How Long Can A Car Sit Unused?

[fognostic]

Except for stabilizer in the gas (and no sense keeping a full tank of it!), other fluids are designed to last 10's of thousands of miles under harsher conditions than a garage. I wouldn't change out other fluids. Over inflate the tires, gas and battery. It also takes some drive time at speed to recharge a near dead battery with the alternator - a quick trip won't do it, so if that is all the battery got, then the battery and alternator are probably just fine.

 

[Jerry1]

Echoing the recommendation to get some good gas and stabilizer in the tank. Take the negative off the battery. I wouldn’t put it on a tender with no one checking on it for the foreseeable future. When it comes time to move it/sell it, charge the battery and deal with it then. If you’re really worried about flat spots, put the vehicle up on jack stands. Personally, I wouldn’t bother. Give some thought to return on investment and include your time in that calculation. I doubt it’s worth doing anything but that’s a subjective decision you’ll have to make.

 

[brett]

You might suggest to her that she pull the car insurance. Change it to fire and theft only.

Easy enough to change it back should at some point she decides to drive it...or have someone else drive it.

We do this every winter on summer car and on our regular driver if we are going to be away for three months or so.

 

[Al18]

Radial tires won't flat spot in months. It takes years for that to happen.

 

[Slim11]

Things that are ment to move will break of they dont. So, yes , things can go bad if the car sits too long.

 

[38Chevy454]

Being inside a garage is a big benefit. Even unheated, being inside minimizes the thermal cycling; as well as weather and critter exposure. As others said, just put a battery maintainer on it and that will keep the battery charged up even with the car itself having a slight usage even when off. If you go and get it started up, overfill the tires some, and fill gas tank with pure gas, not the E10. E10 absorbs water, and is less stable than pure gas for longer periods of time. Drive the car enough so that it gets completely warmed up to normal operating temps. Something like 15-20 miles minimum. I never use any fuel stabilizer, and some of my old cars can sit for 6 months during winter. Just the battery maintainer and they are also in temp controlled garage. Maintainer is designed to stay connected full time.

If the battery in the car is completely dead for long period, it may be damaged and not fully charge up. You can jump start the car and the alternator will keep it running. But a damaged battery can have a surface charge only and not sufficient capacity to restart. It shows as 12-13 volts or so on a voltmeter (fully charged is 13.2 volts), but immediately drops to like 6-8 volts or less under load. So beware of shutting car off without a potential jump start source. Or avoid that risk and just buy a new battery and keep it good condition with the maintainer.

 

[Jerry1]

38Chevy454 is right about using pure gas (no ethanol), but I assumed you may not have access to any. Here is a web site that lists all of the places that sell pure gas. I'm lucky to have a couple stations close to me.

Pure-gas.org - ethanol-free gasoline in the U.S. and Canada

Pure-gas.org is the definitive web site listing stations that sell pure gasoline in the U.S. and Canada.

www.pure-gas.org

 

[Masquernom]

Cars sit for years with no major damage. The things folks have listed here to do are great. It will make it a lot easier when you go to start the car after sitting a long time. However, say the car sits for 2 years, as is, without ever being started or run. More than likely, you can charge the battery, or jumpstart it, and it'll run. May need to drive it till you can fill the gas tank with fresh gas, after which, it will probably run better. See the videos of all the "barn find" autos that start after sitting for years with just a new battery and a squirt of starter fluid.

 

[Al18]

There is no pure gas you can buy in NJ for a car used on public roads. There are other states states with similar availability.

Note gas containing ethanol will go bad much quicker than pure gas. I’ve seen comments that ethanol gas can go bad in 6 months, though find this hard to believe. I’ve seen repair videos showing ethanol gas can crystallize and plug the fuel line.

 

[TheWizard]

There is no pure gas you can buy in NJ for a car used on public roads. There are other states states with similar availability.

Note gas containing ethanol will go bad much quicker than pure gas. I’ve seen comments that ethanol gas can go bad in 6 months, though find this hard to believe. I’ve seen repair videos showing ethanol gas can crystallize and plug the fuel line.

Crystalize, neato!
For the past few decades, I've left 10% ethanol gas in my lawnmower over the winter and my snowblower over the summer with no bad effects.
I must be living dangerously...

