E9X 3-Series reliability survey results

mkaresh · 02-26-2008, 11:19 AM

The latest TrueDelta Vehicle Reliability Survey results have been posted. These are for the year ending December 31, 2007.

For the 2006 BMW 3-Series sedan, we received an average of 6.7 months of data on 45 cars. The stat of 84 successful repair trips per 100 vehicles per year (0.8 per vehicle) is about average, perhaps a bit worse, for a 2006 model. Notably, after increasing for a number of periods, the repair rate appears to have leveled off.

For the 2007 BMW 3-Series, we received an average of 6.0 months of data on 61 cars. The stat of 49 successful repair trips per 100 vehicles per year (0.5 per vehicle) is about average, maybe a little better than average, for a 2007 model. Like the result for the 2006, this one is very close to the one released three months ago.

I've read many anecdotal accounts of high problem rates with the 335i's engine. This is not supported by these results. Four engine issues were reported for the 335i, of which there were 37 in the sample. These included a head gasket (for a minor oil leak), a fuel pump, a VANOS solenoid, and an adjustment to the camshaft timing. None were major engine failures.

Everyone who has been helping out with this research, thank you. Those who aren't yet helping out, please consider doing so. With larger sample sizes we'd be able to provide additional detail. More participants are especially needed for the 2008, which should be in the next update, in May.

Full set of results:

TrueDelta Vehicle Reliability Survey results

John 070 · 02-26-2008, 11:42 AM

61 cars for 2k7, and 45 cars for 2k6, is neither statistically reliable nor valid imho. No conclusions can be drawn from samples of those sizes imho.

Potty_Pants · 02-26-2008, 12:28 PM

mike man,

you got too much time on your hands... every forum i goto your there !

*applaud*

ppp

BMW335icDDS · 02-26-2008, 01:00 PM

The data sizes are very very small. I'm not sure I can believe the results either.

roadkillrob · 02-26-2008, 01:38 PM

So BMW sold 508,000 3-series in 2006 and 555,000 in 2007, so this survey accounts for .009% of the total, less than 1 in 1000 cars - statistically the margin of error on that many units is much higher than the number of cars in the survey.

02-26-2008, 11:19 AM	#1
mkaresh Second Lieutenant 18 Rep 267 Posts Drives: 2000 Lexus GS 400 Join Date: Jan 2007 Location: Michigan iTrader: (0)	E9X 3-Series reliability survey results The latest TrueDelta Vehicle Reliability Survey results have been posted. These are for the year ending December 31, 2007. For the 2006 BMW 3-Series sedan, we received an average of 6.7 months of data on 45 cars. The stat of 84 successful repair trips per 100 vehicles per year (0.8 per vehicle) is about average, perhaps a bit worse, for a 2006 model. Notably, after increasing for a number of periods, the repair rate appears to have leveled off. For the 2007 BMW 3-Series, we received an average of 6.0 months of data on 61 cars. The stat of 49 successful repair trips per 100 vehicles per year (0.5 per vehicle) is about average, maybe a little better than average, for a 2007 model. Like the result for the 2006, this one is very close to the one released three months ago. I've read many anecdotal accounts of high problem rates with the 335i's engine. This is not supported by these results. Four engine issues were reported for the 335i, of which there were 37 in the sample. These included a head gasket (for a minor oil leak), a fuel pump, a VANOS solenoid, and an adjustment to the camshaft timing. None were major engine failures. Everyone who has been helping out with this research, thank you. Those who aren't yet helping out, please consider doing so. With larger sample sizes we'd be able to provide additional detail. More participants are especially needed for the 2008, which should be in the next update, in May. Full set of results: TrueDelta Vehicle Reliability Survey results
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02-26-2008, 11:42 AM	#2
John 070 Lieutenant General 1706 Rep 14,829 Posts Drives: 335i cpe Join Date: Oct 2006 Location: ZSP/ZPP/ZCW iTrader: (0)	61 cars for 2k7, and 45 cars for 2k6, is neither statistically reliable nor valid imho. No conclusions can be drawn from samples of those sizes imho.
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02-26-2008, 12:28 PM	#3
Potty_Pants Colonel 67 Rep 2,189 Posts Drives: 2012 Genesis Sedan Rspec Join Date: Apr 2007 Location: Southern NJ iTrader: (0)	mike man, you got too much time on your hands... every forum i goto your there ! applaud ppp __________________ Olds Starfire > Chevy Malibu > Isuzu I-mark RS & Honda Magna 500 > Grand Am GT & YSR50 > Nissan Maxima & Ninja 750 > X-Wife > Hyundai Excel > Honda Prelude > Honda Accord > Honda Prelude & Ninja 250> Infiniti G35 > E90 335i > Hyundai Genesis Rspec, Hyunadai Sonata > Kia Sorento > Honda CRV-EX
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02-26-2008, 01:00 PM	#4
BMW335icDDS Doctor 32 Rep 634 Posts Drives: RRSport, 335vert, 997 S, Sc430 Join Date: Feb 2007 Location: Los Angeles and New York iTrader: (0) Garage List 2007 Porsche 997S [0.00] 2007 Porsche 997S [0.00] 2007 BMW 335 E93 [9.00]	The data sizes are very very small. I'm not sure I can believe the results either. __________________ 2002 Lexus Sc430 2007 BMW 335i Convertible Space Gray on Coral Red 2007 Porsche Carrera S 2011 Range Rover Sport HSE Lux UCLA D.D.S. Columbia University Dental Specialist
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02-26-2008, 01:38 PM	#5
roadkillrob Major General 875 Rep 5,457 Posts Drives: 08 335i,22 X3M, 2012 C63 Black Join Date: Jul 2007 Location: Boston iTrader: (15)	So BMW sold 508,000 3-series in 2006 and 555,000 in 2007, so this survey accounts for .009% of the total, less than 1 in 1000 cars - statistically the margin of error on that many units is much higher than the number of cars in the survey.
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