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BMW 1 Series: N20 2.0T oil filter housing gasket leak (125i)

N20 2.0T oil filter housing gasket leak (125i) is a common fluid leaks fault on the BMW 1 Series on the 2011–2019 cars, and we rate it major. Putting it right costs $400 to $1,300 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
2011–2019
Fuel
petrol
System
Fluid Leaks

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

No photograph available

We do not hold a verified photograph of the Intake manifold or Turbocharger yet. We would rather show none than show a picture of a different part.

What goes wrong

The oil filter housing gasket is a well-documented failure point on the N20 2.0 turbo petrol engine fitted to the F20 125i. The rubber gasket hardens and contracts through heat cycling, allowing oil to seep past the housing flange. Access requires partial removal of the intake manifold due to a hidden fastener, making this a labour-intensive repair despite the low parts cost. Oil leaking onto the serpentine belt poses a secondary failure and fire risk. The NHTSA TSB catalogue includes documentation of this failure mode on N20-family engines.

What you would notice

  • Oil staining or puddle forming under the front-centre of the engine
  • Burning oil smell during and after driving
  • Visible oil seeping from the lower engine block near the filter housing
  • Oil level dropping between scheduled service intervals

How to check it

Where to look. Lower engine block, oil filter housing flange

  1. Inspect the oil filter housing area on the engine block for oil seepage, residue, or staining.

  2. Trace any oil tracks to confirm the housing is the source rather than the sump gasket.

  3. Check the serpentine belt for oil contamination.

  4. Ask for service history and note whether the repair has been done previously.

Parts involved: Intake manifold, Turbocharger.

What it costs to put right

$400 to $1,300 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 oil filter housing gasket been replaced?”
  • “Is there any oil leaking or is oil consumption occurring between services?”

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 published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

BMW 1 Series buyer questions

Is n20 2.0t oil filter housing gasket leak (125i) serious on a BMW 1 Series?

We rate it major and common on the BMW 1 Series. The oil filter housing gasket is a well-documented failure point on the N20 2.0 turbo petrol engine fitted to the F20 125i. The rubber gasket hardens and contracts through heat cycling, allowing oil to seep past the housing flange. Access requires partial removal of the intake manifold due to a hidden fastener, making this a labour-intensive repair despite the low parts cost. Oil leaking onto the serpentine belt poses a secondary failure and fire risk. The NHTSA TSB catalogue includes documentation of this failure mode on N20-family engines.

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

$400 to $1,300 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 2011–2019 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?

Inspect the oil filter housing area on the engine block for oil seepage, residue, or staining. Trace any oil tracks to confirm the housing is the source rather than the sump gasket. Check the serpentine belt for oil contamination. Ask for service history and note whether the repair has been done previously. Look here: Lower engine block, oil filter housing flange