 

[freedomatlast]

Same here. I use 10% ethanol gas in everything with no stabilizer. Never an issue for 6 to 9 months.

 

[Jerry1]

There is no pure gas you can buy in NJ for a car used on public roads. There are other states states with similar availability.

The link I provided above shows 5 stations. It might be labeled recreational fuel but there's one location that is at a Sunoco. Unfortunately, the report shows the cost at over $14/gal. Ugh. Pure gas is high here in Michigan, but nothing like that. Closer to $4-$5/gal.

 

[Mark1]

I would probably top off the tank with premium now for two reasons.

1) Premium tends to have a lot less cat cracked gasoline blended into it compared to Regular, due to the lower octane of this stream. Probably not a big deal anymore with the modern specs and hydro treating, but as you clean up this blending stream you lose octane ($) so there is a incentive to minimize the removal of reactive olefins, etc. from this stream. This is the stream that always went bad in the past.

2) The current winter RVP specs will also have more butane and pentanes present, which will help start it up next summer. This might not be a big deal with a modern computer driven engine, but it can't hurt.

Ethanol?
I wouldn't worry about this one. Unless you bought multiple tanks of gasoline to turn over the residual heel, you are likely going to have enough ethanol left in the system to keep water dissolved. I'm not sure I want two phases anyway(?).

 

[Koolau]

For several years, I left my Mazda, OUTSIDE, not touched by human hands for 8 or 9 months at a time. When I returned and started it, I never had to even put a battery charger on it. I just floored the accelerator a couple of times, turned the key and rurrrr, rurrr, rurrr, rurrr, rurrr, vroom, clatter, clatter, clatter (diesel sounds in a gasoline car for 2 or 3 minutes). I'm sure I caused some damage that way, but the car lasted 5 years doing that - then I sold the car to a kid for $100 and he drove it for a year. (Transmission finally went out at 150K).

I'd suggest adding some Lucas oil treatment to it.

 

[Al18]

Jerry1, $14 per gallon is racing gas - doesn’t work with a catalytic converter. The only alternative fuel I’ve seen sold in NJ is off-road diesel.

I’ve left ethanol gas in the lawnmower for 6 months with no problem.

 

[Dash man]

I’ll probably visit next week or two, so I’ll overinflate the tires, put it on a trickle charger battery tender have it jumped started, drive it, and fill gas tank. I may disconnect the battery to prevent whatever might be draining it if it’s not the alternator - I may be able to assess that when I drive it, if she lets me.

Is there any danger leaving a trickle charger battery tender indefinitely with no one around? There isn’t a neighbor to check on it much less drive it, or at least my sister won’t ask for help.

My sister is terminal with metastatic cancer, just moved to assisted living. The car is now sitting in the garage at an empty house. I am her only living family relative, her successor trustee/executor, and sole heir. I don’t care about the money, just trying to help her.

TY

We own a Subaru Outback as a third vehicle and it is not driven for several months each year. We also had battery problems it draining all the time. When we brought it up at the dealership, the guy knew right away. There is a light switch on the inside roof when you open the hatchback. It’s easy to mistakenly turn it to always on by loading things into the back. You don’t realize you hit the switch to always on. It’s hard to realize it’s on in daylight. Drains the battery every time. We put some tape over it to hold it in place.

 

[audreyh1]

Except for stabilizer in the gas (and no sense keeping a full tank of it!), other fluids are designed to last 10's of thousands of miles under harsher conditions than a garage. I wouldn't change out other fluids. Over inflate the tires, gas and battery. It also takes some drive time at speed to recharge a near dead battery with the alternator - a quick trip won't do it, so if that is all the battery got, then the battery and alternator are probably just fine.

Right, much better to use a triple charger - ask me how I know!

 

[Original Wally]

Get a neighbor to do it.

OP's sister won't do that.

 

[Walt34]

Radial tires won't flat spot in months. It takes years for that to happen.

Depends on the tires. The ones on my truck will be thumping in a couple of days sitting in cold weather, a week in hot weather. I'll never buy that brand again.

Getting back to the original question, for long term storage other than a trickle charger/battery tender and some Stabil in the fuel you don't need to do much. I'd also pump up the tires to 8-10 psi higher than specified to allow for slow leakage but other than that I wouldn't do anything else. It might help to leave a note on the steering wheel to adjust tire pressure the next time it is driven.

