Some related topics:

How to maintain a sometimes-used vehicle?

How long does it take for gas to go bad?

The first related topic addresses preparing a vehicle for long-term disuse, and maintaining it during those periods. The second related topic addresses one of the effects of a long-term inactivity on a vehicle.

Here, I'm looking to cover what should be done after the fact. Say a vehicle has been parked for several months and was neither prepared for this, nor maintained during that period.

What particular adverse effects of long-term un-maintained storage should one be aware of when trying to revive a car in this situation? What things should be checked or touched on before starting the car? What measures can be taken at this point to prevent further damage to the vehicle during its first re-start, and facilitate bringing it back to a safe and healthy operational status?

UPDATE: Good news. The car ('96 Lincoln Mark VIII) that prompted me to ask this question has started successfully. It had been sitting for probably 6-9 months without any preparation. The battery is definitely toast, and the engine really doesn't like the condition of the gas, but it started pretty well and got around the block a few times.

For the first start, I swapped in the battery from my '94 Jeep Grand Cherokee. Then, after pulling the Mark VIII out to where I could reach it with jumper cables, I put the original battery back in. It's had to be jump-started every time since.

The engine is running pretty rough, and I've got a constant (and occasionally flashing) CEL going. It also turns out that I've got about 3/4 of a tank to burn through before it'll get any really good gas. I threw in a couple gallons of premium (91 octane around here) and a can of SeaFoam to hopefully help though.

Thanks for the tips, guys!

  • 6
    In my area, "idle" means the engine is running at minimum speed. You may mean "stored".
    – Jay Bazuzi
    Commented Mar 9, 2011 at 3:08
  • 2
    @Jay - I was sort of wondering if that might cause some confusion, but figured the fairly clear context would resolve that.
    – Iszi
    Commented Mar 9, 2011 at 4:03
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    Thinking about the guidance to ask questions for problems you're really facing, please tell us how long the vehicle has been stored, the climate, whether it was under a roof, and what steps were taken to put it away properly.
    – Jay Bazuzi
    Commented Mar 12, 2011 at 3:26
  • 1
    @JayBazuzi - I'm hoping to leave this question open enough to be useful for many others, but in this particular case the vehicle has been sitting outside in Florida for about 9 months (June - March). It was not prepared for this, and probably has 1/4 tank or less of gas if I recall correctly.
    – Iszi
    Commented Mar 12, 2011 at 15:37
  • thankyou for your advice on prepping an engine not started or run for 12 years. Commented Feb 12, 2017 at 5:31

4 Answers 4

  • If you have one available, use a trickle-charger to bring the battery back up slowly, instead of jump-starting it.
  • Check the tires. They are probably pretty low at this point. See if they are dry rotted (all cracked and ready to wear quickly).
  • Check all of the fluids in the typical way. Note that it's okay if the oil shows a little low since it's not warm yet.
  • Check the serpentine belt - like the tires, it is rubber and susceptible to dry rot.
  • If there is room in the fuel tank, I'd go ahead and fill it up sooner rather than later to get some fresh fuel mixed in with the old.
  • Keep a baseball bat handy for the pissed raccoon that just lost its house. Hmm, that's actually a good point - if you live out in the boonies, bang around on stuff to scare off the critters. It's a pain to clean animal parts off the engine fan.
  • Start it up and see how it drives. Take it easy while it warms up.
  • I'd drive it around for awhile and when it's nice and hot take it to the gas station as mentioned earlier. Then check your warm levels (engine oil and transmission oil) and check again for any leaks now that it's been running for awhile.
  • I'd probably go ahead and change the engine oil and whatever else is due base on the usual time/mileage.

All in all, nothing particularly different than what should be happening at any normal oil change, since you are talking about months and not years.


My dad actually brought back a truck (big type semi) from a condition like this - it had a manual transmission but we did the maintenance stuff, replace belts, oil, lubricants etc. THEN we hooked up a chain, put it in gear and proceeded to drag it (tow) (in gear) for a while (a half hour to an hour?) at a slow speed - this allowed the engine to be fully lubricated prior to actually attempting to start it. NOTE: this had been parked for YEARS (20?) and the engine was actually frozen (pistons locked in due to corrosion/old dry lube etc.) so we had a bit more than a casual amount of rubber and stuff to replace.

We removed the pan and scraped etc. old gunk out used a light weight oil, then changed it after just a few hours of initial operation (with filter change) to help clean it.

