2005 Jeep Liberty Turbo Diesel, Engine & Performance

Why is the diesel thirstiest? The Liberty's CDI doesn't represent the latest in turbodiesels. It suffers from clatter and vibration below 2000 rpm, where it spends a lot of its time. Idle is downright rough, like diesels from the pre-electronic fuel-injection days. It's the opposite of the Escape Hybrid, which can be perfectly still and silent at idle. Conversely, if you're into such things, the Jeep's CDI provides a tactile, big-truck clatter as an alternative to the Jetsonmobile put-put feel of the Escape and RAV four-banger.

Many of the best diesels sold in Europe have six-cylinder and V-8 engines, like BMW's 3.0-liter turbodiesel six, now in its second generation, and Mercedes-Benz's astonishing 4.0-liter turbodiesel V-8. New four-cylinder diesels in Opels (built by Fiat) and Hondas, for example, have made great strides forward, but the engines that continue to impress are the ones that power executive and luxury sedans.

Conversely, the Escape's hybrid engine is state-of-the-art. It's an Atkinson-cycle full-hybrid like Toyota's that'll run pure electric, but also uses the charged electric motor to give the SUV extra oomph for acceleration and passing. The tester was amazed at how quickly the gas engine recharged the electric motor. A gentle return-run down the drag strip nearly recovered the battery, and, after two runs, it was back up to full-charge, helping aid the engine with acceleration.

The Liberty suffers wheelspin launches, even with the four-wheel drive engaged. From there on, the power and torque diminish, with the wind going out of the turbodiesel's sails by 60 mph.