The Mercedes E300 Bluetec Hybrid is based on the E-Class executive car, and is the company’s first diesel-electric model.
It combines the 201bhp 2.1-litre engine from the E250 CDI with a 27bhp electric motor and a seven-speed automatic gearbox to average 67.3mpg and just 109g/km of CO2 (in saloon form).
The estate is almost as efficient, managing 64.2mpg and 116g/km, although all these figures are possible only with the no-cost optional 16-inch alloys.
The standard-fit 17-inch wheels increase the saloon’s emissions to 111g/km and its average consumption to 65.7mpg, while the estate's stats are revised to 119g/km and 62.8mpg.
What’s the 2012 E300 Bluetec Hybrid like to drive?
If you tread very lightly on the accelerator, the E300 can run on electric power alone for short periods. Alternatively, put your foot down hard and the electric motor assists the engine, providing strong performance.
Sadly, the engine sounds quite gruff when it’s revved hard, and while it’s near-silent at a steady cruise – and can even shut down altogether – it send shudders through the cabin whenever it fires back into life.
This is a pity, because the E300 is good at soaking up bumps in the road at all speeds, and is generally refined on the motorway, keeping out most wind and road noise.
The E300 also feels very stable at speed, although it’s not as agile as many rivals in the corners.
What’s the 2012 E300 Bluetec Hybrid like inside?
Aside from a couple of readouts on the dashboard that show how the hybrid system is working, it looks like any other E-Class from behind the wheel.
The dashboard falls a little short of the class-leading BMW 5 Series in terms of perceived quality and ease of use. However, the driver’s seat is part-electric and there’s a huge range of adjustment, so you’ll have no trouble finding a comfortable position.
The rear is equally impressive, with space for a couple of six-footers.
What’s more, Mercedes has managed to fit the electric motor's batteries under the bonnet, so they don’t eat into the boot space as they do in many hybrids.
Should I buy one?
The E300 Bluetec Hybrid is the most efficient car in its class; even BMW’s 520d Efficient Dynamics looks a little dirty by comparison, let alone other E-Class models and petrol-electric hybrids such as the BMW Active Hybrid 5.
True, the E300 isn’t as refined as a 520d ED, but those tiny emissions and the fact it isn't subject to the 3% surcharge that's usually applied to diesels make it cheaper to run as company car. We would wait for the revised E-Class, though, which goes on sale in the new year.
Read the full What Car? Mercedes E-Class review
BMW 520d Efficient Dynamics
What Car? says…
By Steve Huntingford
Our reviews are based on hard data and thorough testing in the real world.
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