We have updated the reliability stats for the Boxster and Cayman to include owner experiences through March 31, 2011.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008: 41, better than average

2007: 65, about average

2006: 54, better than average

2005: 73, about average

2004: 62, better than average, small sample size

2003: 65, better than average

2002: 112, about average

2001: 83, better than average

2000: 84, better than average

1999: 97, better than average, small sample size

Important note: these cars are only driven an average of 5,500 miles a year, about half as much as the average car. No adjustment has been made for this.

Six IMS failures were reported for the 2010 calendar year, most of them for 2004-2005 model year cars (with the 2005 being a 987 rather than a 986).

No IMS failures have been reported for cars 2006 and newer. None have been reported for any year since the beginning of 2011, with over 220 owners of 1999-2005 cars participating.

Rear main seal and air/oil separator repairs are far more common.

We'll have further updates in August and November. With more participants we could provide more precise information and cover all model years.

To see how competitors compare, and to sign up to help improve this information:

Porsche Boxster reliability ratings and comparisons

This is good info. Like other I've wondered about IMS failure rates.

We have updated reliability stats for the Boxster and Cayman that include owner experiences through September 30, 2011.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008: 28, better than average

2007: 75, about average, might be high because final year of standard warranty

2006: 39, better than average

2005: 72, about average

2004: 44, better than average, small sample size

2003: 53, better than average

2002: 135, about average

2001: 97, better than average

2000: 120, about average

1999: 71, better than average, small sample size

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

For the years where we have enough data for these:

2008: 67, < 1

2006: 65, < 1

2001: 51, 11

Porsche Boxster Lemon-odds and Nada-odds

Important note: these cars are only driven an average of 5,500 miles a year, about half as much as the average car. No adjustment has been made for this.

Six IMS failures were reported for the 2010 calendar year, most of them for 2004-2005 model year cars (with the 2005 being a 987 rather than a 986).

No IMS failures have been reported for cars 2006 and newer.

No IMS failures have been reported for any model year since the beginning of 2011, with over 200 owners of 1999-2005 cars participating.

Rear main seal and air/oil separator repairs are far more common.

Thank you, once again, to everyone who has been helping. We'll have further updates in February and May. With more participants we could provide more precise information and cover all model years.

To see how competitors compare, and to sign up to help improve this information:

Porsche Boxster reliability ratings and comparisons

We have updated reliability stats for the Boxster and Cayman that include owner experiences through December 31, 2011.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008: 31, better than average

2007: 72, about average, might be high because final year of standard warranty

2006: 49, better than average

2005: 56, better than average

2004: 16, better than average, small sample size

2003: 42, better than average

2002: 97, better than average

2001: 95, better than average

2000: 100, about average

1999: 60, better than average

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

For the years where we have enough data for these:

2008: 72, < 1

2006: 71, 4

2005: 49, 4

2001: 42, 4

Important note: these cars are only driven an average of 5,500 miles a year, about half as much as the average car. No adjustment has been made for this.

Six IMS failures were reported for the 2010 calendar year, most of them for 2004-2005 model year cars (with the 2005 being a 987 rather than a 986).

No IMS failures have been reported for cars 2006 and newer.

No IMS failures have been reported for any model year since the beginning of 2011, with over 200 owners of 1999-2005 cars participating.

Rear main seal and air/oil separator repairs remain far more common.

Thank you, once again, to everyone who has been helping. We'll have further updates in May and August. With more participants we could provide more precise information and cover all model years.

To see how competitors compare, and to sign up to help improve this information:

Porsche Boxster reliability ratings and comparisons

Porsche Boxster repair odds

We have updated reliability stats for the Boxster and Cayman that include owner experiences through June 30, 2012.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008: 42, about average, stricter recalibrated scale

2007: 34, better than average

2006: 45, better than average

2005: 33, better than average

2004: 29, better than average, small sample size

2003: 38, better than average

2002: 65, better than average

2001: 78, better than average

2000: 70, better than average

1999: 110, about average

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

For the years where we have enough data for these:

2008: 72, 6

2006: 65, 4

2005: 73, 3

2002: 59, 8

2001: 58, 3

Important note: these cars are only driven an average of 5,500 miles a year, about half as much as the average car. No adjustment has been made for this.

