The S63 engine is a twin turbo 4.4L V8 based on the same base design as the N63 engine. It was first released in 2010 for use in the BMW X5 M and X6 M. S63 engines then made their way into the M5 and M6 the following year. BMW's S63 makes an immense 547-617 horsepower. Many also believe BMW severely underrates the S63 power output. Regardless, it's one heck of a performance engine. However, no car or engine is perfect and that applies to the S63 M5, M6, and M8 models. In this article, we discuss some of the most common S63 engine problems along with overall reliability.
S63 Engine Generations
We'll write a separate in-depth article on this topic in the future, so we will keep it short for now. Anyways, BMW S63 engines have been through a handful of updates since their release in 2010. This is in part to continue progressing the M cars to make even more power. Some of the S63 updates over the years help the engine make extra power. Other updates are focused on emissions.
Let's move onto the real point we want to make, which ties into S63 reliability. As with any engine, there are always kinks to work out in the early days. N63 engines are a great example as the original N63's were a horror story and the newer N63TU3 engines are a drastic improvement. It might not be quite the same with the S63, but the engines has progressed over time. Newer S63TU engines are likely to be more reliable than the early S63's.
We will expand on this some where relevant throughout the post. We simply wanted to highlight that not all S63 engines are the same, and what we discuss in this post may be more or less relevant to certain year models.
4 Common S63 Engine Problems
A few common faults and failures on the BMW S63 X5 M, X6 M, M5, M6, and M8 include:
- VANOS solenoids
- Rod bearings
- Excess oil consumption
- Spark plugs & ignition coils
It's a good time to add a few notes prior to discussing the above S63 engine problems and failures in-depth. These are a few of the most common issues when problems do pop up. However, that doesn't mean a majority of S63 engines will actually run into these problems. There are also many other things that can go wrong with the S63 engine - this concept applies to all engines.
Anyways, keep in mind the S63 is a high performance engine in BMW M cars. The M5, M6, M8, and X M models are not cheap to own or maintain. Even without any major problems the S63 can be expensive. Brakes, tires, spark plugs, etc can add up quickly.
1) BMW S63 M5/M6 VANOS Solenoid Faults
VANOS is BMW's name for their variable valve timing (VVT) technology. VVT adjusts the timing of intake and exhaust valves by changing the position of the cams. It's not new technology and BMW has been using it for quite some time. However, VANOS adds quite a few extra parts to the engine and raises the possibility of additional problems. The S63 - along with many other BMW's - sometimes run into problems with the VANOS solenoids.
It may not be totally fair to call this a common S63 engine problem as it can be considered standard maintenance. The VANOS solenoids rely on oil flowing through them, which means they take some abuse. Over time, oil deposits form on the S63 Vanos solenoids and begin causing problems with proper operation. It's not a major issue, but the S63 does use 4 VANOS solenoids so the price of repairs can add up.
The solenoids are known to develop problems on the S63 around or beyond 100,000 miles. However, it's possible for them to fail sooner. Changing the oil on time and using high quality engine oils can help extend the Vanos solenoids life.
S63 VANOS Problems Symptoms
A few potential symptoms of Vanos solenoid issues on the BMW S63 engine include:
- Rough idle
- Hesitation / stuttering
- Engine fault codes
- Limp mode
- Power loss
When the Vanos solenoids aren't working properly the system cannot adjust valve timing accordingly. They typically fail over time due to build-up so symptoms often get worse with time. This will often cause rough idle, misfires, and hesitation. It may also throw a fault code suggesting a problem with the solenoid(s). More severe failure of the solenoids will cause the S63 M5/M6 to throw a check engine light, fault codes, and the engine may go into limp mode.
BMW S63 VANOS Solenoid Replacement
Replacing the VANOS solenoids is fairly simple from a labor perspective. Many with basic knowledge can DIY the solenoid replacement. However, the S63 uses 4 Vanos solenoids and those can run $150-200+ at the dealership. It's normally a good idea to replace all 4 at the same time, especially if you're north of 100,000 miles. As such, the parts can add up to quite a bit so we recommend finding a quality aftermarket option for solenoids.
2) S63 Rod Bearing Problems
Let's get this one out of the way early in this article. Chances are - rod bearing issues on the BMW S63 are blown way out of proportion. Part of this is likely due to some believing the M division can't figure out rod bearings. The S54, S65, and S85 engines all had their share of rod bearings problem. Though, even those were likely overblown.
That said, some S63 owners have run into premature rod bearing wear and failure. However, we'll never know how those engines were maintained. Rod bearing problems often start due to a lack of oiling or poor oil quality. That doesn't mean random bearing failures don't happen on S63 engines with a good maintenance history. It likely affects a very very small percentage of S63 engines, though.
We're simply discussing this since it's not hard to find some rod bearing horror stories around. Usually when an S63 rod bearing lets go it takes the entire motor out with it. As they wear down they eat into the crankshaft and can eventually cause the rod knock and piston slap. Basically, if it's not caught in time rod bearing failure may completely ruin an engine. It's not a common enough issue to scare us away from buying an S63 engine.
