Mercedes M270 1.6 and 2.0 turbo petrol (A 180, A 200, CLA 200): problems, costs and what to check

A decent engine when the oil is changed on time, but a cold-start rattle or unusual engine noise on a 2015 car should stop the deal.

Updated 26 October 2026

At a glance

What it is: the Mercedes M270, a transverse four-cylinder turbo petrol, built from 2011 to 2019. It comes as a 1.6 (270910, 102-156 PS) and a 2.0 (270920, 184-218 PS) in the A-Class W176, B-Class W246, CLA C117 and GLA X156. The 7G-DCT dual-clutch gearbox has its own guide: 7G-DCT dual-clutch.
Main faults: the timing chain (the chain that drives the camshafts) stretches and rattles on cold start. Some 2015 cars can break a camshaft at a bad weld seam. The thermostat fails, coolant can leak from the expansion tank, and direct injection leaves deposits.
Reliability: 2/5. Chain and camshaft faults can end in engine damage, and the thermostat is a known weak point.
DIY: 1/5. Chain, camshaft and thermostat work is shop work, and diagnosis needs Xentry, the Mercedes diagnostic tool.
Prefer: a 2016-2018 car with full service records and a recent chain inspection.
Avoid: a cold-start rattle, a 2015 car with unusual engine noise, and a falling coolant level.

Known issues

Issue	Affects	Typical km	Repair cost
Timing chain stretch and cold start rattle	All M270, worst on 2012-2015 builds	About 80,000-130,000 km on early builds (kfz-dietrich)	No confirmed price
Camshaft breakage at the weld seam	2015 builds, mainly A-Class and B-Class	Not stated	No confirmed price
Thermostat failure	All M270	Not stated	700-800 GBP at a dealer, about half at a specialist (MBClub UK, 2020)
Coolant loss	All M270	Not stated	No confirmed price
Injector and intake valve deposits	All M270 with direct injection	Not stated	No confirmed price

Before you buy

Timing chain (scanner needed). Start the engine cold and listen for a metallic rattle for 1-3 seconds. Ask for Xentry live cam data and check for codes P0016, P0017 and P0011. Bad: a rattle, any of those codes, or a chain reported as slack. A jumped chain can destroy the engine.
Camshaft (no scanner). For a 2015 car, listen for unusual engine noise at idle and under load, and check for power loss and rough running. Bad: a noisy engine, or power loss and rough running on the test drive.
Thermostat (scanner needed). From cold, the engine should reach about 80 C within 10 minutes, and the live reading should sit between 95 and 105 C. Read codes P0128 or P1296. Bad: a temperature that stays low, overheating, or either code.
Coolant (no scanner). Check the level when cold and again after a few weeks. Bad: a falling level or coolant stains around the expansion tank.
Injectors and intake valves (scanner needed). Look for rough idle, misfires, power loss and higher fuel use. Bad: a misfire code or a rough idle.
Oil and service history (no scanner). Ask for oil change records. Long gaps between changes and short trips speed up chain wear. Bad: long gaps or no records.

Models with this engine

Brand	Model	Generation	Production years	Power	Engine codes	ADAC versions
Mercedes-Benz	A-Klasse	176	2012–2015	122–211 PS (90–155 kW)	270910, 270920	41
Mercedes-Benz	A-Klasse	176 facelift	2015–2018	102–218 PS (75–160 kW)	270910, 270920	82
Mercedes-Benz	B-Klasse	246	2011–2014	122–211 PS (90–155 kW)	270910, 270920	19
Mercedes-Benz	B-Klasse	246/242 facelift	2014–2018	102–211 PS (75–155 kW)	270910, 270920	147
Mercedes-Benz	CLA	117	2013–2016	122–218 PS (90–160 kW)	270910, 270920	76
Mercedes-Benz	CLA	117 facelift	2016–2019	122–218 PS (90–160 kW)	270910, 270920	149
Mercedes-Benz	GLA	156	2014–2017	122–211 PS (90–155 kW)	270910, 270920	48
Mercedes-Benz	GLA	156 facelift	2017–2020	122–211 PS (90–155 kW)	270910, 270920	105
Mercedes-Benz	GLA	247	2020–2023	163–224 PS (120–165 kW)	270910, 270920	15

In detail

Timing chain stretch and cold start rattle

The timing chain drives the camshafts. A hydraulic tensioner keeps it tight, and the chain wears.

