This is my post from another thread as I believe it's better to open a new one.

As we all talk and consider reliability on the forum, I'd like to try to bring some common sense and clarification on the issue.

The following are only my initial considerations in that regard.

It seems to me that everything gets down to reliability?

A thing that bothers me is that I’ve seen no definition for reliability?
What is the meaning of it?
How reliability is related to maintenance costs and/or to repair costs.
How an intensive ($$$) maintenance schedule reflects on reliability of a car?

Which car is more reliable:
- car A – spends $$$ amount every year on maintenance => never gets stranded on the road,

- car B- spends $ amount every year => fails ones in 6 years due to faulty knock sensor.

Or reliability is the cost to maintain and fix a car in % from the initial value of the car?

Example:

TB replacement:

- A6 – 2.3% (average)
- Subaru -1.3 % (average)

Is the Subaru as twice (or more) as reliable than A6?

Do we agree that the maintenance costs should be proportionally the same on cars with different price tags?

 

Comments?

 

funny you mention Subaru because my friend has a 02 Subaru wrx and i have my 02 a6 quattro and i have put more money into maintenance than he has and we both have about 90k for miles so, ive probably put 2100 in maintenance to his 1200 and that is for parts in each ( such as timing belts, cv boots and so on )so yeah but i still love my Audi to death thats why i will keep throwing money at it but i def want a tt in the future or maybe an Mitsubishi evo

 

http://en.wikipedia.org/wiki/Reliability_engineering

I dont think that maintenance costs are apart of reliabilty assessments. Something isnt more reliable just because the oil filter is cheaper etc.

Maintenance schedules is another issue because reliabilty concerns the ability of a system to perform over time. Maintenance schedules also define the factory determined reliabilty period.

For a car, the real purpose is to provide transportation. So a realiable car is the one that can do this most frequently. So if routine maintenance requires the car to be in the garage every other weekend, then you could say that it is unreliable becasue it is unable to perform. If parts fail but you can still drive the car or it is easy to fix, then the car is reliable. If parts fail and you need to rebuild the engine then the car is unreliable in that sense. However, you must consider a very large sample size to obtain reliable statistics. But to me it comes down to the the amount of time a car operates vs. amount of time car is unable to operate, on average.

Most consumer reports about car reliabilty may provide some valuable statistical information, but most of the assessments and conslusions are oversimplified. The real world is not exactly a controlled environment so there are a lot of variables to account for and hidden assumptions.

 

Actually this is a very interesting subject. In some respects and depending on the perspective one comes from, it may be a delicate subject to tackle.
I will comment, so at least you have one person interested in it.
I only quoted parts of your post, because you sort of hit the nail in the head in those parts.

Let's propose a common denominator, and that's the definition of reliability, as articulated by Merriam-Webster:
When it comes to cars, I believe that reliability should be the ratio between road dependability and the costs involved to maintain it.
To what extent do we rely on our cars?
I doubt there's anyone that when asked "What do you consider car dependability?" would say "I want to step in my car and find something wrong with it on a daily basis; I love to spend money on it to keep it driveable".
In my acceptance, car dependability should translate into "I want the ability to step in my car, turn the key and I'm on my way on a daily basis, with minimal expenses".

So to a quick first look, for the first quoted part I would say right away that Car B is more reliable, based on the minimality of expenses related to keeping it road dependable. And that's valid if Car A and Car B have similar price tags.
However, that would be more of a "horse blind" sort of approach.

If CarA has a price tag that's double than CarB, then CarA becomes the more dependable one by virtue of no breakdowns and price tag proportionality.

Therefore, yes I agree that maintenance costs should be judged based on price tag proportionality.
It would be not fair to say that a Honda is more reliable than an Audi just because its parts cost 2 times less than for the latter.
Hope I made some sense of what I tried to convey.

 

very interesting thread.....I had to do a right up back in Auto tech for this pertaining to reliablitity.

Car and Driver and Consumer Reports always rate Japanese cars the highest in reliablity. Our class instuctor wrote CR a letter asking how they came up with the reliablity numbers and they responded with an example:

A Japanese alternator typically lasts 150k miles on average compared to 75k miles on a GM car. First of all that is not always true. Also, factor in the cost of the alternator....the one for my 95 Lexus costs $400 while for my tahoe is about $115. I would rather replace my alternator twice for $230 then once for $400 on a Japanese car. This is why those magazines and publications are flawed. After owning two lexus', I will never own one again unless it is under warranty!! The parts for it are through the roof(way more than my old 2000 A6). For example, I had to replace the Idle control sensor on my lexus last month and it cost $470 just for the part and not to mention the top of the intake had to come apart to get it off!

Reliability is more related to maintance. I strongly believe that if you take excellent care of ANY make or model of car it will give you many years of trouble free reliablity.

 

I still dont see how the price of parts figures into reliabilty. Like I said before, a cheaper oil filter doesnt make a car more reliable. Cost should be another factor, separate from reliabilty. Reliability does not imply that something is cheap to maintain or that it is affordable to own. Cost and reliability should both be considered when purchasing a vehicle. If a part must be replaced twice as often, then the car will be off the road for twice as long and therefore is less reliable.

 

On my opinion the reliability should be a function of car care spending and availability on the road.
If a car A -demands xxx of $ to be available on the road
if a car B - demands x of $ to be available on the road

I'd assume there is a strait correlation between maintenance costs an reliability.

Consider this:

Car A - gets $3000 at 100k kim maintenance bill
Car B - gets $300 at 100k kim maintenance bill.

(A new Car A costs as twice as new Car B)

Would one suggest that the both cars are equitably reliable?

 

If you read the wiki link it states:

"Reliability engineering is an engineering field, that deals with the study of reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time.[1] It is often reported in terms of a probability."

so when you speak of reliabilty, you should speak about the chances of failure. If car A costs 10 times more to maintain then car B, and car A and car B fail at the same rate, then I would say that car A and car B are equally reliable. But the price of reliability for car A is 10 times more.

 

I'm wondering if (in your example) car A demands 10 times more maintenance spending then the car B=> do they have the same reliability?

If one states that car A costs 10 times more than the car B JUST for reliability reasons - then the moral is self-defined=> evident inferiority of design principles and abilities.

I believe we should focus on cars with different initial prices that offer different levels of consumers experience.