Hot. Too hot. I'm standing by the side of the road at Badwater Basin in Death Valley. I think I can hear myself sweating. The mercury is topping 100 degrees Fahrenheit and the sun is just about to dip behind Telescope Peak in the west. The shadow of the mountain creeps across the salt flat, casting a five mile shadow towards the deserted road, finally drenching the silver grey Mercedes with relative cool. I can't see another soul. I haven't seen another car for seventy miles since I turned off the US395 at Lone Pine. Sometimes you need your car to be there for you.

The Mercedes E220CDI is just that car. Get in, fire the four-pot diesel engine up and the air conditioning atomises the beads of sweat forming on your brow in seconds. The radio is playing some country dirge about a guy who lost his wages in Las Vegas. I switch the source over to accept input from my iPod and turn the three-pointed star on the bonnet towards Vegas, some eighty miles away.

Xenon lights cut a pool of bluish light in the inky blackness. A coyote scuttles across the road ahead, disappearing into the sagebrush and scrubby, stunted creosote bushes. Joshua trees dot the horizon as if in supplication. I glance down at the speedometer. If there was a local sheriff anywhere around here, I'd probably get a night in the cooler but in Death Valley speeds are checked by aircraft and when the sun goes down, the planes retire too. If there was anybody around to see it, this car would likely pass unnoticed, despite not being officially imported to the US, where the Range begins with the larger E320CDI. High quality but low key is how its owner describes it.

"The E220CDI isn't a car that grabs your attention right away. It doesn't do superficiality very well."

Mercedes has certainly come a long way very fast in terms of quality. Sitting in the E220 CDI, it's tempting to recall bulletproof Mercs of the past but as recently as 1998, Mercedes seemed to be losing its way a little. Customers complained of inconsistent build quality, the A-Class had its teething problems and the S-Class was starting to look a little old. The traditionally crystal clear brand values dulled. If this represented a latter-day nadir for the Stuttgart company, the turnaround has been swift. 2000's C-Class Range was well received, quality problems evaporated as manufacturing issues were ironed out. More recently, the SLK then the CLS were introduced to rave reviews and the E-Class now generates routinely BMW-bashing headlines.

Although it's possible to push the design envelope with those low volume image building models at the fringes of your model Range, when it comes to the core models - C, E and S class, Mercedes have got it taped and the opposition licked. The E-Class still represents the star around which the entire Mercedes-Benz firmament revolves, the model Range which has shifted nearly a quarter of a million units worldwide. The E220CDI is a supporting player, a foot soldier in the E Class success story but no less impressive for that.

Seventy miles out of Las Vegas it's possible to see the 41.5 gigacandela power light of the Luxor Hotel shining straight up to the heavens, acting as a visual marker in the desert night. The E220CDI still has over half a tank of fuel left which, in a quick bit of mental arithmetic, works out at 475 miles Range available. I do the maths and then prod the column stalk to bring the Range up on the computer. It reckons I have 420 miles. Maybe I need to easy up on the throttle to bring the car back towards its 44.8mpg combined fuel figure. I blame the lousy quality of American diesel and keep it planted. Back in Blighty, where we get better fuel, this car will sprint to 60mph in 8.4 seconds and keep going until 141mph. It'll also chug out just 167g/km of carbon dioxide, less than a Focus 1.8 Zetec.

Saving the planet isn't the first thing that comes to mind when entering Vegas, where millions of light bulbs turn night into day. I duke it out with the obscene superstretched Cadillacs and rented by the hour Vipers on the Strip for a while before heading north through down-at-heel neighbourhoods to return the car to its keeper at Nellis Air Force Base.

Mercedes took extensive measures to improve the quality of this E-Class, introducing more advanced technology across a number of its systems but it's not immediately apparent that the current model is such a heavily revised vehicle. True Merc anoraks may spot the front bumper, v-shaped grille and revised headlights but that's about it externally. Inside, it's more of the same with a revised steering wheel and climate control panel being about the size of it.

Under the skin, it's a different story. Handling and steering have been improved and the adaptive braking system has been borrowed from the S-Class. This hydraulic dual-circuit braking set-up provides better safety and comfort features. Safety is a standout E-Class feature and the latest models feature the PRE-SAFE system which primes the seatbelt and airbag if it thinks the car is about to be involved in a collision. The NECK-PRO head restraints move forward within milliseconds of a rear shunt, protecting the driver and front passenger from whiplash injuries. Flashing brake lights are also featured, illuminating during particularly heavy braking.

I park the car at the fence line at the end of the runway and watch a pair of F-117 Nighthawks blast off into the Nevada sky. The car has to go back and I'll carry on the rest of my journey in an Alamo rental box. Sometimes it takes this sort of perspective to appreciate deeply ingrained quality. The Mercedes E220 CDI might talk quietly but there's genuine depth of character here. Maybe it takes a city as superficial as Vegas to appreciate that.

TOP 5 E CLASS DEALS

The results below show the top E CLASS deals on buyacar

	Mercedes-benz E Class E220 CDI Executive Nav 4dr Tip Auto Spec edn Saloon
	ETR	Mthly £501	Saving £3,596	Price £27,194
	Mercedes-benz E Class E220 CDI Executive Nav 4dr Spec edn Saloon
	ETR	Mthly £472	Saving £3,461	Price £25,814
	Mercedes-benz E Class E220 CDI Avantgarde 5dr Tip Auto Estate
	ETR	Mthly £584	Saving £4,017	Price £31,443
	Mercedes-benz E Class E220 CDI Avantgarde 5dr Estate
	ETR	Mthly £556	Saving £3,882	Price £30,088
	Mercedes-benz E Class E220 CDI Classic 5dr Tip Auto Estate
	ETR	Mthly £536	Saving £3,781	Price £29,079

typical 11.36% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000