Petrol-electric C-Class is a surprisingly well-priced alternative to a diesel but not the greatest example of the new ‘PHEV’ breed

What is it?

The Mercedes C 350 e is another reason to weigh up the advantages of plug-in petrol-electric hybrid power over a conventional diesel engine in your next compact executive saloon.

Those reasons have been mounting of late. Counting the Volkswagen Passat GTE, Volvo V60 D5 Twin Engine, Audi A3 e-tron Sportback and BMW ‘iPerformance’ 330e, there are now plenty of ways for benefit-in-kind tax-paying drivers to combine premium-brand ownership with a sub-50g/km electrified powertrain and end up in a faster and more efficient company car for a similar monthly outlay to that of a mid-range diesel. This youthful niche of the saloon market is now full of cars priced at considerably less than £40,000 in some cases and might even offer value to a private buyer with the right kind of usage in mind.

Like the recently road-tested Passat GTE and unlike the Volvo V60, the C 350 e features an electric motor mounted in line with the combustion engine and upstream of a seven-speed automatic transmission. With only 80bhp of electric power and 6.2kWh of battery storage, the C-Class offers less zero-emission power and range than most of its competitors.

That said, the Merc’s relatively healthy 208bhp turbocharged 2.0-litre petrol engine makes the C 350 e the only four-door PHEV of its kind capable of a sub-six-second 0-62mph time. So exactly what kind of upper-echelon mid-size Benz is this?

What's it like?

First and foremost, this car appeals because it’s a well-equipped C-Class at an attractive price. Available from just under £39,000, the C 350 e will actually cost you less than an equivalent 94g/km C300h diesel hybrid C-Class if you’re eligible for the UK government’s ‘ULEV’ grant for ultra-low-emissions cars. For fleet drivers the tax saving the car delivers should more than offset the slightly higher monthly contract hire. And to sweeten the deal further, Mercedes even throws in Airmatic air suspension as standard.

The car’s interior is expensive-feeling, pleasant and solidly hewn. The packaging of the drive battery takes a sliver of boot space away immediately above the rear axle but it hardly makes a difference to the car’s practicality in everyday use. Rear seats that fold 40/20/40 come as standard and passenger space front and rear is very competitive for the class, with room for bigger adults in the back.

To drive, the C 350 e makes for a better limousine than it does a sports saloon. There are several drive modes to choose from, but even in its Sport and Sport+ settings the car's steering feels a bit rubbery and leaden off-centre and the air springs can struggle to maintain flat, steady body control, or conjure much of a sense of connectedness with the road surface. Those air springs also make for noticeable road roar over coarse surfaces.

Despite the promise of hot hatchback-level performance, the C 350 e never really feels fast, and when animated that 2.0-litre turbo petrol engine isn't particularly keen to rev. But at lower crank speeds and less hurried rates of progress the motor is quiet and well isolated, and the automatic gearbox and electric motor work well together to effortlessly preserve forward momentum.

Mercedes quotes a zero-emission range of 19 miles with a full drive battery, but during our testing the C 350 e would cover only 12 miles, on a mix of town and country roads, before the petrol engine joined in. That isn’t great electric autonomy: a Passat GTE will easily double that, as will a Mitsubishi Outlander PHEV.

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The limited size of the car’s drive battery, the limited available power of its electric motor (it’s potent enough at town speeds but struggles above 50mph) and the relative thirst of its 208bhp petrol engine also limit the real-world economy you might get from the car.

On short runs, better returns are possible, but on a typical 50-mile commute, where you might see 80mpg from some rivals, the C 350 e will return about 50mpg. Use the car like any other, decline to bother to charge it and drive it with absolutely no regard for the talent of its powertrain to ‘sail’ and regenerate energy while braking, and you’ll see fuel economy in the low 30s. 

Should I buy one?

Predominantly short-range motorists who like the idea of a refined, upmarket compact executive saloon with a zero-emission twist might. The C 350 e is actually quite competitively priced compared with Mercedes’ higher-end C-Class diesels, and for those who don’t do the mileages needed to see the benefit of a leggy oil-burner, it’s got plenty to recommend it.

That the car isn’t more competitively priced compared with the plug-in hybrid competition from BMW and Volkswagen may count against it with early adopters however, likewise that it doesn’t offer more robust and longer-lasting electric-only running.

Mercedes-Benz C 350 e Sport

Location Feltham, Middlesex; On sale now; Price £38,900; Engine 4 cyls, 1991cc, turbo, petrol, plus electric motor; Power 275bhp; Torque 442lb ft; Gearbox 7-spd automatic; Kerbweight 1780kg; 0-62mph 5.9sec; Top speed 155mph; Economy 134.5mpg (combined); CO2/tax band 48g/km, 7% Rivals VW Passat GTE, BMW 330e

Matt Saunders

Matt Saunders Autocar
Title: Road test editor

As Autocar’s chief car tester and reviewer, it’s Matt’s job to ensure the quality, objectivity, relevance and rigour of the entirety of Autocar’s reviews output, as well contributing a great many detailed road tests, group tests and drive reviews himself.

Matt has been an Autocar staffer since the autumn of 2003, and has been lucky enough to work alongside some of the magazine’s best-known writers and contributors over that time. He served as staff writer, features editor, assistant editor and digital editor, before joining the road test desk in 2011.

Since then he’s driven, measured, lap-timed, figured, and reported on cars as varied as the Bugatti Veyron, Rolls-Royce PhantomTesla RoadsterAriel Hipercar, Tata Nano, McLaren SennaRenault Twizy and Toyota Mirai. Among his wider personal highlights of the job have been covering Sebastien Loeb’s record-breaking run at Pikes Peak in 2013; doing 190mph on derestricted German autobahn in a Brabus Rocket; and driving McLaren’s legendary ‘XP5’ F1 prototype. His own car is a trusty Mazda CX-5.

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deeagusgee 21 July 2020

Too many problems

I bought a C350e sport nearly new in September 2017, 8,000 miles.  Have done little more than average motorway mileage since, now 60,000.  1st problem, starter motor worked loose just outside warranty and not long after MB official service resulting in juddering.  Replaced at cost near 800.  2nd problem, poor fuel economy nothing like ambitious figure MB claim.  3rd problem, Air suspension compressor has just failed and must be replaced.  Cost 720 plus VAT plus labour, approx 1200.  4th problem, I cant get rid of it fast enough.   

getmyauto 5 October 2016

Is this available in US

I only see 300 on MB site. Do you know its equivalence in US?
timsmith73 3 October 2016

This car is dangerous and should be recalled

I have owned the estate version of this vehicle for 10 months in the Netherlands. A large number have been sold here due to 7% BIK. The car has a habit of activating its e-mode limp home function even when driving at motorway speeds. This happened to me while i was driving at 130km/h on the 'fast' lane of a 4 lane motorway, the petrol engine shut off, e-mode was activated limiting the car to 60km/h. Apart from the rapid deceleration on a busy motorway, navigating across 4 lanes of traffic in limp mode was not safe.

The car has been with Mercedes for the last 3 weeks while they try and work out what is wrong with it.

Additionally the wiring loom in the car was replaced after 3 months, at the time Mercedes told me they had done that to 40% of the cars sold in the Netherlands. Advertised fuel economy is also nowhere near the manufacturer's claims, actually worse than a petrol variant of the same car without all the 'hybrid' technology.

Mercedes should recall all of these cars and fix the safety fault before someone dies.