  • Interesting! I have a motorcycle that has been sitting for a few years, before starting it, I'll push it down the driveway and let out the clutch a few times to turn the engine over before trying to start it.
    – travis
    Commented Mar 11, 2011 at 17:43
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    @travis I'm not sure what pushing would accomplish. Cam manufacturers recommend getting rpms to above 2000 asap. Don't dilly. You need to get the oil pump pumping oil to the top quickly, or you will ruin a cam. If you can, remove a valve adjustment cap and add some oil.
    – Randy
    Commented Aug 7, 2013 at 16:56
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    @Randy is correct, and the reasoning behind it is that the presence of oil is not what lubricates the engine. Oil at pressure actually creates a film that prevents the parts from fully coming together, but still allows them to act on each other. You won't have any pressure while pushing. You can read on this in detail here: bobistheoilguy.com/motor-oil-101 it's an amazing site for how your oil really works from a doctor who is also obsessed with motor oil. It takes all kinds. But his site has incredible information on it and is accepted as "the" motor oil info site.
    – cdunn
    Commented Jan 15, 2016 at 15:08
  • 1
    Agreed, perhaps I was not super clear - we used the "drag around" to actually drive the engine at speed, thus after our initial manual lubrication oil was being pumped and our main focus was to loosen the accumulated deposits and remove those prior to adding full power. Once we got it in a cleaner state, we added fuel to begin self power Commented Jan 15, 2016 at 15:17
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    What I've done when bringing an engine "out of retirement" is to remove the plugs, spray some WD-40 (any light oil would probably work) into the cylinders, wait five minutes to let it work its way down to the rings, then crank the engine (with the plugs still out) until I see good oil pressure (usually just a few seconds). Then I replace the plugs and start the engine normally.
    – TMN
    Commented Apr 15, 2016 at 14:49

If the gas wasn't treated, then it will be broken down. That means a gummy varnish substance everywhere, but most critically in the carburetor/fuel injector. That may stop the engine from starting, or at least make it run poorly.

If you can get the engine to start, you can use a product like Sea Foam (http://www.seafoamsales.com/). Their instructions have you pour it in 3 different places, but a shortcut is just to pour the whole thing in the gas tank. The 3-places-method probably works better, but it depends on how serious you are, and whether you plan to overhaul something soon. Regular gas preservative can also help, but my sense is that Sea Foam is a little better for cleaning up a mess, while gas preservative is better for preventing one.

If the gas is really bad, you'll have to get rid of it. I've never seen a great way to get rid of old, stale gas. Here are some not-great ways I've seen:

  • mix it with good gas and run it through another engine, say a lawnmower.
  • pour it on weeds in the driveway.
  • pour it in a bucket and light it.
  • pour it on a brush pile you want to burn.

Gas is explosive, pollutes groundwater, evaporates to pollute the air, and soaks through your skin. So, hard stuff to handle.

  • 1
    Thanks for the information. Would it be beneficial to add SeaFoam and a few gallons of fresh gas pre-emptively? Or should the SeaFoam only be used after a successful engine start?
    – Iszi
    Commented Mar 12, 2011 at 15:39
  • 1
    @Iszi: Sea Foam in the tank won't do much to help the engine start. If gum is causing it to run roughly, Sea Foam can clear out the gum. If it's too gummed to start, you'll need to do something more drastic - overhaul the carburetor, for example.
    – Jay Bazuzi
    Commented Mar 12, 2011 at 21:52
  • 1
    I think what I'm trying to get at is: Will SeaFoam and new gas, added pre-emptively, help prevent additional gum from the old gas from building up on the parts? On the other hand, could the SeaFoam make the "first start" more difficult on the engine?
    – Iszi
    Commented Mar 16, 2011 at 20:46
  • 2
    If you take your car to a shop, they should be able to pump the old gas out of the tank and put some fresh gas in. They may charge you for "material disposal", but they at least have the facilities to take care of it properly.
    – TMN
    Commented Apr 15, 2016 at 14:43

Hi to those starting engines which have been sitting "idle" for more than three months. We recently started a 190e Benz which had not been started for more than 6 months.

First step was to check condition and level of all fluids (engine oil, trans fluid, coolant, power steering, brake fluid and battery acid). We then checked drive belts and battery terminals for tightness, and removed spark plugs, cleaned them (had to replace one with cracked insulator) and squirted WD-40 and RP 7 (spray lubricants) into the cylinders whilst spark plugs were removed. It was then decided to drizzle a little oil into the top of the engine via the oil filler cap and a short piece of clear plastic tubing.

We added fresh fuel to a nearly empty tank and after coaxing a hibernating fuel pump back into action with a few bumps from a rubber hammer ! The exhilaration as this beautiful little engine burst into life emitting a familiar crackle from the albeit smokey exhaust before settling into its idle. Enjoy the thrill, Kit from Down Under.

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