mkaresh

TrueDelta reports absolute repair rates that make the differences between cars much clearer. Results are updated four times a year, to track cars closely as they age.

Among Mercedes, we currently provide results for the C, E, and GL. No year of the S-Class is included in the survey yet. For a model year to be included, at least 25 owners have to sign up to participate.

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 S-Class, free of charge.

For the details, and to sign up to help out:

Car reliability research

mkaresh

60 S-Class owners signed up so far. A good start, but more are needed for us to provide reliability stats on these cars.

softgenious

What do they look like so far?

mkaresh

I don't want to waste anyone's time, so a model year isn't included in the main reliability survey until at least 25 owners have signed up. We're not there yet. At this point just seeing if we can get enough owners to agree to participate.

There are some other surveys on the site, such as the one for real-world fuel economy, that have no minimum. Those are entirely optional.

mkaresh

Now 70 owners. Closer to including these cars in the survey.

mkaresh

Now 79. Updated results for the C, E, and GL in August.

mkaresh

Now 88. The 2007 is now halfway to the minimum.

Help get your year included in the survey:

Car reliability research

mkaresh

Now 94, and the 2007 is just ten cars short of the minimum. Updated results for the C, E, and GL recently posted.

mkaresh

Now 103, and the 2007 is just six cars short of the minimum.

To help get your year included--I'd like to have some results to share here:

Car reliability research

mkaresh

Now 119, and the 2007 has been added to the survey. Thanks, guys.

Additional participants remain needed, for all model years.

CL55_Serge

here is a data point - i was told that Mercedes put something like 60k miles on 221 model before claiming victory on the vehicle, i guess in late '05 or early '06 when the 221 became available. shop foreman here in San Jose feels like the 221 is more solid than 220 and possibly an example of most reliable S to date (in the recent years - I guess since W126).

would you guys agree? has anyone heard of the quality control test drive of 60k miles or so on multiple 221 cars before making the model generally available?

T0ked

I have to say I am very pleased with the reliability of the W221. My father's W220 was plagued for the first year (spent almost 3 months in the shop first year alone) and was a bit hesitant with the W221 but took the plunge anyway. I have not had the car in for anything since purchase.

mkaresh

Now 121 signed up. A good start, but more remain needed to provide results for all model years. Results recently upddated for the C, E, and GL.

Car reliability research

mkaresh

Now 129. Better, but more remain needed to provide reliability stats for these cars.

Not yet signed up? Details here:

Car reliability research

mkaresh

I'd like to have an initial result for the 2007 in May, but it's going to be tight. Currently we're a couple of participants short of the minimum.

mkaresh

Now 148 signed up, plus another 12 for the CL. I should know in the next day or two whether we'll have that result in May.

Not yet signed up? Help make this happen:

Car reliability research

mkaresh

Not enough data for a result in May, but on track for one in August.

The more owners participate, the better the information we can provide.

mkaresh

162 now signed up, and the 2008 is only ten owners short of the minimum needed to add it to the survey.

mkaresh

Still a little short for a result next month of the 2007. Hopefully we'll get the needed two or three responses.

Additional participants would certainly be helpful, and appreciated.

mkaresh

We have an initial result for the W221 S-Class based on owner experiences through June 30, 2010. With a reported repair frequency of 154 repair trips per 100 cars per year, the 2007 is worse than average.

This is based on a very small sample size.

We'll have further updated in November and February. With more participants, we could provide more precise results and cover more model years.

For more detailed results, and to sign up to help:

Hyundai Elantra Touring reliability comparisons

mkaresh

Sorry, didn't remember to modify the link.

The correct link would have been:

Mercedes-Benz S-Class reliability comparisons

mkaresh

Next week we'll start previewing the next set of results to participants. The preview results will be updated as responses come in.

As always, the more owners participate, the better the information we can provide to everyone.

Car reliability research

mkaresh

Starting this month we have a new question to measure, as objectively as possible, the severity of a problem. Many people have been asking for reliability stats that weight problems by how severe they are, and once we have enough responses with the revised survey we'll start providing this.

Also, updated reliability stats this month.

As always, the more owners participate, the better the information we can provide to everyone.

Car reliability research

mkaresh

We updated results for the W221 S-Class based on owner experiences through September 30, 2010. With a reported repair frequency of 129 repair trips per 100 cars per year, the 2007 is worse than average.

This is based on a small sample size, so the result is not precise.

We'll have further updated in February and May. With more participants, we could provide more precise results and cover more model years.

For more detailed results, and to sign up to help:

Mercedes-Benz S-Class reliability ratings and comparisons

mkaresh

We updated results for the W221 S-Class based on owner experiences through December 31, 2010. With a reported repair frequency of 105 repair trips per 100 cars per year, the 2007 is worse than average.

This is based on a small sample size, so the result is not precise. The reported repair frequency has been decreasing as we receive data on more cars. It's probably also lower for more recent model years.

We'll have further updated in May and August. With more participants, we could provide more precise results and cover more model years.

For more detailed results, and to sign up to help:

Mercedes-Benz S-Class reliability ratings and comparisons