1991 · 33 years old at test · Petrol mostly

1991 Porsche 911 MOT pass rate and common faults

301 MOT tests in 2024. 88.0% passed first time, compared with 71.1% for all cars the same age.

124Well above average
Passed first time88.0%
Failed or needed repairs12.0%
Typical mileage at test90,000

Most common reasons for failing

Share of all 301 tests where this item caused a failure.

  1. Headlamp aim: too low1.7%
  2. Headlamp aim: too high1.7%
  3. Rear fog lamp: not working1.3%
  4. Horn: not working1.3%
  5. Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt1.0%
  6. Washers: provides insufficient washer liquid1.0%
  7. Linkage ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt0.7%
  8. Washers: not working0.7%
  9. Engine oil leaks: leaking excessively from engine0.7%
  10. Registration plates: does not conform to the specified requirements0.7%

Problem areas

Failure items found per 100 tests, by part of the car.

  1. Lights & electrics12.6%
  2. Visibility (wipers, screen, mirrors)3.0%
  3. Emissions & leaks2.0%
  4. Body & chassis1.7%
  5. Suspension1.7%
  6. Number plates & VIN0.7%
  7. Tyres0.7%
  8. Steering0.3%

Most common advisories

Not failures yet, but things the tester warned about.

  1. Engine oil leaks: leaking excessively from engine11.3%
  2. Tread depth below requirements of 1.6mm5.6%
  3. Tyres - condition: has a tear, caused by separation or partial failure of its structure2.7%
  4. Brake discs: in such a condition that it is seriously weakened2.0%
  5. Flexible brake hoses: ferrule excessively corroded1.7%

What this means if you are buying one

This model year does better than most cars its age, so it is a reasonable used buy on MOT record alone. Before buying, check the area that fails most: headlamp aim: too low. Then look up the car's own MOT history on GOV.UK with its number plate, and look for repeat advisories.

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Questions

What is the MOT pass rate for a 1991 Porsche 911?

In 2024, 88.0% of 1991 Porsche 911 cars passed their MOT first time, across 301 tests. The average for all 33-year-old cars was 71.1%.

What are the most common MOT failures on a 1991 Porsche 911?

The most common failure reasons were headlamp aim: too low; headlamp aim: too high; rear fog lamp: not working. The biggest problem area was lights & electrics.

Is the 1991 Porsche 911 reliable at MOT time?

Its MOT Rank score is 124, which is well above average for a car of its age (100 means exactly average).