The worst threat as mentioned is mice, but from 1,200 miles away there isn't much you can do about that other than maybe mothballs and try to seal obvious entry points if you have time during your visit.

 

[pb4uski]

We have two cars the hibernate all winter in a garage. The older one for almost 20 years and another for a few years.

For the older one (2007 Honda CR-V) I just disconnect the negative terminal on the battery. In the spring, I reconnect it and it starts and I drive it out of the garage and let it idle for 15-20 minutes to charge the battery. While that is happening, I pump up the tires since they are usually a little low and the TPMS light is on. I also have to enter an unlock code into the radio. That's all.

For the newer car (2016 Subaru Outback), I put it on a trickle charger over the winter. That's it. It's starts right up and I check the air pressure in the tires.

No fuel stabilizer, but it's not a bad idea IMO.

We do downshift the insurance to comprehensive only and take off the collision and liability. Our umbrella carrier, RLI, is ok with there being no liability coverage while it is hibernating in the garage and not being used. I do put a note on the steering wheel with the name and phone number of the insurance agent saying not to use the car until you have called and put the liability and collision back on. (DS car was in the shop a few years ago and he used the car for a week unbeknownst to us!... No problem with him using it but it needs to be insured!)

I think a car could easily sit a few years as described above with no I'll effects.

 

[Slim11]

For the fuel, yes ethanol and summer blend gas will mess carburetors up if the fuel is old and not treated. Not sure on fuel injectors. I use stable and fuel injection cleaner in fuel that sits in a can. If you get top tier fuel you dont need the cleaner.

 

[Ronstar]

I never put a battery tender on our snowbird vehicle at our Az condo. Had a Jeep Grand Cherokee there for several years when I had a service come and start the car monthly. No problems.

Later I sold the Jeep and moved DW's 2001 Acura to Az. That car did not like AZ summers even with monthly starts. I'd need a new battery every year when we made our first post summer visit in October. We'd arrive, try to start the car but it wouldn't start. I'd call AAA - they'd come and jump it and give me a diagnostic printout to bring to Autozone where I'd present the printout and get a new battery free under warranty.

I should have disconnected the battery after leaving every spring, but I'm not sure that would have helped. Sometimes the battery would swell during the summer - from the heat.

I've read some articles saying not to use battery tenders or trickle chargers on vehicles where nobody is living in the house.

 

[Andre1969]

Newer cars definitely run the battery down faster than old ones. I have a 2023 Dodge Charger I bought back in September of 2023, that only has about 1600 miles on it. Total waste of money from a practical standpoint, but I don't regret it one bit! Only problem is, I was working from home when I bought it, and since retired, and have another vehicle to use, so the Charger just doesn't get driven much. I'd usually try to at least start it every once in awhile, run it up and down the driveway, or "around the block" (which is about 5-6 miles out here in the boonies). Or run it to the grocery store on a nice day. Well, at one point I let the time get away from me, and it sat for a bit over a month, and damn if it didn't drain the battery! It started with a jump pretty easily though, and I make it a point to get in the habit of starting/driving it a bit more often.

In contrast, I also have a '67 Catalina convertible, and over the past winter probably let it sit about 4-5 months without starting, but when I gave it the first start of the year, the battery was fine. The rest of the car was a bit cranky getting it started though. It took a lot of pumping with the gas pedal, and I think I might have even had to take the top off the air cleaner and spray some starting fluid in there.

With the rest of my older cars, I'll disconnect the negative battery cable if they're going to sit for too long, but for some reason this past winter I forgot to, with the Catalina.

I wonder, can a newer car sit for an extended period of time with the battery disconnected? Or would that ultimately cause some kind of computer/memory type problems, with all the modern electronics they have?

 

[WhenIsItTime]

Good question for a Corvette forum. Many low mile examples that sit for months at a time.

I wouldn't be worried about 6+ months at a time causing serious damage. Seems she has already accepted the value is in possession not usage.

Varmint's are a separate issue. Squirrels have cost me a few thousand for a car that sat outside.

 

[Al18]

Ultrasonic rodent repellers are available for $25-$50. The less expensive models plug into an AC outlet, while the more expensive models have a rechargeable battery that lasts for a few months. You could plug one into an outlet in the garage and the other placed under the hood and trunk. Lots of models from Amazon.