Engines · Mercedes-Benz
Mercedes M272 V6 petrol common problems
The M272 is a naturally aspirated 90-degree V6 petrol in 2.5, 3.0 and 3.5 litre sizes, with an aluminium block, four camshafts on chains and a balance shaft between the banks. It replaced the M112 from 2004, gained a direct-injection CGI version in the 3.5, and was succeeded by the M276 from 2011. It was widely used, including in the W203 C-Class and W211 E-Class, and is otherwise a smooth, strong engine.
Common problems and what to look for on the M272
The known issues most worth checking when you view a car with this engine. None of them means a car is a bad buy, but they're worth knowing about before you buy, and a good history often shows they've been dealt with.
Balance shaft gear wear on early engines
What to look for: Check that the engine warning light comes on with the ignition and goes out once running, and listen for rough running when cold. Ask for the engine number (stamped on the block and often on the service paperwork) or for a Mercedes dealer or specialist to confirm it from the VIN. Ask for invoices if the balance shaft has been replaced. Have the fault memory read if you can.
Why it matters: On engines with serial numbers before 30 468993, built before about October 2006, the gear on the balance shaft sprocket, which also drives the right-hand bank's camshafts, can wear early. The right-hand camshafts then drift out of step, setting the warning light with fault codes 1200 or 1208, then rough running. Mercedes changed the sprocket material from October 2006 production, so later engines are not affected by this wear. The repair is a new balance shaft, a big job because it sits inside the block, so an early engine with the work on invoice is in a good position.
Broken intake manifold flap lever
What to look for: On the drive, accelerate from low revs in a high gear. A flat spot or loss of pull at low and medium revs, or a rough idle, is what to note, along with the engine warning light. Ask whether the intake manifold or its flap lever has been replaced.
Why it matters: The variable-length intake manifold is worked by a small plastic part that can break, helped by oily deposits from the crankcase ventilation stiffening the flaps. Typical fault codes are P2004, P2006 and P2187. Mercedes supplies only the complete manifold, while metal replacement parts are also used by specialists, and the manifold should be cleaned at the same time. It is a known, contained repair.
Oil seeping from the cam plugs at the back of the heads
What to look for: With a torch, look at the back of the engine where the cylinder heads meet the bulkhead, and below them on the gearbox bell housing. Wet, oily residue there is the sign. Ask whether the cam plugs have been replaced.
Why it matters: Engines built before June 2008 used plastic expansion plugs at the back of the cylinder heads that can let oil seep past. Improved plugs were introduced in June 2008, and replacing them is a straightforward job. A small seep isn't serious but is worth fixing before it drips onto the exhaust or wiring.
More known issues, covered in the full guide for each car
- Camshaft timing warning light on later engines
Cars with the M272
- Mercedes-Benz C-Class W204: C230 and C280 (2007 to 2009) and C350 petrol (2007 to 2011)
- Mercedes-Benz CLK C209: CLK280 and CLK350, 2005 on
- Mercedes-Benz CLS C219: CLS350, including the direct-injection CLS350 CGI
- Mercedes-Benz SLK R171: SLK280 (later SLK300) and SLK350
- Mercedes-Benz SL R230: SL350 from 2006 (268bhp, then 311bhp from 2008)
- Mercedes-Benz E-Class W212: E350 petrol V6 before the 2011 switch to the M276
- Mercedes-Benz M-Class W164: ML350 V6 petrol
- Mercedes-Benz S-Class W221: S280 3.0 V6 and S350 petrol
- Mercedes-Benz Viano W639: 3.5 V6 petrol, from October 2004
A pre-purchase inspection guide for your car
The CrankSight guide is a pre-purchase inspection (PPI) you do yourself, written for the exact model and generation you're viewing. It walks you round the car on your phone, with every check for that version, engine included: what to look for, where to find it, and what anything you find is likely to cost. As you go it builds an assessment of that car, and if you view more than one, it lines them up side by side.
£29 for the model, used on as many cars as you like, delivered within 72 hours or your money back.
General points for the engine, last checked October 2026. Every car is different, so treat this as a guide to what to look at, not a verdict on any car. CrankSight is independent and has no connection with any manufacturer.