How often should you drive a modern car to keep it in good working order?

I have a friend who lives in Boston who plans on keeping her car at an off-site parking lot/garage. She won’t be driving it much on a normal basis. I assume that letting it sit for a while isn’t good for the car but how often should she drive it? I was thinking once a week but that’s largely a guess on anecdotal evidence.

Facts -

car: ~ 2015 Subaru Outback
city: Boston (so rain, snow, and ice)
parking condition: unknown but probably uncovered (i.e. no roof). How much does that matter?

Anything else to think about? E.g. should it be driven on the highway?

No exact answer. Once a week is a reasonable estimate, and it should be driven at least 15 minutes or longer in that time.

Winter will be hard on the battery so as it gets old it may not start. She would probably rely more on time estimates for oil changes rather than mileage.

Once every week or two is the general advice I have always heard.

You don’t need to drive it on the highway but you do need to drive it long enough for it to completely get up to its normal operating temperature.

When a car sits for a while, water vapor in the air inside the engine will condense with temperature changes, so you’ll end up with a bit of water in the engine oil. Also, one of the products of gasoline combustion is water, so if you don’t get the engine and the exhaust up to their full operating temperature, you’ll end up with a bit of water in the exhaust system. Once the car is fully warmed up, any water inside the engine or in the exhaust will get flashed into steam and expelled.

Cars that are rarely driven, like only going to the grocery store once a week, often end up with the exhaust systems prematurely rusting out because they never get up to their full operating temperature.

Make sure that you use the brakes, which you might not do much of if all you do is hop on the highway and go up and down the road a bit. When brakes aren’t used, you’ll get surface rust on the rotors and the calipers can rust a bit as well. The surface rust on the rotors isn’t that big of a deal because that will get scraped off fairly quickly once you drive the car around and use the brakes for a bit. But if the calipers get too rusty they’ll stick, and you can end up with every uneven brake wear and possibly an expensive brake repair job to fix them.

Most cars can sit a week or two without any issues. Any longer than that, and a lot of modern cars will drain the battery, possibly to the point of permanent damage.

If you don’t drive the car at all for a long time, rubber seals will dry out, the brakes will rust in place, the battery will die, the gas in the tank will go bad (happens faster with blended fuels), the oil will get crappy, and the tires will develop flat spots. In my experience, the flat spots on the tires will usually sort themselves out after a couple of weeks of driving. If you aren’t going to drive the car for a couple of months, you need to do something about all of these (jack the car up so the weight isn’t on the tires, and stabilizer to the gas, change the oil as soon as you start the car again, disconnect the battery or put it on a tender, etc).

When I spent two months away in 1997, my then seven year old Honda sat in a garage (somewhat heated) for the whole time. I had asked my wife to move it to the driveway and at least idle it once a week, but she didn’t. She hadn’t driven in years and didn’t want to (and finally gave up her licence last summer). I was apprehensive, but the car started right up and I drove it around a while and it seemed fine. It lasted another ten years and it was rust that finally did it in. Incidentally, the instruction manual that came with the car said that the car was engineered to be driven every day and once a week was inadvisable. Tough, I said to myself. I probably drive it once a week to the market, a mile each way, and once every other week to a concert downtown, four miles each way and that’s. The car I bought in 2007 has less than 29,000 km on it.

A friend originally from California has never driven in snow and parks his car permanently all winter every winter. Indoor on blocks. I guess it works.

My Prius recently sat for three months, outside in Southern California. I asked my wife to drive it every week, but I’m pretty sure she didn’t. I started it once during a brief trip home. It runs the same as it always has.

Mr.Wrekker has a farm truck and a jeep he only uses during hunting season. It seems to me it’s a big ordeal to get them up and running every year. He had a big battery problem this time. He charged it up but it wouldn’t hold. He went and got a new battery and drove off to the deer camp. I guess he made it, i haven’t heard from him. Of course I don’t think it could be considered modern, really.

Bedawrek is correct in pointing out the main, potentially only issue you need worry about - they battery. The only rational approach is to affix a float charger and forget about it for as long as needed/reasonable. Months at a time would not be unreasonable. I once stored an S15 pickup that way 4 years, albeit in a garage, no problem.

If A/C power is not available, a good alternative is to simply remove the battery, take it home, do the float charger thing there, providing R&R’ing the battery is not an obstacle in itself. Check with a Subaru dealer to make sure there is not some hidden computerized hazard with leaving it de-energized.

yep. if a car is going to sit for a long time in the cold, either keep the battery on a “battery tender” or pull it and bring it inside. the freeze point of a lead-acid battery’s electrolyte depends mightily on the battery state of charge. Fully charged, the electrolyte won’t freeze until something like -90F. 60% charged, it can freeze at -16F. 20% charge, it’ll freeze at 19F. and once it freezes, it’s likely the plates are damaged and the battery is junk.

Anywhere from once a week to once a month.

Contrary to popular myth, starting and running it at all in any sort of storage scenario is generally a BAD idea. If you are going to USE/DRIVE it for long enough to get fully warmed up and the battery re-charged, OK. Just starting it for a brief warm-up will exacerbate and hasten related problems If it is not run long enough to fully recharge the battery and drive out condensation.

It’s kind of a waste of fuel, too.

I have 2 summertime cars that get a full tank of fuel and go on trickle chargers in the fall, then in the spring, they get an oil change for a summer of driving. Been doing it for years with no signs of problems.

The Chevy Volt is a plug-in hybrid with a 40+ mile battery range, so many owners go for weeks or months without needing the gasoline engine. But if you go for 6 weeks without running the engine, it will go into “battery maintenance mode” and run the engine for 10-15 minutes. They say it’s to use up the stale gas in the fuel line. So GM engineers evidently think their engines should be run at least once every 6 weeks.

