First time we’ve see this on this engine, the BMW N52, though on the earlier M54 series of engine, crankcase breather updates are very common. In this case the car presented with very loud whistling noise under the hood, problem is that it would come and go when the engine was turned off, on restart the noise would vanish. Using our special BMW diagnostic tool, we confirmed a severely clogged engine breather box, on this engine located in the camshaft cover, another key diagnostic indicator was the oil fill cap was stuck down by excessive vacuum, negative pressure. Not an easy job as this engine has “Valvetronic”, but one that needed to be handled. In the past, we’ve found these breather failures are much more common in colder weather.

In the photos below, you’ll note the large camshaft cover assembly that must be replaced for clogging. Such clogging has become an issue with the later breather systems, we’ve seen it many times on Audi, not so common on BMW. The build up of this material prevents the crankcase ventilation system from functioning correctly, and will lead to an increase in crankcase negative pressure, external oil leakage. In severe cases it can build up enough negative pressure to damage engine seals, including the rear main seal. Any problem with multiple engine oil leaks must first be dealt with by inspecting and servicing the crankcase ventilation system.If you car has the symptoms noted above, you might want to give us a call, BEFORE the failure occurs. The update cost is minimal compared to the damage which can result. Our goal at Atlantic Motorcar, to provide the lowest possible cost by preventing problems first, rather than just repairing them.

Here is how you can take some simple precautionary steps:

  1. If you have no choice but to make short trips, try and take your vehicle on the freeway at least once per week, as this will help burn off condensation.
  2. Avoid excessive idling or allowing the car to warm up.
  3. Keep Your vehicle garaged at night, if possible, when the temps are very low.
  4. Change your engine oil every 5,000-7,000 miles, always using full synthetic.
    We strongly advise not to follow BMW’s 12,000-15,000 mile oil change intervals, we have an expression here, “Oil is cheaper than metal”, keep your engine oil clean, and change on a frequent basis and your BMW will serve you well.