Symptoms. A metallic rattle for 1-3 seconds after a cold start. Fault codes P0016 and P0017 mean the camshaft and crankshaft no longer line up; P0011 points to the cam adjustment.

Cause. The chain stretches and the tensioner rail wears. A leaking hydraulic tensioner lets the chain sag overnight and rattle at start-up. Long oil intervals and short trips speed this up. Early builds 2012-2015 are the most affected.

Which cars. All M270 engines. Revised components were fitted from mid-2015. kfz-dietrich describes cars built 2016-2018 as clearly more solid than 2012-2014.

Fix. Replace the full set: chain, tensioner, guide rails and adjusters.

Revised parts. Revised chain, tensioner and guide components from mid-2015. No part numbers are given in the sources.

Sources: kfz-dietrich, A-Class W176 problems, gebrauchtwagenberater, M270 problems, MBClub UK, M270/M274 camshaft faults

Camshaft breakage at the weld seam

Some M270 engines can break a camshaft because a weld seam was not made correctly. In the worst case it destroys the engine.

Symptoms. Unusual engine noise, power loss and rough running.

Cause. An incorrectly made weld seam on the camshaft.

Which cars. Model year 2015, especially the A-Class W176 and B-Class W246. gebrauchtwagenberater adds the CLA C117 and GLA X156.

Fix. Ask a Mercedes dealer to check the VIN for open campaigns.

Sources: gebrauchtwagenberater, M270 problems, mbpassion, M270 problems and maintenance tips

Thermostat failure

The thermostat sits at the bottom of the engine and has a built-in heating element.

Symptoms. The engine does not reach about 80 C within 10 minutes from cold. The live reading should be between 95 and 105 C and never below. Higher fuel use, irregular temperature control and overheating can follow.

Cause. The heating element and the electronics in the thermostat fail. Fault code P0128 announces the defect; kfz-dietrich lists P1296 for the same part.

Which cars. All M270 cars.

Fix. Replace the thermostat and drain and refill the coolant.

Cost. MBClub UK gives 700-800 GBP at a Mercedes dealer and about half that at a specialist (2020). gebrauchtwagenberater says a few hundred EUR (year not stated). kolesa.ru gives about 30,000 RUB for the thermostat part alone (2022) and says it sticks open in about 90% of failures.

Sources: MBClub UK, 2016 A-Class M270.910 reliability, MBClub UK, EML warning P06DA00 and P012800, gebrauchtwagenberater, M270 problems, kfz-dietrich, A-Class W176 problems, kolesa.ru, A-Class W176 used

Coolant loss

Coolant loss is common on these cars. The usual cause is a leaking expansion tank that degrades over the years.

Symptoms. A falling coolant level when checked cold. With a bad thermostat it can cause overheating.

Cause. A leaking expansion tank.

Which cars. All M270 cars. kolesa.ru says the tank cracks on cars older than five years.

Sources: gebrauchtwagenberater, M270 problems, mbpassion, M270 problems and maintenance tips, kolesa.ru, A-Class W176 used

Injector and intake valve deposits

Direct injection sprays fuel straight into the cylinder. Deposits form on the injector tips and the intake valves.

Symptoms. Power loss, higher fuel use, rough running, misfires and a rough idle.

Cause. Deposits from direct injection.

Which cars. All M270 engines with direct injection.

Fix. The sources give no repair figure. Fuel additives, occasional premium fuel, the correct oil and frequent oil changes are named as prevention.

Sources: gebrauchtwagenberater, M270 problems, mbpassion, M270 problems and maintenance tips, MBClub UK, 2016 A-Class M270.910 reliability

Maintenance

Oil. Change the oil on time. Long intervals, short trips and poor oil speed up chain wear and help injector deposits.
Coolant. Check the level when cold every few weeks. A falling level points to the expansion tank or the thermostat.
Chain. A cold-start rattle needs a chain inspection, not just a new tensioner.
Scanner. Before buying, have all control units read with Xentry and the chain correlation checked.