Mileage Challenge 5.5: Final Thoughts

Beyond the numbers that we so diligently broke down yesterday, driving four different cars for six hours can be telling in many more ways than just fuel economy. Our editors share their thoughts on the cars and pick which car they’d log another six-hour trip in.

Mileage Challenge 5.4: The Results

Our latest mileage challenge had editors logging more than 300 miles each in three hybrids and a diesel: the 2010 Honda Insight, 2010 Mercury Milan Hybrid, 2010 Toyota Prius and 2009 Volkswagen Jetta TDI. We tallied up all the numbers and corrected for a brief photography stint between Legs 2 and 3. (Angling cars around for the camera — complete with rapid stops, starts and idling — has a way of dinging your mileage, and it’s not representative of real-world driving.)

The results were striking.

Mileage Challenge 5.3: Dizzying Displays

Most people think all of the advanced technology in today’s hybrid cars is under the hood. While automakers continue to enhance new engines, batteries and drivetrains, they’re also working on ways to wrangle the one factor they can’t control — the driver.

To gain maximum efficiency in a hybrid, a driver must be taught to drive properly so fill-ups are few and far between. In the crop of cars we tested on our mileage drive, there were a dazzling array of displays to teach people to drive as green as possible.

Mileage Challenge 5.2: Avenues and Interstates

Our latest mileage challenge took three hybrids — the Honda Insight, Mercury Milan Hybrid and Toyota Prius — and one diesel, the Volkswagen Jetta TDI, from Chicago to Fond du Lac, Wis., and back. The total distance came to just over 300 miles: The first 38 miles were in urban gridlock, the next 230 miles or so consisted of relatively open highway driving and the final 35 miles took place in afternoon interstate traffic.

As in our other mileage challenges, the ground rules remained largely the same: Four editors filled the tires to their recommended pressure, kept windows and sunroofs closed, drove as we normally would and switched cars at each leg to control for driving habits. But this being a challenge with hybrids there were some added things to look out for that could sway the results.

Mileage Challenge 5.1: Hybrid vs. Diesel

Despite gas prices averaging below $2.50 a gallon nationwide, hybrids and alternative-fuel vehicles are as popular as ever. The redesigned Toyota Prius is one of the country’s best-sellers, and Volkswagen’s TDI diesel was in short supply after it debuted at dealers earlier this year. With interest in these types of vehicles still high, we held another mileage challenge with the most popular of these cars and included both hybrids and VW’s most efficient diesel.

VW Diesels Doing Well Versus Hybrids

Automotive junkies know that modern diesel engines in fuel-efficient cars can be more fun to drive — while delivering high mileage — compared with modern hybrids. That’s why Volkswagen has relative hits on its hands with diesel versions of its Jetta sedan and wagon.

In July, VW sold 3,865 Jetta TDI sedans and 1,932 TDI wagons. Honda’s all-new Insight hybrid has been off to a slow start, posting another lukewarm month of sales for July: 2,295. Ford’s hybrid versions of the Fusion, Milan, Escape and Mariner totaled 5,353 sales in July.

However, the Toyota Prius set a sales record during a Cash for Clunkers-fueled July, with sales of 19,173. VW may have a ways to go to catch up to the Prius, but compared with other hybrids — and even other VW models, like the new Tiguan crossover (1,088 sold) and CC sedan (1,413) — diesel Jettas are doing very well.

The Jettas are the best example of what diesel engines can do in small, relatively affordable packages. Besides large trucks, most diesel offerings are found in German luxury cars and SUVs. The low price of diesel this summer also has to be taken into account, but perhaps all this will lead to other automakers bringing the technology to smaller cars.  

Recall Alert: Volkswagen Jetta

Volkswagen has issued a recall for 25,594 Jettas from the 2006-09 model years, according to the National Highway Traffic Safety Administration. The recall affects all models with a 2.0-liter four-cylinder engine; the fastening screw contact surfaces on the driveshaft cover plate may have been manufactured incorrectly.

The screws may not have been torqued properly during assembly and could loosen over time, resulting in a knocking sound during driving. If they loosen enough, the driveshaft could detach from the gearbox. A damaged gearbox housing can also leak oil.

Dealers will inspect the driveshaft screws and replace them, if necessary, for free. Owners can call Volkswagen at 800-822-8987 or NHTSA at 888-327-4236.