Six IMS failures were reported for the 2010 calendar year, most of them for 2004-2005 model year cars (with the 2005 being a 987 rather than a 986).

No IMS failures have been reported for cars 2006 and newer.

No IMS failures have been reported for any model year since the beginning of 2011, with over 200 owners of 1999-2005 cars participating.

Rear main seal and air/oil separator repairs remain far more common.

We'll have further updates in November and February. With more owners involved we could provide more precise information and cover all model years.

To see how competitors compare, and to sign up to help improve this information:

Porsche Boxster reliability ratings and comparisons

We have updated reliability stats for the Boxster and Cayman that include owner experiences through September 30, 2012.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008: 42, about average, stricter recalibrated scale

2007: 29, better than average

2006: 38, better than average

2005: 34, better than average

2004: 50, better than average, small sample size

2003: 46, better than average

2002: 67, better than average

2001: 80, better than average

2000: 44, better than average

1999: 117, worse than average

We have two additional statistics, "Nada-odds" and "Lemon-odds," to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop.

For the years where we have enough data for these:

2008: 68, < 1

2006: 74, 4

2005: 78, 3

2001: 44, < 1

Important note: these cars are only driven an average of 5,500 miles a year, about half as much as the average car. No adjustment has been made for this.

Six IMS failures were reported for the 2010 calendar year, most of them for 2004-2005 model year cars (with the 2005 being a 987 rather than a 986).

No IMS failures have been reported for cars 2006 and newer.

No IMS failures have been reported for any model year since the beginning of 2011, with over 200 owners of 1999-2005 cars participating.

Update: one case of a leaking but not failed IMS reported after September 30th.

Rear main seal and air/oil separator repairs remain far more common.

We'll have further updates in February and May. We'd love to provide more precise stats and cover more model years--just a matter of getting more owners involved.

To see how competitors compare, and to sign up to help:

Porsche Boxster reliability ratings and comparisons

We've updated our reliability stats for the Boxster to include owner experiences through March 31, 2013.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008 Boxster: 38, low
2007 Boxster: 43, low
2006 Boxster: 21, low
2005 Boxster: 21, low
2004 Boxster: 52, low, small sample size
2003 Boxster: 48, low
2002 Boxster: 64, low
2001 Boxster: 46, low
2000 Boxster: 23, low
1999 Boxster: 105, moderate

We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:

2008 Boxster: 69, < 1
2006 Boxster: 83, < 1
2005 Boxster: 85, < 1
2001 Boxster: 60, < 1

Still no reports of IMS failures since the beginning of 2011.

We'll have further updates in August and in November. The more owners participate, the more comprehensive and precise these will be.

For the details, including the descriptions of reported repairs, and to sign up to help improve this information:

Porsche Boxster reliability ratings and comparisons

We've updated our reliability stats for the Boxster to include owner experiences through June 30, 2013. (Another source is about 14 months behind.)

Repair frequencies, in terms of repair trips per 100 cars per year:

2008 Boxster: 32, low
2007 Boxster: 49, moderate
2006 Boxster: 22, low
2005 Boxster: 25, low
2004 Boxster: 40, low, small sample size
2003 Boxster: 43, low
2002 Boxster: 63, low
2001 Boxster: 49, low
2000 Boxster: 37, low
1999 Boxster: 71, low

We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:

2008 Boxster: 72, < 1
2007 Boxster: 65, < 1
2006 Boxster: 86, < 1
2005 Boxster: 81, < 1
2001 Boxster: 62, < 1

We'll have further updates in November and February.

To view competitors' scores and descriptions of reported repairs, and to sign up to help:

Porsche Boxster reliability ratings and comparisons

signed up!!!!!!!

How should we adjust for this caveat:

"Important note: these cars are only driven an average of 5,500 miles a year, about half as much as the average car. No adjustment has been made for this."

For example, would we double the numbers here, to make them more comparable to cars that are driven 11k per year?

As an example, BMW 330is from early in the 2000s have 'yellow' reliability with visits per 100 of around 120. The Boxster has 'green' reliability and visits per 100 of around 50. Having had several 330i's, they are far less scary to own.

