So I drive a '97 Subaru Legacy with about 200,000 miles on it. Still runs like a charm, never gives me any trouble. Had the brakes, rotors, and calipers all replaced recently, tightened the power steering belt, replaced a tire...that's it.

But I know this can't go on forever. But I also don't understand why.

I can keep making $100-$800 fixes once or twice a year no trouble. That's fine. To the best of my knowledge, the only thing that could brake and be beyond my ability to repair is "the engine" or "the transmission," either of which costs thousands.

So this is a fairly open question-- how can I avoid deathly component breakdowns? What should I look out for, what precautions should I take, what should I have greased or oiled or replaced or shined up before it's too late, what can I do to prolong the life of the mysterious metal object known as "the engine," and also "the transmission"? Past the 200,000 mile mark, what's going to be problematic in the near future? And how much longer do I have, on estimate?

All advice is welcome. During college, anything beats buying a new car.

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    I feel like I'm consulting the medical team on options for my dying grandfather. Jun 16, 2012 at 7:41
  • +1. I have similar `97 car (Skoda) - so far maintaining costs are cheaper than buying and maintaining any new car by times. So I would like to know (maybe that can be a part of you question?) - how to detect the point when old car should be scraped in favor of buying new(er) one (in pure practical reasons!).
    – Kromster
    Jun 18, 2012 at 5:12
  • Consider that $800 twice a year is substantially less than the depreciation on a new car.
    – Criggie
    Feb 16, 2020 at 18:51

5 Answers 5


Some reasons that old cars may not be able to be supported indefinitely are:

  • Rust. If you get rust in areas that are hard to reach and compromise the integrity/safety of the vehicle, it may be cheaper to buy a new car than pay the massive labor for extensive rust repairs. These days labor rates are insanely high, the killer is the disassembly/reassembly (Got a quote to paint my car for $8000 simply due to the labor of pulling the body parts off for paint! Actual paint cost & labor was only about 10% of the total cost!).

  • Parts availability. When your power steering rack (just an example, could be any part) breaks in a way that requires a unit replacement you may find that there are none available. When I had a caliper irreparably seize up in my car (cooked it beyond being able to have the seals replaced), it took 2 weeks to find a replacement! None available new. None available in the dealer network. No aftermarket replacements/refurbs available. None available in any of the junkyards we tried. Finally found one in a warehouse out in Cali...

The engine/transmission thing is the least of my concerns about car longevity. Even if you spend $4000 getting an engine, it's still way cheaper than buying a new car... :-)

  • Just curious, what model(s) was that caliper for?
    – MDMoore313
    Dec 23, 2013 at 13:19
  • 1991/2 Toyota MR2 Turbo caliper. I've now got a similar situation with my 1995 Mitsubishi Eclipse GSX (with factory rear LSD). I had a rear wheel bearing go bad, which is not normally too tricky. However, it's been on a lift for nearly 3 months while we're trying to source usable axle cups (everything was so badly rusted that the originals are no longer usable). Dec 23, 2013 at 15:59
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    @BrianKnoblauch revisiting this four years later...you were right. Rust killed it. Rear wheelwells rusted out completely, to the point that there was a small hole in the trunk. Repair quotes were insane. I was very sad. Such a god damned shame, because everything else about the car was functioning flawlessly, even as I was approaching 300k miles. Jun 22, 2016 at 17:51

I don't consider a 15 year old car to be that old! Regular maintenance is the key. Change the oil etc regularly (go by the service schedule), and use a good quality oil and filters. Change the transmission fluid, make sure the belts get done on schedule, etc.

When I was running cars of that age as my everyday transport, it was terminal rot that killed them, not mechanical failure. Rust can become very expensive to fix, but you might be lucky and live in an area where that is less of an issue.

Legacys are pretty solid from what I've seen. If you look after it, you should have a good couple more years out of it - it should at least keep going until you've finished studying...

