W166 M-Class reliability - better info
We've been providing reliability stats for a number of Mercedes-Benz models, and would like to do the same for the latest M-Class. Just a matter of getting enough owners involved--with the 2012 we're about half way there.
Participants simply report repairs the month after they occur on a one-page survey. When there are no repairs, they simply report an approximate odometer reading four times a year, at the end of each quarter.
To encourage participation, participants receive full access to all results, not just those for the M-Class, for free. I'll share results for the W166 in this thread after each update.
For the details, and to sign up to help:
Car reliability research
The reported repair frequency so far, 44 repair trips per 100 cars per year, is moderate.
This is based on a fairly small amount of data. We'll have updated stats in May and August. The more owners participate, the more precise these will be.
To see how competitors compare, and to sign up to help:
Mercedes-Benz M-Class reliability ratings and comparisons
This statement does allow for the fact that the W166 has only been on sale for one year here.
Based on our survey data, the latest generation of Mercedes are considerably more reliable than the cars they replaced--but do get less reliable (if still not unreliable) after the first couple of years. They start out really good, then decline to around the average for all cars.
Repair frequencies, in terms of repair trips per 100 cars per year:
2012 M-Class: 79, high, very small sample size
We'll have further updates in August and in November.
For the details, including the descriptions of reported repairs, and to sign up to help improve this information (I'd love to get ride of the bit about the "small sample size"):
Mercedes-Benz M-Class reliability ratings and comparisons
Trending Topics
Repair frequencies, in terms of repair trips per 100 cars per year:
2013 M-Class: 17, low, small sample size
2012 M-Class: 61, high, very small sample size
We'll have further updates in November and February.
To view competitors' scores and descriptions of reported repairs, and to sign up to help:
Mercedes-Benz M-Class reliability ratings and comparisons
The Best of Mercedes & AMG
Repair frequencies, in terms of repair trips per 100 cars per year:
2013 M-Class: 35, moderate, small sample size
2012 M-Class: 76, high, very small sample size
We'll have further updates in February and in May. The more owners participate, the more comprehensive and precise these will be.
To see how competitors compare, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons
I think that this would validate the notion that the MB W166 is simply "ok" at best in terms of initial quality. Certainly I've had a below average experience and others seem to have had a better experience. Even people who say they love their cars have had little annoying issues which require trips to the spa...
Repair frequencies, in terms of repair trips per 100 cars per year:
2013 M-Class: 23, low, small sample size
2012 M-Class: 67, high, very small sample size
We'll have further updates in May and in August. The more owners participate, the more comprehensive and precise these will be. (I'd love to get rid of those "small sample size" notes.)
To see the repairs behind these stats, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons
Repair frequencies, in terms of repair trips per 100 cars per year:
2013 M-Class: 24, low, small sample size
2012 M-Class: 47, moderate, small sample size
Thank you, once again, everyone who has been helping. Next update in August.
For a deeper dive, including the stats for other cars and repair descriptions, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons
Repair frequencies, in terms of repair trips per 100 cars per year:
2013 M-Class: 23, low, small sample size
2012 M-Class: 39, moderate, very small sample size
Next updates in November and in February. The more owners participate, the more comprehensive and precise these will be. (I've love to get rid of those sample size disclaimers.)
For repair descriptions, the stats of other cars, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons
Repair frequencies, in terms of repair trips per 100 cars per year:
2014 M-Class: 12, low, very small sample size
2013 M-Class: 16, low, small sample size
2012 M-Class: 63, high, small sample size
Additional participants always helpful (especially if you see "small sample size" next to the year, or no stat at all).
To view the repairs behind these numbers, check the stats for other cars, and sign up to help improve this information (next update in February):
Mercedes-Benz M-Class reliability ratings and comparisons
Repair frequencies, in terms of repair trips per 100 cars per year:
2014 M-Class: 31, moderate, very small sample size
2013 M-Class: 40, moderate, small sample size
2012 M-Class: 66, high, small sample size
To see how competitors compare, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons
This statement does allow for the fact that the W166 has only been on sale for one year here.

www.truedelta.com/join
Our reliability stats for the M-Class now include owner experiences through March 31, 2015. (Others are nearly a year behind.)
In terms of repair trips per 100 cars per year ("low" is best):
2014 M-Class: 36, moderate, small sample size
2013 M-Class: 52, moderate, small sample size
2012 M-Class: 67, high, small sample size
No stat for a model year? Then we very much need more participants for it. Same for those with small sample size notes--unfortunately, all of them. Next updates in August and November.
For repair descriptions, the stats for other cars, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability
2014 M-Class: 36, moderate, small sample size
2013 M-Class: 50, moderate, small sample size
2012 M-Class: 84, high, small sample size
For the descriptions of all reported repairs, results for other models, and to sign up to help get rid of those "small sample size" notes:
Mercedes-Benz M-Class reliability ratings and comparisons
2014 M-Class: 48, moderate, small sample size
2013 M-Class: 51, moderate, small sample size
2012 M-Class: 63, moderate, very small sample size
We'll have further updates in February and in May. Additional participants are needed to provide precise stats for all model years.
For the details, including repair descriptions, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons
2014 M-Class: 18, low, small sample size
2013 M-Class: 54, moderate
2012 M-Class: 55, moderate, small sample size
No stat, or a small sample size? Then we especially need more owners involved for that model year.
For the repairs behind these stats, reliability information on other models, and to sign up to help improve this information:
Mercedes-Benz M-Class reliability ratings and comparisons



