BMW N54 Engine, Common Problems, Reliability. The Ultimate ‘What to Look Out For’ Guide
The N54 is BMWs famous twin turbocharged 6 cylinder petrol engine, used most commonly in the 335i, 535i and 135i. This monster is capable of pushing 335hp and known for its impressive tuning capabilities.
Now that all sounds great, but let’s go over some common problems that every N54 owner should be aware of.
Carbon build up and walnut blasting
The N54 is direct injection and so sprays fuel directly into the combustion chamber, increasing fuel efficiency but leading to a build up of carbon on the intake valves. This carbon build up can hinder airflow. This problem is often diagnosed when the customer notices a rough idle, gradually worse fuel economy and occasionally a check engine light can occur.
Luckily there is a solution called walnut blasting to remove this carbon build up and get your car running smoothly again.
Engine failure by belt stuck in oil pickup leading to oil stavation
Yes you read that right! There is a common oil leak on the N54 which commonly causes the belt to slip and get pulled into the engine behind the front main crank seal. This rubber belt then of course blocks the oil pickup causing oil starvation and major engine failure.
It is essential to keep on top of all engine leaks from the N54, and we know there are many! These engine are notorious for springing one oil leak after another. We recommend contact a specialist as soon as you notice oil leaks, preventative maintenance is always worthwhile.
VVT have created a shield that will stop the belt from getting behind that front main seal, which considering how frequently oil leaks occur and the potential consequences faced is something we think every n54 owner should consider.
Turbo problems and wastegate rattle
One of the first things you may notice is a rattling sound from your turbos. This annoying noise from the wastegate is an indicator that your wastegate flapper bushing is worn out. Luckily there are kits available to fix this. The job is quite extensive and requires the removal of the turbos but it will fix this rattling once and for all.
Turbo failure. The n54 turbos are frequently known for their failure, there is a wide range of aftermarket upgraded ones available that should remove all future turbo problems from your n54’s life.
Cooling Problems: Water Pump and Electric Thermostat
Incase all of that laundry list of problems wasn’t enough. The water pump is almost considered a consumable part for these engines, often failing as early as 50k miles. You may notice your water pump making unusual running sounds or running at peculiar times that it didn’t used to. Code 378F is an indication of a water pump problem. This is something to get replaced earlier rather than later, nothing about the cooling system on these hot running cars is to be messed with.
Fueling: High Pressure Fuel Pump Failure (HPFP)
Many n54 owners find themselves with fuel pump problems. A common symptom of your fuel pump struggling is a longer crank than usual when starting the car. Unfortunately for a lot of owners the first symptom is when your car suddenly breaks down, which is far from ideal.
Here at Element Performance, we are pleased to offer a range of N54 services including those mentioned above. You can directly to our technicians about your car and specific requirements.