  • Rust around wheel arches is one Subaru problem so keep an eye on these areas.
    – Rory Alsop
    Jun 19, 2012 at 11:36
  • I've already got that rust as of the past year! It worries me but I don't know what to do about it. Jul 25, 2012 at 14:48

The key to running an older vehicle is maintenance. That frequently means preventative maintenance, so you change the oil as required as opposed to letting it sit.

Garaging older vehicles helps them continue too - a modern car can shrug off a snowstorm and live outside fine, but older cars sulk.

Parts availability counts - I have a 1973 landrover, older than me by three years. I have a local motor in mine, a Holden 202 straight six, and I bought the whole reconditioned short block for less than the cost of a landrover starter motor.

Usage is important. Mine's a 4WD and has a lot more moving parts like transfer case and front drivetrain. Pootling around in 2WD doesn't move the front diff so it only gets splash lubed. Driving mine in 4WD every couple months helps keep it running right.

When does it need replacing? When the cost of a repair is more than the cost of a replacement vehicle. At that point you can choose to part the vehicle out and recover some money that way, or sell it as a parts donor.

If you find that the little repairs and running costs add up, it may be financially responsible to replace it with a more efficient vehicle. Subarus are reasonably thirsty compared to a more recent car. So, doing high mileage might be a good reason to replace at any time.

  • 1
    When you talk about garaging older cars, would you consider an '08 Altima Coupe to be in that category or do you mean older cars as in 'we make em different than we used to' old? I ask because my car is getting old with 140k miles and I am trying to decide if I want to put the effort and money into keeping it running!
    – Odin1806
    Feb 16, 2020 at 16:09
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    @Odin1806 My other half has a brand spanking new suzuki, and even that likes to be garaged. My car is 30 years older than yours. I just garage it all night.
    – Criggie
    Feb 16, 2020 at 18:49

I drive a 1986 Toyota Celica Supra. It's a beautiful machine and a joy to drive, and even though it's lower in miles than yours, I've learned a few things about keeping older cars running.

You're right in that there is no specific reason not to keep an old car on the road. Even factors such as improved fuel consumption of newer cars can be offset by the energy required to build the new car in the first place and the cost of trading the car in.

It's often said that a petrol engine will need a rebuild somewhere between 150-250,000 miles. This is generally because of the piston rings, which seal the combustion chamber as the piston moves in the cylinder. They're made of very hard metal, but they do eventually wear down by scraping against the metal walls. Most cars have redundant piston rings, usually 2, perhaps 3. It's argued that having your oil analysed by specialist companies can give you a clearer picture of the engine's innards - like a blood test for cars. Failing piston rings will show as either metal shavings in the sample, or larger than expected quantities of carbon products collecting in the oil from combustion 'blowing by' the rings. An easier way to detect this is to note the consistency of the oil as you change it according to schedule. If it becomes blacker and thicker on subsequent oil changes, you're most likely suffering piston ring wear. For the most part, changing piston rings involves removing the engine - this isn't as drastic as it sounds, and a well equipped garage can probably manage it in a day or two.

It's also important to note that short journeys can greatly accelerate engine wear, as the parts are designed to align properly only when the engine is at operating temperature, and until this is reached the parts may be out of alignment.

Other components wear over time, especially oil seals. A common failure is valve stem seals, which begin to leak oil either directly into the combustion chamber (intake side) or into the exhaust stream. This can produce impressive amounts of smoke from the exhaust. It also produces a characteristic puff of blue smoke from a cold start. These also require specialist tools to change (disarming springs etc.).

The good thing about major overhauls like this, however, is that they tend to last the same length of time again. If you have no foreseeable intention to change cars, this can be a good use of money versus buying another. Once these tasks are done, they won't need repeating for many years.

