A W177 Mercedes A-Class (2018 on) is the one to buy once you've seen its instrument display working, while a W168 (1998 to 2005) is best left alone, as its automatics fail between 40,000 and 80,000 miles.
13 known faults, 8 rated high severity in our database; owners report 45.5 mpg, 83% of the official figure. Everything below is built from that data and the archived owner history, not from a press car.
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Check a Mercedes-Benz A-Class advert (free) →Go for a W177 (2018 on), because its serious known fault is an instrument display that goes black on 2019 and 2020 cars, sometimes when they're almost new, leaving you with no speed, fuel or gear readout. Start one more than once and make sure the display comes on every time. If it's a 7G-DCT dual-clutch automatic, it can judder and shift jerkily as the clutches wear between 50,000 and 100,000 miles, so feel for that when pulling away.
A W176 (2012 to 2018) is a bigger gamble, and a diesel's the lesser risk, since the 1.6 and 2.0 turbo petrols (M270) stretch their timing chains between 50,000 and 100,000 miles. Any W176 can let water into the boot and rear footwells through failing rear vent flaps, and cars up to 2017 need proof of the steering column spring recall, which stops the driver's airbag going off by itself.
A W169 (2005 to 2012) with a manual gearbox is the one to consider, because the Autotronic CVT's internal control unit fails between 60,000 and 120,000 miles and leaves the car in limp mode. Rust's the other deal-breaker on these: door bottoms and tailgates rot through, and there were numerous reports on 2005 and 2006 cars, so look at both before anything else.
Don't buy a W168 (1998 to 2005). Its automatics fail between 40,000 and 80,000 miles and need a new gearbox, diesel glow plugs fail and then snap as they're being taken out, petrol cars' fuel filler pipes crack and leak petrol into the back when the tank's overfilled, and the multi-section steel sunroof jams when one of its motors dies. Rust gets into the door bottoms, tailgate and A-pillars too.
On a W176, the 1.6 and 2.0 turbo petrol (M270) is the engine to be careful with: its hydraulic tensioners leak and the timing chain stretches between 50,000 and 100,000 miles. Leave it and the plastic guides wear until the chain skips a tooth, bringing an engine warning light, rough running or a misfire. A metallic rattle lasting several seconds from a cold start is the early warning, so don't buy one that makes it.
A diesel is the lesser-risk W176, as that chain fault belongs to the petrol, but it still needs checking. The Renault-sourced 1.5 CDI has a cambelt due every 60,000 miles or 5 years, so ask for the receipt. Mercedes diesels registered between 2011 and 2015 were recalled for an emissions software update, and one 2015 A 220 CDI spent 11 weeks at a dealer with an engine control unit that kept faulting.
Avoid the Autotronic CVT fitted from 2004 to 2012. Speed sensor circuits inside its sealed control unit break down between 60,000 and 120,000 miles, putting a Transmission Visit Workshop warning on the dash and dropping the car into limp mode. The 7G-DCT dual-clutch automatic used since 2012 isn't trouble-free either: it can judder at low speed as its clutch packs wear, and control unit failures bring harsh changes from 2nd to 3rd.
Every W168 automatic is a risk, with failures needing a new gearbox between 40,000 and 80,000 miles, and its diesels' glow plugs fail between 60,000 and 100,000 miles, worst on cars used for short runs from cold. The semi-automatic 170 CDI has had clutches slip after 40,000 miles and one fail at 21,000, and manual gearbox failures have been reported. On a W169 diesel manual, a dry clutch spline can make the car stick in gear at a standstill.
Ask the seller not to start the car before you get there. On a W176 1.6 or 2.0 turbo petrol, a metallic rattle for several seconds after a cold start means the timing chain's stretched. On a 7G-DCT automatic, pull away several times and feel for judder or a lurch, which is worse when cold, and listen for a clunk as it goes into Park, Neutral or Reverse.
Lift the boot floor and feel the rear footwell carpets on a W176, since failing rear vent flaps let water that the back wheels splash up get into the load area, from where it runs forward. Damp carpets, a musty smell or a flooded spare wheel well give it away. On any A-Class up to 2012, check the door bottoms, tailgate and A-pillars for bubbling paint or holes, and on hatchbacks look closely at the tailgate's weld seals.
A W169 Autotronic that shows a workshop warning, loses drive or holds one ratio points to the control unit fault, though make sure the Tipfunction isn't simply locking it in the ratio you've picked. On a W168, open and close the steel sunroof fully while listening for grinding and watching for skewed panels, and sniff for petrol inside. On a 2019 or 2020 W177, restart it and check the instrument display comes on each time.
