Cars do die sooner or later .Sure there are stats on average age .My question is what causes of death are more likely ? Are they most likely to be Written off due to needing repairs that exceed replacement cost ?How likely is Rust to be the cause of death ? Modern cars have better corrosion protection ,break down less and are more complicated to fix ,How does this change things? Do locations with tough MOT inspections have an impact?

  • I'm voting to close this question as too broad, cars have evolved enormously over time and the causes of cars being taken off the road are many. It's also hugely variable on location.
    – GdD
    Jul 5 '19 at 9:24
  • 1
    A huge factor is the lack of maintenance...
    – Solar Mike
    Jul 5 '19 at 11:29

This is a fearsomely broad question and probably not really in keeping with the spirit of this group in that it doesn't ask for details for a specific mechanical issue but I will attempt to answer.

The "cause of death" or reason that a car may be scrapped in the UK at least falls into a number of groups;

  • Damaged due to accident, fire or flooding. Depending on the insurance company, finance company, owner and vehicle inspector, a vehicle may be classified as salvage once one of these events has occurred. When being classified as salvage, a vehicle will be classified into a number of categories. Category A and B vehicles may not be returned to the road, they may not be purchased by anyone without a salvage licence and they must be dismantled.

Cat A vehicles must be crashed / shredded and may be melted down for recycling. Cat B vehicles may have components removed and sold but the structure of the vehicle itself is so compromised that it is illegal to return it to the road. The majority of salvage vehicles you will see at auctions will be lesser categories which may be purchased without a salvage licence and may be returned to the road if repaired.

The lower categories split off into two broad groups although their salvage category doesn't already reflect this. They will either be in the form of damaged vehicles that my be repaired or damaged vehicles that may be repaired BUT are judged to be uneconomical to repair. The uneconomical to repair assessment depends largely on the extent of the damage and the vehicles age. I once purchased a vehicle that was classified as uneconomical to repair because it was 15 years had a smashed headlight and front bumper. The manufacturers list price for the headlight and bumper plus estimated fitting time far exceeded the couple of hundred pounds that the vehicle was assessed to be worth.

So, having a salvage title doesn't mean the "death" of a vehicle unless it's a Cat A or Cat B vehicle.

  • Theft of motor vehicle. This is effectively where the vehicle disappears from the face of the earth. It may be stolen and broken up for parts by thieves in which case the insurers would pay out and the DVLA mark the vehicle as stolen. Occasionally a previously stolen vehicle appears again, sometimes many years later and often wearing the chassis tags and registration of another vehicle. A common ploy is for thieves to buy a damaged but still repairable vehicle or in the case of older vehicles, a poor condition vehicle then steal an identical vehicle and swap the identities. Be warned, in the UK at least, if you purchase a stolen vehicle, it isn't yours and you will lose the vehicle and whatever money you paid for it if this is discovered at a later date.

  • Electronic or Mechanical failure. Typically this will happen once a vehicle reaches it's teen years. Something catastrophic happens to it such as a timing belt snaps, a differential or gearbox fails or the ECU electronics fail. This leaves the vehicle in an unusable state with an owner being quoted repair bills of several hundred or even thousands of pounds. They may then take the decision that it is cheaper to scrap the vehicle and buy another than to spend money on a costly repair for a vehicle which has a relatively low value.

  • Severe MOT failure. Again, this typically happens in a vehicles twilight years when it's at that awkward age when it's too old to be considered modern and too new to be considered classic. A vehicle may have a sale value of a few hundred pounds. In this case, an MOT failure for something like an ABS unit combined with failed emissions tests, a couple of hundred pounds worth of welding and a pair of tyres is more than enough to put a "banger" into the scrap yard.

  • Failed restoration / spares vehicle. There is another class of end-of-life vehicles that are generally much older than the others. If a vehicle makes it to the age where it is considered a classic, if it suffers any of the above incidents an owner or buyer may still see potential in the vehicle. This can lead to a vehicle being purchased or kept as a restoration projects. Vehicles may be kept in this state for years or even decades. At some point an owner may decide that too much work is involved or they are offered another vehicle in a better condition. At this point a vehicle may be designated as "spares" and broken up to keep it's sibling on the road.

  • Motorsport. Some vehicles end up coming off the road for motorsport use. This may be something as simple as a vehicle ending up in a banger race or may be a vehicle stripped and recreated as a track-car. Typically motorsport is so hard on a vehicle that it will need constant repair and at some point it will be re-shelled at which point the road car that originally became the race car falls into the same "spares vehicle" trap as a failed restoration. NOTE. This does not happen to all motorsport vehicles.


There are statistics on mandatory inspection failures.

I think rust may be the deciding factor when it's considered whether to repair or replace, but as the cause of mandatory inspection failure, it's actually not on the top of the list.

Suspension and braking faults are one of the most common cases of mandatory inspection failures. They, unlike rust, can however be repaired reasonably easily.

Actually, the most common fault in inspections is a burnt light bulb. This, however, typically does not lead to a failure but rather the owner is asked to replace it without requiring a mandatory second inspection.

  • In the UK any cause of failure (even a blown bulb) results in a recorded test failure and a complete re-inspection if the car is removed from the test location before the problem is fixed. Of course most people would rather pay the test center to replace the bulb (which is often done "free" apart from the cost of the bulb itself) rather than exercise their right to take the car away and do the job themselves.
    – alephzero
    Jul 5 '19 at 10:56
  • @alephzero Not quite - failure in certain areas (including things like bulbs) can be removed from the test centre for repair, with just the failure items needing to be re-tested, unless that's changed recently.
    – Nick C
    Jul 5 '19 at 12:05
  • Yep - last year I had an old Honda Jazz fail on structural bodywork. Took it to a welder, fixed it, returned to the MOT centre and they just retested that structure.
    – Rory Alsop
    Jul 5 '19 at 14:00
  • UK MOT rules are such that a vehicle repaired within 10 working days may be subjected to a partial retest which is half the original fee (if the centre decides to charge) and inspects only the failure items plus reinspecting anything else that may have been affected during the repair. Jul 5 '19 at 14:23

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