Mercedes-Benz has long been a proponent of
diesel engines, and its current BlueTec is so good that its quiet performance
and good fuel economy are sure to win over customers.
The GL350 has a 3.0-liter diesel V-6 with
210 horsepower. This engine delivers 400 pound-feet of torque at 1,600 rpm.
more torque, at 1,000 lower rpm, than the
V- 8 in the gas-powered GL450, and torque is most useful in acceleration and
Today’s high-tech diesels are clean, quiet,
and 20 percent to 40 percent more efficient than gasoline engines. They also
emit less carbon monoxide and carbon dioxide.
Because diesels have high combustion
temperatures, they produce more nitrogen oxide than a gasoline engine. The
Bluetec system injects a harmless solution of urea in the exhaust stream, and
that releases ammonia into a converter that changes 80 percent of the nitrogen
oxide into nitrogen and water.
The GL’s engine has four valves per
cylinder, dual overhead camshafts and piezo fuel injectors that spray fuel
directly into the center of each cylinder. A variable nozzle turbocharger adds
power and a counter-rotating balance shaft reduces vibration. The engine is
mated to a seven speed automatic transmission.
The GL has a 600-mile cruising range and it
can tow 7,500 pounds.
For 2010, the front of the GL was restyled
with a new grille, bumpers, fog lights and skid plates. The wheels are now
20-inch models with run-flat tires.
The GL has a 121.1-inch wheelbase and an
overall length of 200.6 inches. The long wheelbase results in room for three
rows of seats, and I carried six people without any crowding. The extra length
makes it somewhat hard to park in a shopping centre lot.