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Porsche 911 vs Porsche 997-1: reliability comparison

MOT pass rates, common faults and mileage compared from real UK MOT data.

Porsche 911
85%
MOT pass rate · 74,656 vehicles
Porsche 997-1
86%
MOT pass rate · 1 vehicles
Verdict: On MOT pass rate the Porsche 911 (85%) and Porsche 997-1 (86%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Head to head

Measure Porsche 911 Porsche 997-1
MOT pass rate 85% 86% ✓
MOT failure rate 15% 14% ✓
Faults & advisories per test 1.1 ✓ 2.0
Dangerous-fault share 1% 0% ✓
Average mileage 70,982 mi 97,249 mi
Sample size (vehicles) 74,656 1

Most common faults

Porsche 911

  1. Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
  2. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  3. Under-trays fitted obscuring some underside components
  4. Nearside Front Tyre worn close to the legal limit (4.1.E.1)
  5. Offside Front Tyre worn close to the legal limit (4.1.E.1)
  6. Oil leak, but not excessive (8.4.1 (a) (i))

Porsche 997-1

  1. Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
  2. Offside Rear Tyre worn close to the legal limit (4.1.E.1)
  3. Front Brake pad(s) wearing thin (3.5.1g)
  4. Under-trays fitted obscuring some underside components
  5. Nearside Front brake disc slightly pitted (3.5.1h)
  6. Offside Front brake disc slightly pitted (3.5.1h)

Reliability FAQ

On MOT pass rate the Porsche 911 (85%) and Porsche 997-1 (86%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.

Full Porsche 911 report Full Porsche 997-1 report Most reliable cars

Pass rates are computed over completed (pass/fail) MOT tests. Reliability also depends on age, mileage and upkeep — see each model's page for the full picture.