Which year BMW 523 is most reliable?
Based on 20,668 vehicles (1996–2011) and millions of DVLA MOT records.
Pass rate by year
Click any year to see full MOT history, common faults and comparisons for those cars. Verdicts are relative to this model's own average — a good Land Rover year is judged differently from a good Toyota year.
How each year holds up at higher mileage
Each line is a different model year. The mileage ranges are divided into 5 equal groups based on how this model is actually driven in the real world — so you're comparing like-for-like, not arbitrary round numbers.
Only years with enough data across at least 3 mileage ranges are shown. Newer years appear in blue; older years in amber.
How is this measured?
What "pass rate" means
The percentage of all MOT tests that resulted in a pass — counted across a car's whole life, not just its first test. Higher means fewer failures over time.
Mileage groups built from real data
We split this model's real-world mileage history into 5 equal groups — so each slice contains the same number of cars, not an arbitrary round number like "0–30,000 miles."
Does age still matter?
Yes. A low-mileage 20-year-old car has still had 20 years of weather, perishing rubber, and ageing electrics. Comparing at the same mileage narrows the gap between old and new — but doesn't erase it entirely.
Why this beats surveys
Our figures come from the DVLA's national MOT database — over 50 million real test results from accredited garages, with no opinions involved. Most reliability guides are based on owner surveys with a few hundred responses per model.