Ask for invoices showing the CVT fluid's been changed on a W169, and the cambelt on a 1.5 CDI every 60,000 miles or 5 years. Get proof of the steering column spring airbag recall on 2011 to 2017 cars, the brake booster vacuum line and airbag recalls on a W176, the transmission software update on 2018 and 2019 W177s, and the brake master cylinder recall on 2000 and 2001 W168s.
Paste the advert into the free check and it runs these against the listing, the MOT history and the DVLA record before you travel.
A W168 isn't worth the risk, as its automatic gearboxes fail between 40,000 and 80,000 miles and need replacing, with the car stuck in 2nd gear or losing power as it moves off. Before blaming the gearbox for a weak getaway, rule out a sticking stop light switch, which tells the engine to drop to tickover. On an automated manual that won't take up drive, a loose orange connector under the gear lever shroud can be to blame.
Diesels have glow plugs that fail between 60,000 and 100,000 miles and snap as they're being taken out, and injectors have failed on diesels after 6 to 7 years. Petrol cars suffer cracked fuel filler pipes that let petrol into the back if the tank's overfilled, and fuel pipes weep at the bulkhead on 6-year-old cars. The multi-section steel sunroof jams solid when one of its two motors fails and the other drags the panels out of line.
Rust attacks the A-pillars, where the plastic front wings rub through the paint as they expand and contract, and it gets into door bottoms and tailgates too. Rear trailing arm bushes have failed on early cars, and they're an MOT failure point, while early anti-roll bar links can need swapping for the later modified type. The steering column's universal joints wear, the ignition coil block can crack and let moisture in, and power steering pumps have failed.
It leans and runs wide on tight corners with adverse camber, it'll wander between lanes on the motorway if you don't concentrate, and the ride is poor. Don't drive it through floods, as low-set parts such as the power steering pump are exposed. The wipers are set up for left-hand drive, so they miss a strip on the right of the screen. Ask for proof of the brake master cylinder recall on 2000 and 2001 cars and the wiper arm recall on 2002 and 2003 cars.
Real-world economy on this generation: Mercedes-Benz A-Class 42.0 mpg.
A W169's Autotronic CVT isn't one to trust, as its internal control unit fails between 60,000 and 120,000 miles, bringing up a workshop warning and cutting drive. One owner's 2011 A 160 lost drive on and off at 37,538 miles and paid £84 for a diagnosis, then more than £800 to have the gearbox speed sensor module repaired. Further CVT failures hit a 2007 A170 at 27,500 miles and a 2008 A180 at 56,000 miles, the latter having missed its fluid change at 4 years or 37,000 miles.
Rust's the W169's other big problem, with door bottoms and tailgates rotting through: there were numerous reports on 2005 and 2006 cars, one 2006 A200 Turbo's door bottoms had rusted by 25,500 miles, and a 2007 car's rusted through. Failing weld seals on hatchbacks let rust in early. On diesel manuals, the clutch spline loses its grease between 40,000 and 80,000 miles, so the car sticks in gear if you hold the clutch down at a standstill.
Diesels used for short runs from cold can have glow plugs seize in the cylinder head as condensation corrodes them. Braking hard and late for speed cushions can damage the front suspension, and one 2009 A160 Autotronic's strut top mounts clunked. Brake discs have lasted roughly 3 years or 25,000 miles before dealers called for new ones, and a 2010 A180 kept failing brake light switches, throwing up false ESP warnings.
One-off electrical faults include an ignition steering lock module that cost one owner £643.20 to replace, a driver's window that opens and shuts when it likes, and repeated fuel sender pump failures on an A150. One 2010 1.5 petrol's engine died when ECO stop-start cut in, then its electrics went off for 10 to 15 seconds as it restarted. Blocked drains in the bulkhead vent well can soak the satnav and kill it.
Real-world economy on this generation: Mercedes-Benz A-Class 42.0 mpg, Mercedes-Benz A-Class 47.4 mpg.
A W176 isn't a straightforward buy, because the 1.6 and 2.0 turbo petrols (M270) stretch their timing chains between 50,000 and 100,000 miles, and any version can let water into the boot. On the petrols, leaking tensioners let the chain rattle for several seconds on a cold start, and if nothing's done it can jump a tooth, bringing an engine warning light and a misfire.
The water comes in through one-way vent flaps between the load area and the rear bumper, which fail between 40,000 and 80,000 miles and let spray from the back wheels soak the boot and rear footwells. The repair means removing the bumper and flaps, and one owner of a 2013 car was charged £110 just for the dealer to diagnose it. Red paint on 2012 to 2015 cars, Juniper Red included, can shed its clearcoat.