We've updated our reliability stats for the Boxster to include owner experiences through September 30, 2013.

Repair frequencies, in terms of repair trips per 100 cars per year:

2008 Boxster: 29, low
2007 Boxster: 46, low
2006 Boxster: 26, low
2005 Boxster: 22, low
2004 Boxster: 42, low, small sample size
2003 Boxster: 60, low
2002 Boxster: 62, low
2001 Boxster: 56, low
2000 Boxster: 30, low
1999 Boxster: 42, low

We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:

2008 Boxster: 71, < 1
2007 Boxster: 75, < 1
2006 Boxster: 77, < 1
2005 Boxster: 75, < 1
2001 Boxster: 60, < 1

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:

Porsche Boxster reliability ratings and comparisons

I'm not sure how to adjust for it. Some problems occur due to due, not miles, so it's not a simply linear function. Driving conditions, number of cold starts, etc. also make a difference. Many Porsches are garaged during the winter, and winter miles are likely much harder on cars.

In general I'm thinking we might need a different way to measure reliability with older cars, as people start letting the small stuff slide. We're going to start posting a second set of stats that include only problems with the powertrain and chassis, and these might be better for older cars.

We've updated our reliability stats for the Boxster to include owner experiences through December 31, 2013.

Repair frequencies, in terms of repair trips per 100 cars per year:

2013 Boxster: 0, low, small sample size
2008 Boxster: 33, low
2007 Boxster: 47, low
2006 Boxster: 39, low
2005 Boxster: 40, low
2004 Boxster: 47, low, small sample size
2003 Boxster: 52, low
2002 Boxster: 85, moderate, small sample size
2001 Boxster: 57, low
2000 Boxster: 39, low
1999 Boxster: 24, low, small sample size

We have had one report in the past two years of an IMS bearing failure, to a car that had the bearing upgraded when its clutch was changed.

We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:

2008 Boxster: 74, < 1
2006 Boxster: 67, < 1
2001 Boxster: 65, 3

We'll have further updates in May and in August. The more owners participate, the more comprehensive and precise these will be.

To see the repairs behind these stats, and to sign up to help improve this information:

Porsche Boxster reliability ratings and comparisons

Thanks, Michael! I use your site regularly for the many cars i buy and cars I help others buy. I use the above, plus look thru the reported repairs plus go to the public library and read the All Data TSBs to get a feel for what someone may expect.

How do you think the quoted 9% failure rate for single row cars compares to your sample statistics? And maybe you can explain to me what 9% means - I assume from the time they were built till whenever the lawsuit started that 9% of all the cars produced had had the failure in that time regardless of miles or varying age?

By "single row cars" do you mean the Boxster and Cayman?

The thing with these failure rates is that they probably include the entire history of the cars. Many IMS failures occurred years ago. What current owners want to know is how often they're still happening. In our data they're hardly ever still happening.

sometime in 2000, they switched from two rows of ball bearings to one row. The statistics used for the law suit says the dual row had fewer failures than the single row. Later (I think 2006) a bigger single row was used that appears to have fewer problems. Mine is a 2002 S.

Thanks for the info, I hadn't realized this. This makes most of the 986s in the survey single-row cars--unless the bearings were upgraded / replaced with something else. With over 200 cars involved, we've had one reported failure in the past two years--to a car with an upgraded bearing. My sense is that they're not likely to fail after a certain number of miles, and upgrading the bearing reset the clock.

Thanks for the info Michael . I just reenrolled after changing my email address. You do a great service to the car community.
Cheers, Guy

From what I've read it's not that simple. Any MY 2000 car "should" have a dual row IMSB. But there's no simple engine serial number cut off. Single row IMSBs started appearing apparently at random in 2000 and there were many dual row IMSBs still installed in MY 2001 cars. I specifically sought out a MY 2000 car since it wouldn't have the casting problems of the 2.5l cars yet it "should" have a dual row IMSB. My engine serial number is in the "safe" range....but that's not conclusive.

So this summer I plan to drop the tranny. pull the clutch and flywheel, and inspect the IMSB cover. Only then will I know for sure which IMSB I have. If it's a single row I'm putting an LN bearing in. If it's a dual row.....I may just put it back together with a new RMS and clutch and forget about it.