At what point does your car become so defect prone and unreliable that you just want to trade it in for any price short of theft?

Millions of consumers face this exact scenario every year: Some cars are simply worth more dead than alive, while others have issues so expensive and complex that you can't even find a willing buyer who will remove it from your life.

As a car dealer and former auto auction owner, I have seen thousands of these rolling money pits at wholesale auto auctions over the years. Cars that can't be easily figured out usually wind up in what we call, "wholesale heaven" in the car business: A place where a car can spend several months, and even beyond, before the dealership selling the vehicle is finally willing to let it go for not much back.

I wanted to help folks find good cars and avoid bad ones by using some objective measurement that went beyond what you can see or feel on a lot. So over these past two years, I have co-developed a new study, the long-term reliability index that focuses specifically on long-term reliability at every stage of a car's life. We now have nearly 400,000 vehicles in this database, all of which are independently inspected by professionals who are trained to figure out the overall mechanical condition of a vehicle.

We have done our best to remove all owner and brand related biases from this study. This is important because to be objective, we have to remove dealerships and individuals who may pretend that a bad cars is in good shape.

That's why we chose to have the vehicle's mechanical condition assessed only by mechanics and appraisers. Not an owner who may think that an improperly shifting transmission is in A-OK shape. There are also no franchise car dealers who may be trying to repackage the same type of vehicle as a good running retail car because they happen to be selling that particular brand.

All of the nearly 400,000 vehicles in this study come directly from independent dealers who don't have a stake in promoting a specific auto manufacturer. Eventually, by the end of next year, we will have over a million data samples that will help used car buyers drill down to specific models and powertrains for each brand.

But for right now, we would like to offer you a brief synopsis of the ten worst brands when it comes to overall long-term reliability. Feel free to peruse the 10 most reliable vehicles, 10 worst used vehicles, and the 10 most reliable brands while you're at it. There are a lot of surprises out there:

10. Kia: What hurts a lot of Kias in our study is that they were made by the old bankrupt Kia, and not Hyundai which is now in the middle of the pack. Older versions of the Kia Rio and Kia Sportage in particular have suffered head gasket issues which have helped drive down the overall long-term reliability of the Kia brand.
 

9. Mazda:  Mazda almost has a Jekyll and Hyde personality when it comes to long-term reliability. Three of the five worst vehicles in our study are Mazdas. Severe engine issues with the Mazda CX-7, along with powertrain issues with the defunct Mazda 626 and Mazda Millenia have plagued Mazda's standing in the used car market for a long time. However the MX-5 is a notable standout for long-term reliability.

8. Isuzu: Joe Isuzu may have been a great spokesperson for the now orphaned brand. Every single Isuzu model in our study has exhibited severe long-term transmission issues. Models equipped with the 3.2-liter engine also suffer from a near knocking engine sound that detracts from the ownership experience.

7. Suzuki: Great motorcycles. Decent SUV's. Horrific cars. The XL-7 and Grand Vitara are solid and the rare Aerio subcompact also offers a respectable showing. It's the Forenza and the Verona which come straight from the seventh circle of Dante's reliability inferno.

6. Audi: The top six are all European with luxury brands holding a lot of the territory. Nearly every older Audi model has reliability issues with only the Audi A8 and fairly recent Q7 bucking the trend.

5. Land Rover: These models should be parked underneath large Christmas trees because the dashboards usually offer a spectacle of festive lights. Not even Ford or BMW ownership could save Land Rover from remaining a reliability laggard.

4. Volkswagen: Glitch-ridden electronics, engine sludge, automatic transmission issues and an inaccurate timing belt replacement regimen for the 1.8 liter engine have all lead to VW's downfall in the USA. Turbodiesel models with manual transmissions have historically offered better reliability than the rest of VW's lineup.

3. Jaguar: The 4.0 Liter V8 in the Jaguar S-Type is shared with the Lincoln LS. Both models are jointly ranked among the ten-worst vehicles in our study due to long-term engine and transmission issues.

2. Smart: One model with poor reliability. Smart transmissions are notorious for bucking shifts. Sales are so low for off-lease Smart vehicles that Mercedes has developed an international car sharing program to use Smart vehicles called Car2go. Unfortunately, demand for using Smarts as car sharing vehicle was so low in the UK, that Mercedes recently pulled the program.

1. Mini: The Mini Cooper has been a sales success in the United States. Unfortunately, the automatic transmissions in 1st generation Mini (2001 to 2006) has led to a class-action lawsuit against BMW, the manufacturer of the Mini brand. Our study reflects this issue, and the excessive cost for replacing these CVT transmissions also remains an unresolved road block for many Mini owners.