S63 Rod Bearing Failure Symptoms
Symptoms that indicate rod bearing problems include:
- Copper shavings in engine oil
- Rod knock
It's really hard to tell if the BMW S63 M5 or M6 rod bearings are failing. Copper shavings in the oil are typically the only real symptom until it's too late. Once the problem progresses you'll likely begin to hear rod knock. From there it's only a matter of time until the engine lets go. Again, this isn't a truly common failure on the S63. However, if you're concerned you might consider doing an oil analysis every couple oil changes. It's cheap to do and will tell you if anything looks abnormal.
BMW S63 Rod Bearing Replacement
If caught in time you can simply replace all 16 rod bearings. It's a labor intensive job, so it can easily run into the $2,000+ range to replace all of the S63 rod bearings. Some opt to replace them as preventative maintenance, but it's a lot of money to fix something that may be totally fine. Although, if rod bearings are left to fail they can chew up the crankshaft and cause a lot of additional damage.
3) BMW S63 Excess Oil Consumption
We'll speed things up moving through these next two common problems. The BMW S63 engine is known to consume oil at a pretty fast rate. Part of this may be due to the hot-vee design where the turbos lie within the V of the engine. All of that heat can lead to quicker oil loss for the S63. Often, the oil consumption is normal and isn't an actual issue in itself.
Of course, it's important to ensure you're topping up on oil as necessary. If oil loss is too excessive or continues getting worse then it's likely time to start looking into what may be causing the problems. The PCV system, oil leaks, faulty turbos, and many other issues can cause excess oil loss or consumption. None of these are truly common S63 M5 or M6 problems, but they can and do occur from time to time.
We'll leave it at that for now. Again, oil consumption in itself it's a huge concern but pay attention if it's getting worse or if you're burning more than 1L of oil every 700 miles or less.
4) S63 Spark Plugs & Ignition Coils
This is another topic we'll move through fairly quickly. Spark plugs and ignition coils aren't truly a problem on the BMW M5 & M6. Rather, it's standard maintenance that comes up a lot more often than some other engines. Turbo engines are already tough on the ignition system. Add in the fact the S63 is making 550+ horsepower and the ignition parts take a lot of abuse.
Expect to replace the spark plugs on the BMW S63 every 25,000 to 40,000 miles. If you're running a tune or bolt-on mods that life can be cut in half. Ignition coils on the S63 usually last about twice as long as spark plugs. However, once again, cut that life in half if you have a tune on the engine. These parts can wear down even faster if you're pushing the engine hard.
If you're running a tune you might also consider upgrading to 1-step colder spark plugs. The OEM plugs can cause issues at above stock power levels. This is especially true since a tune and basic bolt-ons can add an extra 100-150+whp.
BMW S63 Plugs & Coils Symptoms
Symptoms of faulty spark plugs or ignition coils on the BMW S63 include:
- Rough idle
- Stuttering / hesitation
- Power loss
The main symptom of worn out plugs or coils is misfiring. Those misfires may cause the S63 to idle rough, stutter while accelerating, and lose power. It will likely trigger a fault code indicating a cylinder misfire. Once you know which cylinder(s) is misfiring try swapping the ignition coil with a good cylinder. If the misfire follows then the S63 ignition coils are likely to blame. If the misfire does not follow it's likely the spark plugs.
S63 Plugs & Coils Replacement
Fortunately, replacing the S63 spark plugs is pretty quick and easy. Almost anyone can knock out the job in their driveway in less than an hour. OEM spark plugs come in around $100 for a set while 1-step colder NGK 97506 are about $160. Ignition coils cost around $250-400 depending on the specific year of the BMW S63 engine.
BMW S63 M5 & M6 Reliability
How reliable are the BMW S63 powered M5, M6, M8, X5M, and X6M? Overall, the S63 engine itself is fairly reliable. The engine doesn't suffer many serious common problems, but they can and do happen on rare occasions. However, it's a high performance engine used in high performance BMW M cars. Maintenance can add up quickly. This is especially true when you factor in the massive brakes, tires, etc. The BMW S63 might be reliable, but it's in no way a cheap engine to own.
Some engine problems are out of our control. However, stay on top of maintenance and fix issues in a timely manner when they pop up on the S63. Do this and owning an S63 will likely be a rewarding experience. Also plan for the standard BMW problems and maintenance north of 100,000 miles.
On a final note - the BMW S63 V8 is very receptive to tuning and mods. It can make a lot of power and dangerous amounts of torque in the low RPM range. That puts a lot of extra stress on the M5 and M6 engine and transmission. Stick with conservative tuning to help keep the engine safe.
S63 Common Problems Summary
BMW's S63 is an excellent performance engine from top to bottom. The twin turbo V8 makes an insane amount of power from the factory. It's also easy to mod and make an extra 100-200+ horsepower. There's no question it's one of the more impressive performance engines around. However, no engine is perfect and this applies to the BMW S63.
Look for issues with the ignition parts and VANOS solenoids. It's probably not fair to call these S63 problems since we consider them more maintenance items. Nonetheless, it's part of owning a high performance engine. Otherwise, some run into issues with rod bearings and excess oil consumption. Rod bearing issues on the S63 are likely blown out of proportion, though.
Overall, the BMW S63 is pretty reliable for what it is. As we stated a few times - it's not a cheap engine to own but it's a solid engine considering the amount of power and torque it puts to the ground. Maintain the S63 well, keep the engine stock, or stick with conservative tuning and you'll likely have a great experience owning the S63 M5/M6 engine.
What's your experience with the BMW S63?
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