Gearbox failures are pretty rare, but gearboxes do wear through use. If it's a stick-shift (manual), the gears have brass rings known as synchros, which are used to bring the gears up to speed as you shift. Brass is a soft metal, deliberately used because it slightly deforms as the gears are swapped to give a smooth shift, but over time the rings wear down. This is where you get crunching between gears as the destination gear hasn't spun up to the correct speed. It can also make shifts very jerky, which in turn puts more stress on the cogs and can lead to mechanical failure of the gears. Changing the gearbox oil in line with the manufacturer's suggestions helps a lot - gearbox oil contains many additives to slow wear of these rings, but the tight tolerances of the gears causes 'shearing' where the oil is compressed between the teeth of the cogs, which breaks down some of the additives. Gearbox oil is more resistant than engine oil, but not immune. Some gearbox designs, Subaru included, incorporate filters that should be changed together with the fluid.

Automatic transmission fluid is slightly different as it's used as a hydraulic fluid, and as such is usually under pressure, since it's ultimately what causes the gears to shift. Mostly due to this, it tends to have a shorter life than manual transmission fluid. Automatic transmissions, however, don't suffer from clutch wear due to the fluid coupling. Almost all working surfaces in an auto-box are liberally coated with oil when in use, and if the oil level drops, the gearbox will quickly stop working properly before any major damage can be done. Old fluid can cause hydraulic pathways to clog up, causing jerky or missed shifts, but a professional drain, flush and replacement can bring it back to previous condition.

Gearboxes can be rebuilt, so the wear is not fatal, but it's an expensive job. Other components that incorporate gears, such as the rear differential, are vulnerable to the same failures. However, as you've reached 200,000 miles already without problems, it illustrates how tough these components are.

The mechanical aspects are, therefore, reasonably predictable. Good maintenance can see a car reach 500,000+ miles on the odometer. Other factors can cause problems, of course. Rust, as noted, is a major problem in older cars. My Supra is currently in a bodyshop having its sills rebuilt - despite little visible rust on the outer edge, the inner pieces of metal have disintegrated. Japanese cars have a well-earned reputation for rust problems - I also own a 2003 Subaru Outback, and discovered rust in the rear driver's wheel arch (fuel filler side). Apparently this is a common problem across all Subarus and is a spot to keep an eye on - I was able to poke a quarter-sized hole through the metal with just my thumb!

Rust and corrosion can also cause electrical issues, either through causing cables to chafe or terminals to corrode over. Car electrical problems are a dark art and very difficult to diagnose as an amateur mechanic - spoken from experience here!! Japanese cars restore their reputation here by having extremely reliable electricals and electronics - my Supra's electronics still work 100% after 31 years. However, if they do ever go wrong with a non-obvious problem, you'll generally need to enlist an automotive electrician. Especially older cars where individual cables drive each device - it amounts to miles of tightly bundled cables running the whole length of the car and can fail in odd places.

Mostly, it comes down to economics, but mechanically, there are few reasons why you can't keep a car running as long as you like.


Lubrication is the key. Even well maintained cars will gradually form sludge, varnish, and other deposits on valve stems, piston rings, valve train, fuel injectors, fuel pumps, EGR valves, O2 sensors, catalytic converters and cooling system. These deposits affect these parts adversely by starving them of lubricant or lose sensitivity -- causing the engine to burn lean/rich, lose compression and run hotter -- accelerating wear of all critical parts. The deposits can even be too small to see with the naked eye. I have been dealing with this phenomenon for years on my 23 year old car with 75k miles.

The key is to change the fluids much more frequently on an old car, using a flush for each system. Change the transmission fluid three times in a row, allowing 500 miles between changes (you can save money by pumping the fluid yourself through the dipstick). Do the same for the crankcase oil, substituting 20% with Marvel Mystery Oil. Coolant may look clean, but adding flush for a few days will dirty it by removing scale buildup. The power steering system will always have sludge looming in the rack, so suck the fluid out of the reservoir with a turkey baster at least five times over the course of days. Add Marvel Mystery Oil to the gas tank at a treat rate of 2 oz. per gallon and drive aggressively; at the next fill-up add two cans of Berryman's B12 Chemtool and floor it on the highway, 50-80 MPH, at least six times in a row.

Once the engine is really clean, condition it with Xado in the crankcase. After 1,200 miles, change the oil and filter.

I have revived several old cars in this manner. I've even stopped them from burning oil in two cases.

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