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BMW 1 Series: N20 2.0L turbo timing-chain guide failure (125i F20)

N20 2.0L turbo timing-chain guide failure (125i F20) is a common engine fault on the BMW 1 Series on the 2011–2016 cars, and we rate it critical. Putting it right costs $2,500 to $4,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 50 documented faults on the BMW 1 Series.

Vehicle
BMW 1 Series
Engine
N20
Years
2011–2016
Fuel
petrol
System
Engine

This page covers the BMW 1 Series as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All BMW 1 Series faults50 documented faults on this model

What you are looking at

The front of a dual overhead camshaft engine with the timing cover removed, exposing the timing chain and sprockets.Example of the part — not this vehicle

The front of a twin-cam engine with the timing cover off — chain, sprockets and guides.

Logansenf · CC BY-SA 4.0 · Wikimedia Commons

What goes wrong

The 125i's 2.0L turbo four (N20), especially 2011 to early-2015 builds, wears its timing chain and plastic guides prematurely. Broken guide fragments fall into the sump and can clog the oil pump; the chain stretches and, worst case, skips or snaps, causing catastrophic valve-to-piston damage. The warning is a marbles-in-a-tin rattle for a second or two on cold start. This is a critical, must-check fault on any N20 125i.

What you would notice

  • Rattle like marbles in a can for 1-3 seconds on cold start
  • Whine at 1,500-2,500 rpm
  • Timing/camshaft correlation codes
  • Plastic flakes in the oil

How to check it

Where to look. Timing chain and plastic guides at the front of the 2.0L engine

Insist on a cold first start and listen for a rattle from the front of the engine. Ask whether the timing chain, guides and tensioner have been replaced with updated parts and scan for correlation codes. Avoid a 125i that rattles on cold start without a documented chain job.

Parts involved: Timing chain, Turbocharger.

What it costs to put right

$2,500 to $4,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Has the timing chain and guides been replaced?”
  • “Does it rattle on cold start?”

Now check the BMW 1 Series you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

  • Motronix – BMW N20 Timing Chain Failure guide
  • Atlantic Motorcar – BMW N20 Timing Chain Problems

BMW 1 Series buyer questions

Is n20 2.0l turbo timing-chain guide failure (125i f20) serious on a BMW 1 Series?

We rate it critical and common on the BMW 1 Series. The 125i's 2.0L turbo four (N20), especially 2011 to early-2015 builds, wears its timing chain and plastic guides prematurely. Broken guide fragments fall into the sump and can clog the oil pump; the chain stretches and, worst case, skips or snaps, causing catastrophic valve-to-piston damage. The warning is a marbles-in-a-tin rattle for a second or two on cold start. This is a critical, must-check fault on any N20 125i.

How much does it cost to fix on a BMW 1 Series?

$2,500 to $4,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which BMW 1 Series years are affected?

Our research records this fault on the 2011–2016 BMW 1 Series. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Insist on a cold first start and listen for a rattle from the front of the engine. Ask whether the timing chain, guides and tensioner have been replaced with updated parts and scan for correlation codes. Avoid a 125i that rattles on cold start without a documented chain job. Look here: Timing chain and plastic guides at the front of the 2.0L engine