BMW 3 Series: N55 3.0T oil filter housing gasket leak onto the drive belt (335i)
N55 3.0T oil filter housing gasket leak onto the drive belt (335i) is a common fluid leaks fault on the BMW 3 Series on the 2010–2016 cars, and we rate it major. Putting it right costs ≈A$460 to ≈A$1,380 at independent workshop rates, shown as an approximate guide in Australian dollars. 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 92 documented faults on the BMW 3 Series.
- Vehicle
- BMW 3 Series
- Engine
- N55
- Years
- 2010–2016
- Fuel
- petrol
- System
- Fluid Leaks
What you are looking at
No photograph available
What goes wrong
The N55 3.0 litre turbo six in the E90/E92/E93 335i from 2010 and the F30 335i has an oil filter housing bolted to the side of the block, sealed by rubber gaskets that harden and shrink with heat and age. An oil filter housing gasket leak is a known issue on this engine, with oil running down the side of the block onto the drive belt, tensioner and exhaust. Left alone, oil soaked belts can slip, shred and be dragged behind the crank pulley into the front crank seal, which can cause serious engine damage. Access to the housing is tight, so labour (about four hours) is the main cost of the repair.
What you would notice
- Burning oil smell from the engine bay after a drive
- Oil wetness down the intake side of the block behind the filter housing
- Oil on the drive belt, tensioner or under tray
- Squealing or a frayed drive belt
- Slowly dropping oil level between services
How to check it
Where to look. Engine bay, intake side of the engine block below the intake manifold, oil filter housing next to the drive belt
Look down the intake side of the engine below the oil filter housing for wet oil or caked grime, and check the under tray for fresh oil.
Look at the drive belt and tensioner for oil and fraying, and listen for belt squeal at idle.
Ask whether the oil filter housing gasket or housing has been replaced and ask for the invoice.
If a workshop inspection is possible: have the car put on a hoist to trace the leak source and check the belt and crank pulley area.
What it costs to put right
≈A$460 to ≈A$1,380 at independent workshop rates, shown as an approximate guide in Australian dollars. That is for this job on its own, not for the car.
Ask the seller
- “Has the oil filter housing gasket or housing been replaced, and when?”
- “Has the drive belt ever been replaced because of oil contamination?”
- “Does the engine use or leak oil between services?”
Now check the BMW 3 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 still has money owing on it, has been written off or reported stolen, what kms it showed in past sale ads, whether it has had accident repair claims and what it is worth today. That comes from the official records for that plate. Enter the plate and its state for the A$17.90 Vehicle Check, or the full history from A$24.99.
Where this comes from
BMW 3 Series buyer questions
Is n55 3.0t oil filter housing gasket leak onto the drive belt (335i) serious on a BMW 3 Series?
We rate it major and common on the BMW 3 Series. The N55 3.0 litre turbo six in the E90/E92/E93 335i from 2010 and the F30 335i has an oil filter housing bolted to the side of the block, sealed by rubber gaskets that harden and shrink with heat and age. An oil filter housing gasket leak is a known issue on this engine, with oil running down the side of the block onto the drive belt, tensioner and exhaust. Left alone, oil soaked belts can slip, shred and be dragged behind the crank pulley into the front crank seal, which can cause serious engine damage. Access to the housing is tight, so labour (about four hours) is the main cost of the repair.
How much does it cost to fix on a BMW 3 Series?
≈A$460 to ≈A$1,380 at independent workshop rates, shown as an approximate guide in Australian dollars. 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 3 Series years are affected?
Our research records this fault on the 2010–2016 BMW 3 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?
Look down the intake side of the engine below the oil filter housing for wet oil or caked grime, and check the under tray for fresh oil. Look at the drive belt and tensioner for oil and fraying, and listen for belt squeal at idle. Ask whether the oil filter housing gasket or housing has been replaced and ask for the invoice. If a workshop inspection is possible: have the car put on a hoist to trace the leak source and check the belt and crank pulley area. Look here: Engine bay, intake side of the engine block below the intake manifold, oil filter housing next to the drive belt