Bmw N55 common problems

Are you a new Bmw owner and your car is equipped with the n55 engine? Here are some common problems that any N55 Bmw car has shown over the years with or without a software tune installed on the factory engine management system (ECU/PCM/ECM) .

In Case you own a BMW 135, 235, 335 ,435, 535, X1, X3, x4, X5, X6 or any other car with a manual (ZF S6-45) or automatic (ZF 6HP19 and ZF 8HP45) gearbox you will find here a list with several common problems which those engines have shown over the years.

Common N55 Engine Problems Brief List :

  • Boost and Charge pipe braking or detaching from throttle or inter-cooler.
  • Valve Cover Oil Leak
  • Water Pump Failure
  • Leaking Oil Filter Housing Gasket
  • VANOS Solenoid Failure
  • High Pressure Fuel Pump Failure (HPFP) – Mostly comes up on older models
  • Fueling system insufficiency (Can not hold more than +- 500hp) but you can compensate with wmi up to one level

The boost pipes issue :

A lot of owners and tuners have reported problems with both of those pipes especially after a tune on the n55 platform. The pipe on the left side (charge pipe) is attached to the throttle with a small metal safety clamp which can not hold higher boost pressures(usually brakes up after 1.1 bar) and in some cases not even stock boost when the car gets too warm inside a race track or after hard use on the street.

Exactly the same thing can happen to the boost pipe which is connected directly to the intercooler and in that case you need to replace everything plus the o-ring seals inside it. We would suggest those upgrades to be done prior ecu tuning or directly after the car is purchased. Aluminum connection pipes should be used which are sold by a lot of companies as an upgrade for the N55 engine.

N55 Valve Cover and Gasket Leak Symptoms:

  • Low engine oil light
  • Burning oil smells, or smoke coming from valve cover area
  • Oil on spark plug threads

The same exact valve cover leaks were also appearing on high mileage older N54 engines. In addition directly on the valve cover is the Positive Crankcase Ventilation Valve (PCV valve). Rough idle is one of the symptoms that will be caused by a broken pcv valve.

A PCV valve is basically a diaphragm that with the help of engine vacuum pulls out blow-by gases that are generated inside the crankcase. Usually PCV fails due to high mileage and/or high engine temperature and pressure.Consider replacing the complete valve cover and gasket since it is easier and will solve both issues at once.


N55 Water Pump Failure

  • Engine overheating  –
  • Cooling Fan running full speed(constantly)
  • Coolant boiling
  • CEL DTC : 2E81, 2E82, 2E83, 2E84, 2E85, 377A

The common water pump problems are a usually found on most bmw engines and not only.Water pumps are re-circulating coolant to cool down your engine temperature. Bmw is using electric water pumps on n54 and n55 engines and those pumps have a short lifespan(+- 50.000km). Once you decide to replace the water pump consider replacing the coolant thermostat as this is also a weak link on those engines and it would be easier to change both at once.

BMW water pumps can let you down without any prior notification. A good way to diagnose the pump is to check the flow using some special tools and the factory inpa/icom diagnostic interface. If the failure is electrical you might also get a dtc registered to your engine management system.

More details coming soon for the rest of the problems.

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