BMW M5 owners have reported a total of 139 problems for their cars built in the 18 model years listed in the chart below. The chart shows the number of problems reported across all service years for each given model year of the BMW M5. The 2006 BMW M5 cars have the most problems reported (49 problems).
The following chart shows the 18 most common problems for BMW M5 cars. The number one most common problem is related to the vehicle's air bags (43 problems). The second most common problem is related to the vehicle's engine and engine cooling (24 problems).
It would not be fair to compare the BMW M5 of an older model year to newer model years since older vehicles have been in service longer and thus are expected to have more problems. In order to compare the reliability across M5 model years, we use the PPMY index which is defined as the problems reported per thousand vehicles per Year. A smaller PPMY index indicates greater reliability of the given model year cars.
PPMY = P / S / Y * 1000,
where P = total problems reported during the life of a BMW M5 model year; S = total units sold of the model year; Y = years since the debut of the model year (the age of the vehicle).
The results are shown in Table 3.