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BMW 4.4-liter N63 Engine Experiencing Frequent Reliability Problems

This weekend, my car needed some maintenance, to get ready for the winter that is rapidly approaching. Therefore, as I was waiting for my car to get ready, I started talking to the mechanic about a variety of things and amongst them was the reliability of new engines compared to old ones.
BMW 750Li smoking up 4 photos
Photo: Bimmerfest.com
BMW 750LiBMW N63 cracked blockBMW N63 faulty block
As it turns out, even the mechanics working for BMW agree that ‘they don’t make them like they used to anymore’. It would be downright impossible as well, considering what is required from a powerhouse these days.

No longer are naturally aspirated units the norm but instead forced induction took over. That was bound to result in more problems as well. As it turns out, if you add more electronics and sensors to an engine, it becomes more of a liability. Who would’ve thought?!?

I’m being ironic, of course, but what shocked me was that today, some BMW engines barely make it past the 62,000 mile (100,000 km) mark. As my mechanic was talking, I was getting more and more intrigued.

The N63B44O0 4.4-liter twin-turbo V8 is a bomb on wheels

What he was saying wasn’t making any sense. He claimed that the original N63 engine that goes by the codename N63B44O0 is a downright bomb on wheels. According to him, he changed at least a dozen of them because of faulty injectors or a faulty high pressure fuel pump.

It seems like the injectors would shoot too much petrol inside the cylinder which would in turn cause some shrapnel to come off that would eventually get stuck in all sorts of places and cause the piston to crack the case. Basically, you’d be in for a surprise when a rod or even a piston would shoot through the engine block.

That would, in certain cases, lead to a shot oil sump and other various damages. Being a more reluctant person, I though he was talking gibberish at first but then I went online and started digging.

The internet confirmed his story

As it turns out, plenty of people have had this problem so far. The internet is filled with stories such as this one, where owners have had their complete engines swapped under warranty.

Sure, it’s all nice and good when this happens under warranty but what about those that aren’t covered? Well, you’d better be really careful if you’re planning on getting a car that uses this engine.

To be more precise, we’re talking about the 2008-2014 BMW E71 X6 xDrive50i, the 2009 - 2012 BMW F01/F02 750i or 720 Li, the 2010-2012 550i models (sedan, wagon or GT), the 2011-2012 E70 X5 xDrive50i and some early versions (built in 2012) of the F12/F13 650i models.

Those units are the ones built before the facelift came out. In 2012, BMW released the same engine with a technical update, called N63B44O1. This one also makes more power, being rated at 450 HP and 650 Nm (480 lb-ft) of torque instead of 408 HP and 600 Nm (440 lb-ft) of torque as the faulty one.

How can you tell if your car has this issue?

Unfortunately, you can’t really tell if your car has this problem until it’s too late. Usually, the fault starts to manifest itself with a warning light popping up in your dash saying that you car’s engine is now running with reduced power.

Other indicators include taking a long time to crank the engine, blue smoke (a lot of it) and misfiring on the cylinders. If that happens, you should turn off the engine and have your car towed to the dealership to get it fixed. Running it for even 5 extra minutes could compromise it completely.
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