BMW 1 Series: B58 oil filter housing gasket leak, oil and coolant (M140i)
B58 oil filter housing gasket leak, oil and coolant (M140i) is a common fluid leaks fault on the BMW 1 Series on the 2016–2019 cars, and we rate it major. Putting it right costs $700 to $2,200 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
- B58
- Years
- 2016–2019
- Fuel
- petrol
- System
- Fluid Leaks
What you are looking at
No photograph available
What goes wrong
The first-generation B58 3.0 turbo six in the F20/F21 M140i has a plastic oil filter housing that also carries the oil-to-coolant heat exchanger. With heat cycling the gaskets between the housing, the block and the cooler flatten, and the plastic can warp or crack, so the engine weeps oil, coolant or both. Oil runs down the intake side of the engine and a coolant leak into the oil can mix the two fluids, which is the expensive outcome. BMW faces a US class action over this housing on B46, B48 and B58 engines in 2014 to 2021 1, 2, 3 and 4 Series cars; there is no recall or extended warranty in NZ or AU.
What you would notice
- Burning oil smell after a drive
- Oil wetness on the left (intake) side of the engine below the filter housing
- Coolant level slowly dropping with no puddle
- Milky or oily film in the coolant expansion tank
How to check it
Where to look. Left (intake) side of the engine at the front, where the oil filter canister screws in from the top
With the bonnet up and the engine cold, use a phone torch to look down the intake side of the engine around the oil filter housing and below it for wet oil, crusty white or pink coolant residue, or signs of fresh cleaning. Check the coolant expansion tank level and look for an oily film on the coolant. Look under the oil filler cap for a milky, mayonnaise-like layer. After the test drive, sniff for a hot oil smell at the bonnet shut line. Ask whether the oil filter housing or its gaskets have been replaced and ask for the invoice. If a workshop inspection is possible: have the cooling system pressure-tested and the housing area checked from underneath on a hoist for oil and coolant tracking.
What it costs to put right
$700 to $2,200 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “Has the oil filter housing or its gaskets ever been replaced?”
- “Do you have to top up coolant between services?”
- “Has the car ever shown a low coolant warning?”
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.
Where this comes from
- BMW oil filter housing class action naming B46, B48 and B58 engines in 2014-2021 1/2/3/4 Series (Autoblog; CarComplaints)
- Turner Motorsport / ECS Tuning Genuine BMW oil filter housing replacement kit 11428583895KT for F22/F23/F3X B58
- BMWTuning.co "The 5 most common BMW B58 engine problems" (coolant loss and oil filter housing, M140i/M240i/340i/440i)
BMW 1 Series buyer questions
Is b58 oil filter housing gasket leak, oil and coolant (m140i) serious on a BMW 1 Series?
We rate it major and common on the BMW 1 Series. The first-generation B58 3.0 turbo six in the F20/F21 M140i has a plastic oil filter housing that also carries the oil-to-coolant heat exchanger. With heat cycling the gaskets between the housing, the block and the cooler flatten, and the plastic can warp or crack, so the engine weeps oil, coolant or both. Oil runs down the intake side of the engine and a coolant leak into the oil can mix the two fluids, which is the expensive outcome. BMW faces a US class action over this housing on B46, B48 and B58 engines in 2014 to 2021 1, 2, 3 and 4 Series cars; there is no recall or extended warranty in NZ or AU.
How much does it cost to fix on a BMW 1 Series?
$700 to $2,200 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 2016–2019 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?
With the bonnet up and the engine cold, use a phone torch to look down the intake side of the engine around the oil filter housing and below it for wet oil, crusty white or pink coolant residue, or signs of fresh cleaning. Check the coolant expansion tank level and look for an oily film on the coolant. Look under the oil filler cap for a milky, mayonnaise-like layer. After the test drive, sniff for a hot oil smell at the bonnet shut line. Ask whether the oil filter housing or its gaskets have been replaced and ask for the invoice. If a workshop inspection is possible: have the cooling system pressure-tested and the housing area checked from underneath on a hoist for oil and coolant tracking. Look here: Left (intake) side of the engine at the front, where the oil filter canister screws in from the top