The BMW N63 – From Hot Vee To Hot Garbage


Before getting started I wanted to say I feel bad about calling the BMW N63 ‘hot garbage’.  The N63 Twin Turbo 4.4l V8 is a wonder of modern technology, achieving things that no other engine maker was willing to attempt.  The manufacturing processes that went into crafting it are exquisite.  That says a lot for BMW, as they refuse to allow technical innovation to stagnate.  One of the cars that this was installed in was the BMW 750li, a vehicle that approaches 5,000lbs with driver, makes almost 450hp, and still manages to get around 25mpg on the highway.  That’s V12 performance out of a V8, and impressive no matter how you cut it.  But alas, when you shoot for the stars you are bound to get a few failures to launch.

Breaking new ground with the BMW N63

When it came out in 2008, the future looked bright.  Utilizing some interesting concepts, such as the hot-vee (exhaust exits into the turbos on top of the engine, in the valley, rather than out the bottom), BMW was taking a lot of risks doing it this way.  This design, as well as the now-common high pressure direct injection system, led to some complexities that in hindsight probably should have better been left on the table.  The engine bay packaging is great though, nobody can argue that.

One interesting over-complexity is the use of air-to-water intercoolers, rather than the standard style air-to-air exchanger.  This is meant to save space and dramatically shorten the intercooler piping.  However, because of how much heat is being generated, the air-to-water intercoolers utilize a separate coolant pump and reservoir, and THAT has its own radiator in the front of the engine.  What this does effectively is kill two birds with one Tomahawk cruise missile, fired from orbit.

The N63B44O0 engine was the first N63 to ship, and went into 5-series, 6-Series, 7-Series, X5, and X6 model that have names ending with a ’50’ between 2008 and 2012.  With such fresh technology, the odds of it reaching the beach was questionable.  Shortly after launch, BMW owners started complaining about problems ranging from abnormal oil consumption and rough idle, all the way up to complete failures.  Enough N63B44O0 engines were coming into dealers with severe engine problems that BMW launched a preemptive fix campaign to help alleviate the risk of having to replace entire BMW N63 engines under warranty.

The N63 Customer Care Package, Service Bulletin B001314

In 2012, the BMW N63 received its first major technical update, known the N63B44O1.  Also referred to as the N63TU ‘Technical Update’, it used several components off the venerable N55 turbo engine. These include the fuel injectors (which utilized a different style design) and Valvetronic III variable lift intake cam system, which was omitted at the original launch.  However, this was not enough to fix the ailing powerplant, and the N63 continues to be plagued by issues baked in from the original design.

In December of 2014, BMW launched a campaign called the Customer Care Package, which is widely covered across the internet.  Sometimes requiring in excess of 40 hours of labor worth of work, the Customer Care Package was meant to cut off the naysayers at the pass and fix the problems before they happened, without using the dreaded R word (recall, oops I said it).  It went well, with many people dropping off practically new cars and having substantial preemptive work done.  Good on BMW for doing this, although many agree they pretty much had to.  Here are some of the things that this covered:

Even with a huge amount of heat shielding, the electrical system still struggles to power the cooling system after engine shut-off

Battery issues

Predating the N63, the BMW Efficient Dynamic system utilized regenerative braking to help the alternator to charge the battery.  Because the system relied on a driving style with a lot of off-throttle coasting, in certain driving situations the battery would not be adequately charged.  BMW started using AGM batteries to help with the situations of deep discharge, which was effective until the N63 showed up. With the extraordinary amount of heat in such a small space, the cooling system had to work overtime to keep temps down after the car shut off.  That meant extended running of fans and electric water pumps well after the engine shut off.  The size of the battery was increased, but in some cases this was still not enough.  The solution was to just continuously replace batteries, sometimes as often as every oil change.

Oil Consumption

The owner of this BMW has a great article describing his experience

The BMW N63 is a thirsty motor, and this became apparent early on.  BMW (unofficially, I can’t find the official statement to confirm this) suggests this is due to an improper break in and going too easy on the motor while brand new.  Because not everyone drives their luxury land-yacht like they are in ‘The Fast and Furious: Deutsch Rennwagen fahren mit hoher Geschwindigkeit‘, the oil change interval was moved from the insane 15k miles, to 10k.  An extra liter was added to the capacity of the sump to make all the way to 10k without a top-up.

Additionally, because of how hot the top of the engine is, the plastic PCV system gets an extreme workout in the heat cycling category.  This causes hoses to crack and break, and seals to shrink, causing oil leaks all over the place.  Typically these manifest themselves as a faint waft of oil smoke coming out from under the hood, very luxurious.

Speaking of Luxurious, the valve stem seals are another non-metal component on the top of the engine that are subjected to huge doses of turbo heat.  Eventually they will start to leak, causing your high end BMW to smoke like a Dodge Monaco after a few too many years in the front yard.  A friend of mine runs a shop called Swedish Performance outside Raleigh, NC, and sees these come in often.  He recently did the valve seals on an N63 equipped X5, and sent a few photos of what the job was like.  Looks like a good time.BMW N63 Valve Stem Seal Replacement

 

Fuel Injection

High Pressure Fuel Injector A2C9521190280Even though the injectors were changed between the first generation and the technical update, the high pressure fuel injector units are still, and always will be, a constant problem for owners with the N63 engine.  These were checked and replaced under the Customer Care Package with an updated style of injector.  This is why many N63 owners will notice that the dealer may have replaced all of your fuel injectors at once.  The updated injectors can’t be intermixed with the outgoing style, and really, why would you want to risk it anyway?  I have even read reports of broken injectors flooding cylinders with enough raw fuel to trigger a chain reaction, ultimately ending in hydro locking and complete engine failure.

