulic system under pressure for months, and a clutch does not stick to the flywheel from sitting. On a long garage sit you can chock the wheels and leave the parking brake off so the brakes are not clamped the whole time. That is optional.

Moisture, Pests, and Covers

Close the windows and the doors. Anything bigger than a dime is an entrance: the tailpipe, the intake, holes in the fender liners, and whatever a flashlight shows underneath. Tall grass and weeds against the rocker are a ladder into the engine bay. Cover the tailpipe well, with several layers, and do the intake the same way. A rubber ball sized to the pipe, with a rope through it so it can be pulled, does the same job. Traps and a deterrent spray around the garage help. They do not replace the plugs.

Inside, the worries are moisture and smell. Desiccant packs help, and some of them change from pink when moist to blue when dry. If someone is checking the car, many of those packs can be dried in an oven and used again. A tray of plain charcoal does the same cheap job. Not the self-lighting kind. This step is optional. It is not what saves the car.

A sealed car bag or jacket is an indoor tool, used with desiccant. Wind will pick a bag up outdoors and sand the paint. For a 6–12 month indoor sit, put pans of fresh unscented clay litter under the car inside the bag, wash the car a few days early so the water can leave, run the defroster on recirculate for about 30 minutes, let it cool overnight, and bag it on a drier day. Weatherstripping holds water until the doors are opened and shut. The desiccant can only take so much. That routine is for a sealed bag, not for a winter in a dry garage.

Paint wants a real detail and a wax chosen for how long it lasts, not for how hard it shines the first weekend. Indoors, a cover that will not scratch where it touches the paint is the usual yes. Outdoors, a cover flapping for six months or a year can be harder on the paint than pollen and dirt. There is no single best cover fabric. Indoors, dust is the job. Outdoors, think about the fabric moving against the clear coat before you buy one.

Insurance and a Caretaker

Call the insurance company well before the car goes away. Some policies will drop to a storage level of coverage, and they may want an odometer reading first. Call again the day it comes out, before it is driven. Storage-only coverage can mean the car cannot legally be driven. That removes the only useful exercise, which is a real drive. If the policy forbids driving, do not have someone idle it anyway.

Registration, inspection, and plates have to stay current for the whole sit. Outside, an expired tag is how a car gets towed without a conversation. If someone else has to handle plates or an inspection, a limited power of attorney can name exactly those jobs. Talk to a lawyer, or use a real limited form, so the helper cannot sell the car. If another person will drive it, look at a valid license, confirm their own valid insurance, and write down what they may use the car for. The car takes premium. Say that in the note, and on the dash, or the helpful tank of regular is the welcome-home present.

A caretaker who can only start the car and let it run is not a caretaker you need. Either they can take it for 10 miles or more, keep the tank full, and watch tire pressure, or the car should sit still with the prep already done.

Waking It Up

For a normal layup, start it. Cranking with the fuel and ignition disabled, the way you would prime a fresh engine, is not worth doing. A pre-oiler that holds oil pressure the whole time you are gone is the expensive version of the same idea, and it is not the plan for a season. Fog the cylinders only for a multi-year sit. For a year or less, leave the spark plugs in.

1. Read the dash note. Pull the tailpipe plug, the intake cover, the desiccant, and the cover or bag before anything else.
2. Air the tires and fit the battery. Charge it, or install a known-good one. If you are jumping a battery that has been flat, leave the cables on for about 10–15 minutes before you crank.
3. Start it the normal way. A clutch start is the last resort. Third or fourth is easier than first, and it is still the backup, not the plan.
4. Expect a clunk as you pull away. That is one or more differentials breaking free after sitting. It feels like you ran over a chunk of pavement.
5. Drive about 15 minutes with no boost. Wait until it is fully hot before you use it hard. If the oil was fresh when it was parked, a new oil change can wait.

For a sit measured in years rather than a season, pull the battery, use a moisture bag indoors, and drain the fuel if it is past the stabilizer’s rated year. Coolant, gear oil, and brake fluid do not get a special storage change. Top them off before you park.

FAQ

When does car storage prep actually matter?

Past 30 days. Shorter sits can use pieces of the list. The full routine is for a season or longer.

Should someone start it every week?

No, not to idle. A drive of 10 miles or more is the only exercise that counts. Otherwise leave it parked.

Will the battery be dead?

Plan on it. A battery can fail in two weeks or still start after six months. A maintainer that shuts itself off is how you avoid finding out.

Do I change the oil before the first start?

Not if it was fresh when you parked it, within about a week or about 500 miles. Unused oil does not go stale the way fuel does.

Should it go on jack stands so the tires do not flat-spot?

No. A flat spot on a modern tire comes out after a few moderate miles. Stands hang the bushings and leave you unable to roll the car out.

Is an outdoor car cover a good idea?

Usually no. Months of fabric moving on the paint can be worse than dirt. Indoors, a cover that will not scratch is reasonable. No single fabric is the winner.