Because existing sources of auto reliability information left much to be desired, in late 2005 I started conducting my own reliability research at TrueDelta.com. TrueDelta reports absolute stats like "trips to the shop" that make the differences between cars much clearer. Results are updated four times a year, so any significant changes in a model's reliability become apparent quickly.

I have a 2003 P5 myself, so I'm especially interested in providing better information about these cars. So far the survey includes the 2002 and 2003, but other model years are getting close to the minimum sample size.

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, panel members receive full access to the results for free.

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

Vehicle reliability research

 

Updated results recently posted for the 2002 and 2003. They continue to require few repairs. Need more participants to include older model years.

The full set of results:

TrueDelta Vehicle Reliability Survey results

 

Updated results were posted recently. The 2002 and 2003 Protege5 continue to be "better than average," though the 2002 repair rate has increased a bit.

A big thanks to everyone who has been helping. We'll have further updates in May, August, and November, so additional participants would certainly be helpful. Especially for the 2002, where the sample size fell a few short of the minimum, so the stat for it is asterisked and not publicly visible.

We now have a separate results page for each model. The one of the Protege5:

Mazda Protege5 reliability comparisons

 

That's a lot of links to the same site.


Are you a spambot?

 

I'm not a bot. I conduct this survey, and update results every three months. When we have an update, I share that information with the community here.

The only way I can provide this information is if owners provide the data. They tend to only provide it if they know the survey exists. I'm very thankful that many have been helping out.

Just tried to unclutter the thread. Looks like "deleted by" entries are left behind...

 

cool. Thanks for the reply, and I'll try to help out with the clutter.

 

We have updated results for the Protege to include owner experiences through March 2009. In terms of successful repair trips per 100 cars per year:

2003: 44, better than average

2002-2002.5: 53, better than average

A big thanks to everyone who has been helping. We'll have further updates in August and November. With more participants, we could provide more precise information and cover all model years. This time around we were one response short of the minimum for the 2002.

Mazda Protege reliability comparisons

 

257 Protege owners now signed up. A good start, but more are needed to provide precise results for all model years.

Car reliability research

 

Updated results next month. Additional participants remain needed to cover all model years.

 

We have updated results for the Protege to include owner experiences through September 30, 2009. In terms of successful repair trips per 100 cars per year:

2003: 57, better than average

2002-2002.5: 79, better than average

2001: 179, worse than average

Very small sample size for the 2001, which might explain the much higher reported repair rate. Or these cars take a turn for the worse after 100k miles.

We've also introduced two new 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 2003, the percentage with no repairs is about 57, and the percentage of lemons is about 3.

Nada-odds and Lemon-odds car reliability stats

A big thanks, once again, to this forum and everyone who has been helping. We'll have further updates in February and May.

Mazda Protege reliability comparisons

 

284 Protege owners now signed up. A good start, but more remain needed to provide full results for all model years.

Not yet signed up? Details here:

Car reliability research

 

We have updated results for the Protege to include owner experiences through December 31, 2009. In terms of repair trips per 100 cars per year:

2003: 55, better than average

2002-2002.5: 75, better than average

2001: 146, worse than average

Very small sample size for the 2001, which might explain the much higher reported repair rate. Or these cars take a turn for the worse after 100k miles.

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 2003, the percentage with no repairs is about 52, and the percentage of lemons is about 7.

Nada-odds and Lemon-odds car reliability stats

A big thank you, once again, to everyone who has been helping. We'll have further updates in May and August.

Mazda Protege reliability comparisons

 

And now 303. The 1999-2001 are right at the minimum--additional participants would be especially helpful for these years.

Car reliability research

 

Had a couple repairs to my own P5 in April: another front wheel bearing, and the intake hose cracked causing the engine to run lean.

To provide an additional benefit, I recently enhanced the related repair history survey so that it can (optionally) be used as a personal car maintenance record for cars 2000 MY and newer.

As always, more participants would be helpful. Updated Car Reliability Survey results in May.

Car reliability research

 

We have updated results for the Protege to include owner experiences through March 31, 2010. In terms of repair trips per 100 cars per year:

2003: 75

2002-2002.5: 90

2001: 124

All are now about average. The repair frequency has been increasing recently for the 2002 and 2003.

Very small sample size for the 2001, which might explain the much higher reported repair rate. Or these cars take a turn for the worse after 100k miles.

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 2003, the percentage with no repairs is about 46, and the percentage of lemons is about 3.

Nada-odds and Lemon-odds car reliability stats

A big thank you, once again, to everyone who has been helping. We'll have further updates in August and November.

Mazda Protege reliability comparisons