Direct injection engines are susceptible to numerous issues, and the N63 is no exception.  Because fuel is being blasted at high pressure directly into the combustion chamber, rather than spraying at a low pressure past the open intake valves (like standard port injection cars), there’s nothing to clean the backs of the valves off.  Where port injection engines use gasoline to keep the valves free of PCV oil and sludgy carbon crud from the combustion chamber, the intake valves on direct injection cars get caked on with black buildup called coking.  This will make the engine run terrible due to constricted, rough air passages.  BMW’s official intake valve cleaning requires removal of the intake manifolds (on the bottom of the engine for the N63), and then a thorough media blasting with broken up walnut shells.  Then the shells are vacuumed out of the chambers.  Yes, walnut blasting is a thing, and will keep any direct injection car running right.

Timing System

The N63’s timing system is not immune to issues either.  Stretched and broken timing chains have claimed numerous engines before they could get the Customer Care Package inspection and replacement.  Here’s a particularly spooky thread outlining the experience of a 750li driver that had a massive timing failure just 4000 miles after the CCP was performed, ultimately totalling around $15k in engine out service work.  The owner states it was the result of a broken chain guide, rather than the commonly broken or stretched chain itself.  If you plan on trying to do the timing on one of these yourself, be aware we have several of the required special tools to rent.

The Rest

As part of the BMW N63 Customer Care Package, the Mass Air Flow sensor (which is the high precision hot film type MAF) as well as the vacuum pump was commonly replaced.  I am not sure if these parts are updated versions currently, like the injectors, but their failure is most certainly linked to the heat of being directly adjacent to the exhaust manifolds and turbochargers. The vacuum pump is also on the list of likely replacement under the CCP.  Granted, this is not all of the strife faced by owners of these latest generation of cars, which also feature problems with the drivetrain, active suspension, and other numerous systems.

All in all, the internet has no shortage of people flooding forums looking for answers as to why their BMW is running poorly, and it goes without saying that’s a horrible feeling.  A cursory Google search reveals multiple class action lawsuits, but to be fair to BMW they are fixing these cars for the most part.

We’ve been noticing a steady uptick in N63 parts and special tool rentals, specifically the fuel injectors, PCV kits, and oil and coolant seals.  If you are looking at buying a car with the N63 engine, be warned of these potentially critical issues associated with them.

 

 

 

 

 

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6 thoughts on “The BMW N63 – From Hot Vee To Hot Garbage
  1. Richard Tabanico

    I have a couple of BMW’s to which I have replaced one engine do to flooding. After reading your discussion on the N63 I’m wondering what feed back have you received on the N54 or N55 engines. I have planed to replace and rebuild a used N54 turbo into my 528i for the upgrade. Any information available to the dependability would be appreciated.
    Thanks

    • Adam Goral

      While not a specific point of interest like the N63 is in terms of strange issues, the N54 had similar teething issues being the first commercially produced turbocharged engine BMW produced. One particularly interesting failure we’ve seen on both the N54 and N55 is that oil leaks onto the belts from the oil filter housing. That causes the belt to weaken and slip off, getting jammed under the main crank pulley and thusly sucked into the engine past the main seal and blowing everything up. Many BMW’s will suffer from these same oil filter housing leaks, so they definitely need to be looked out for.

      Another thing to look out for is also applicable to all BMW’s with direct fuel injection. Although the N54 specifically had issues related to the high pressure fuel pump, all DI cars will accumulate carbon buildup on the valves and require a walnut blasting every so often which is a big job. Many small issues with the N54 were ironed out for the N55 (which is a substantially different engine on many levels). That’s not to say both of these engines won’t require occasional and substantial maintenance in their life time, for most people the joy of having an engine as capable as these is worth the expense.

  2. PERRY

    How’s the reliability regarding to the N63TU engine? I haven’t heard much of the issues except adding 1qt oil between oil change. What’s your experience?

    Thanks
    Perry

    • Adam Goral

      Hi Perry, the N63TU is the ‘Technical Update’ and has several design changes that were borrowed from other successfully reliable engine models. However, strictly due to the configuration of the engine, the N63 will always have the issues above, except for maybe the fuel injectors which were updated. Even then, due to the immense heat, all these components are put under significantly more stress than other engines.

  3. Jerry Hancock

    I have an N63 in my X6 iDrive 5.0 with twin turbo. Nothing but problems from day 1. Started with three sets of fuel injectors and I think by the time I was done, I had totaled about 12K in repairs. All these problems started under warranty.
    At 36K miles, the engine went from consuming maybe 1qt of oil per 1,000 miles to 2qt or more. BMW tracked the oil consumption up to 56K miles telling me this was normal oil consumption. At 56K they said, no, let’s change out some breather hoses. This did nothing. So why would they change the breather hoses to fix the problem if it was normal? Ultimately it started smoking and I parked the car at 95k miles. My wife drove it even though it smoked. I talked to BMW customer sat (dis-sat) many, many times without help. Most recently, the dealer quoted 20K to replace the seals and BMW said they would cover 40%. Absolutely ridiculous! So the car remains parked. I paid 70k USD for the POS. They said I got 95k miles from the car. I say the miles mean nothing!! it’s the fact that the problem started under warranty, they knew it had an issue and they didn’t fix it!

    • Adam Goral

      That’s a horror story above and beyond what I am used to reading, sorry this happened. If I were you I would call a lawyer that specializes in cases like this and see what they have to say since the problem stemmed while the car was under warranty, maybe you can recoup some of this to keep it from being a total loss. Another option is to take it to an independent shop (like Swedish Performance outside Raleigh, NC) as some of these places are getting really good at doing this work, as practice makes perfect afterall. At that point you can dump a few grand into it, get it running back to normal, and sell it.

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