The 7G-DCT dual-clutch automatic can judder at low speed and change gear jerkily as its clutch packs wear, and one May 2013 A200 developed a reverse gear fault and jolted as it pulled away cold. A 2013 A 180 needed a new turbo at 10,000 miles and another at 20,000 miles, and a 2015 A250 4Matic refused to start with a 4Matic unavailable warning, with no parts to be had.
Check the recall paperwork, since the W176 has several: the steering column spring that can set off the driver's airbag, front passenger airbags that can fail to deploy, a driver's airbag housing that can break up in a crash, a brake booster vacuum line that can come apart, and an extra fuse for the starter circuit. Diesels registered between 2011 and 2015 also got an emissions software update. It earned five stars from Euro NCAP.
Real-world economy on this generation: Mercedes-Benz A-Class 47.4 mpg, Mercedes-Benz A-Class 44.6 mpg.
The W177's main known fault is a digital instrument display that won't switch on, which has happened on 2019 and 2020 cars anywhere up to 10,000 miles and leaves a black screen with no speed, fuel or gear information. One 2019 A 220 lost its display a couple of days after being bought, and an ex-demonstrator A250 bought at 3,500 miles kept failing to switch it on.
On 2018 and 2019 cars, the transmission control unit's software was recalled because it could stop the car shifting into Drive or Reverse, so check the update's been done. On a 7G-DCT dual-clutch automatic, the same judder and jerky shifts as the older car's can show up as its clutches wear between 50,000 and 100,000 miles, so pull away gently a few times on the test drive.
One owner listed a string of electronic faults: Speed Limit Assist showing the wrong limit, Active Lane Assist braking for shiny bitumen, streams of water and bus stop markings, proximity sensors sounding for cars that had already gone past, a driver's seat that jumps back to its easy entry position when you switch on, and a software update that stopped personal points of interest warnings. There was a plastic rattle from the back too, and the car spent three weeks at the dealer.
Real-world economy on this generation: Mercedes-Benz A-Class 44.6 mpg, Mercedes-Benz A-Class Saloon 48.8 mpg.
Sellers rarely admit these faults outright
Paste any Mercedes-Benz A-Class advert and we check it against the faults, the MOT record and these figures in seconds.
Check an advert now (free) →Owners report 45.5 mpg across the Mercedes-Benz A-Class engines with data, about 83% of the official figure, from 1,194 submissions.
Mercedes-Benz A-Class Real MPG by engine →The W177 drives well, and its ride's excellent. It's been on sale since 2018, so it's the newest of the four A-Class generations, and it's the one to take out on a proper test route, rough roads included, rather than a quick lap round the block.
Inside, the W177's cabin looks modern, with a futuristic multimedia system in the middle of it. It's worth sitting in one for a few minutes before you drive it, getting the seat where you want it and working out how the screens and controls are laid out, because that's the part you'll deal with every day.
A W177 Mercedes A-Class (2018 on) is the one to buy once you've seen its instrument display working, while a W168 (1998 to 2005) is best left alone, as its automatics fail between 40,000 and 80,000 miles. Our database holds 13 known Mercedes-Benz A-Class faults, 8 rated high severity, and the sections above say which generation and engine carry them.
Go for a W177 (2018 on), because its serious known fault is an instrument display that goes black on 2019 and 2020 cars, sometimes when they're almost new, leaving you with no speed, fuel or gear readout. On the fault record the W177 (2018 on) carries 1 known fault against 5 on the W168 (1998 to 2005). Each generation's section above gives the detail. Mercedes-Benz A-Class faults by generation.
Ask the seller not to start the car before you get there. Read the MOT history for repeat advisories and ask for invoices for any work the seller mentions. Then paste the advert into the free check, which reads it against every known Mercedes-Benz A-Class fault before you travel.
Owners report 45.5 mpg on average, about 83% of the official figure, from 1,194 submissions. Belt (1.5 DCI, 1.5 CDI, OM607, K9K): 60,000 miles or 5 years, whichever comes first, so budget for it if the history does not show it done. The known faults page lists a rough repair cost against each fault. Mercedes-Benz A-Class Real MPG by engine.
If you used the Honest John car-by-car reviews before the site closed in 2026, this is where the Mercedes-Benz A-Class buying advice now lives. It is written from the archived owner reports and model notes (archived page, 113 items read for this model), our own known-faults database, the confirmed service intervals and the Real MPG figures. Every number on the page comes from that data, not from the text. The same data feeds our free advert check.
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The Mercedes-Benz A-Class is one decision. Reading the advert, the history and the seller are the rest, and these cover them.
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