Also, if you go for a year without adding gas, it will switch to engine power mode and use up all the old gas. Even though the Volt has sealed fuel tanks to help preserve the gas.

I’m always a bit nervous when we return from two weeks of vacation in January and it has been very cold. My Jeep Wrangler(s) have started every time, though.

I have two vehicles and am only one driver, and even before my spouse passed away he was driving less and less so one or the other would sit for extended periods of time. so I’ve been dealing with this for a couple years now. My truck is 19 years old and the car 16, so on the elderly side for what they are, but both are reliable - i.e. start easily even in winter, minimal breakdowns.

I make a point of driving each one at least once a week. I try for at least 20-30 minutes. (Most weeks I do even better than that, that’s a minimum)

I change the oil based on time, not mileage

Gas line dryer in the winter is a good idea. So is keeping the gas tank relatively full. If you don’t keep the tank at least half full DEFINITELY use gas line dryer if you live in a climate that gets rain/snow/sleet.

Keep an eye on the battery. A new battery will hold a charge longer/better than an old one. I changed the battery in my truck this fall before I strictly had to because of a decline in efficiency - knowing it would sit for up to a week at a time in winter I didn’t want to risk having a marginal battery not willing to start in typical winter weather for my area.

In truth, all of the above is conservative - once, because of lack of funds and needed repairs, the truck sat two months. It still started up on the first try (although I’ll point out that was in summer, in warm weather). As noted, modern cars can probably go a month or six weeks between running the engine. But one of the reasons my vehicles have reached their current ages and are still running without frequent problems is that they have been cared for.

I’ll underline that simply idling for ten minutes in a driveway isn’t really what’s meant by “running the engine”. As others have said, you need at least 15-20 minutes, get the engine temp up (which can be nothing more than a wild guess if all you have is “idiot lights” on the dash). Yes, sometimes that means going for a 15-20 minute drive without a set destination but rather a “mission profile” of “drive for 15-20 minutes, get up to 40-50 mph for at least half of it”. Sure, it burns gas but it is cheaper than repairing the damage rust and water in the mechanical bits can do.

If the car is going to sit for months, like, the entire winter, it might be better to “winterize” it or, to put it another way, set it up for long-term storage. I’ve never done that, so I won’t attempt to comment further on that.

Some people go to great lengths to winterize their vehicles, including adding fuel stabilizer to the tank, and even using fogging oil.

All of which strikes me as wretched overkill. In my experience, such extensive “winterizing” is not required. Every year I park my motorcycle for the Michigan winter, and the only prep I do is filling the fuel tank (to minimize diurnal breathing) and hooking up a Battery Tender to keep the battery charged. My last motorcycle went well over 100,000 miles with this treatment, no problems; my current motorcycle is still doing fine with about half that mileage, and I’m not expecting any storage-related issues in the future.

I would not expect cars to be any different.

Tires do seem to vary. My wife and I take an annual vacation that lasts over two weeks, during which we park my wife’s car at the airport. Upon returning, the brake rotors are pretty crusty (takes a few miles of unpleasant noises to scrape it all off), and the tires have major flat spots. Meanwhile, my car sits at home in the garage for the same time period. The brake rotors on my car are rust-free upon return - no surprise, since it’s in the garage instead of outdoors for that time period. But interestingly, the tires on my car don’t seem to develop flat spots. :confused: In any event, no big deal; the flat spots on my wife’s tires fade away after a few minutes of driving.

What I’m seeing so far is a lot of people saying “Of course it’s necessary; I make sure to do it all the time and I haven’t had problems”, and a few people saying “I don’t think it’s necessary; I never do it and I don’t have problems”. Are we sure that this isn’t just tiger repellent? Has anyone ever run controlled tests, with modern vehicles, comparing regularly-driven ones with ones that are just left to sit?

Another bit of anecdotal data to add - I have many friends with racecars that are actively run every few weeks from May-September but sit out the winter in storage. They don’t get a lot of miles but they are hard miles.

Clearly, a modern car isn’t going to dissolve into a pile of goo if left sitting for awhile.
If the car is up on stands, and the tires are off the ground, the only thing that will prevent the car from starting and being able to be driven after many months of sitting is the condition of the battery, and the gasoline. Using a solar charger (like I do on my project truck) will let it start right up after 2 months of sitting. I’d guess that gasoline would be OK even after a year, but it might take a bottle of dry-gas to help it start after that length of time. The idea that the oil will turn into corrosive sludge is an exaggeration - if the car is sitting, the oil is going to be in much better shape than if the car is started and driven around the block and then parked again, over and over.

Here’s everything the Car Talk guys wrote about maintaining cars in long-term storage.

I left my Honda Civic parked outside at a self-storage lot for two years while I was in Germany. I disconnected the battery and set the parking brake. It started right up when jumped, but the brakes had stuck to the rotors because setting the parking brake was a stupid idea. It otherwise ran fine, even with old gasoline.

On my last assignment to Mexico, I’d driven my Continental there. I left it mostly parked in the parking garage (because I had the use of a company car). In this case, I’d installed a battery quick connect to make it easy to reconnect the battery. I usually took it out every couple of months, typically if I were working a Saturday so that “hoy no circula” wouldn’t apply to me. The gasoline was 1.5 years old when I finally started the return trip back to Michigan.

Most recently, I kept my Expedition in my home’s garage for five years while I was in China, with the battery disconnected. Because I let the plates and insurance lapse, the most I would do it take it out of the garage during home leave, let it get completely warm, and take a very careful trip around my neighborhood just to get everything else spinning. It started up and drove perfectly fine when I repatriated. In fact, I drove it to work today because I have to fetch my camper from the axle shop after work today.

In all cases, the key is to disconnect the battery, and add fresh gasoline as soon as you can!