The BMW N20 is a 4-cylinder, turbocharged engine produced from 2011-2017, and was BMW’s replacement for the naturally aspirated 3.0L 6-cylinder N52/N53 engines. As the outgoing N52 and N53 were reliable engines, the BMW N20 had big shoes to fill, especially given its turbocharged design. Turbo engines are more complex and require several additional components, which means there are more things to potentially go wrong. However, thus far, the N20 has proven to be a reliable engine without a significant number of common problems.
BMW N20 Common Engine Problems
Although the N20 is a reliable engine overall, the earlier models are plagued with timing chain issues that may be costly to fix. Simply because some engine problems are common does not mean they will indefinitely experience issues on every engine. Additionally, N20 engines are susceptible to many other issues that we will not classify as common issues, as they may only pop up on a small percentage of engines. So, what are the most common issues on the BMW N20?
1. Timing Chain
The timing chain appears to be the number one fault on the N20, however, this issue is mostly prevalent on engines and vehicles produced prior to 2015. In January 2015, BMW redesigned the timing chain components, which seems to have significantly reduced the chance of failure. For certain vehicles produced prior to 2015, BMW offered an extended warranty for 7 years/70,000 miles on the timing chain and components.
In the unfortunate scenario where your N20 was not offered the extended warranty or is outside the age or mileage of the warranty, then the timing chain replacement can be a significant cost. In the worst scenario, a complete timing chain failure could potentially lead to engine failure. Generally, independent repair shops charge $1500+ for parts and repair, while the cost at a BMW dealership may be nearly double. This is a relatively tough DIY job, however, the timing chain and components cost roughly $500.
Symptoms of BMW N20 Timing Chain Failure
- Loud Whining from Engine
- Typically, very loud and noticeable
- Significant Scoring on Chain
- Too Much Slack/Play
The most common symptom is a loud, noticeable whining sound from the N20 engine. Engines may make audible, but quiet whining noises under light revs/acceleration, however, this is unlikely to indicate a timing chain issue. An overwhelmingly loud whine may suggest the timing chain is beginning to fail. Additionally, significant scoring or scratching on the timing chain may point to an underlying issue. Although, some scoring is normal due to age and wear and tear. The same may be said for slack or play in the timing chain; small amounts are normal, while significant slack or movement in the chain may suggest an issue. You may inspect the BMW N20 timing chain by peering through the oil cap.
DIY Difficulty – Intermediate to Advanced
Cost to Repair N20 Timing Chain & Components - ~$200 DIY, $1000+ indy shop
Mileage – May fail earlier, but usually after 50,000 miles
Other BMW N20 Engine Problems
The timing chain seems to be the most significant issue on the N20, and primarily only affects vehicles produced before 2015. Apart from the timing chain it is tough to come up with any issues that are truly common to the BMW N20. Of course, as engines age and accumulate more mileage there may be some common issues that come up due to typical wear and tear. Here we will review a few issues that may be the most common “wear and tear” problems.
1. N20 Valve Cover and Valve Cover Gasket
As with its larger 6-cylinder turbocharged BMW siblings, the BMW N20 uses a plastic composite valve cover (VC) and a rubber valve cover gasket (VCG). With increased mileage and age the valve cover and valve cover gaskets may become brittle and begin cracking. This is mostly due to the nature of heat cycles where the engine and components heat up and cool down constantly as you drive the car and let it rest for long periods. Once the valve cover and/or gasket develop cracks they will begin leaking oil. Typically, this begins as a minor leak and may not be noticeable until it expands, or additional cracks develop.
Symptoms of Valve Cover and/or Gasket Leaks
- Visible oil leak
- Burning oil smell
Due to the tilt of the engine, this is usually noticeable just below the engine cover on the left side of the engine, when viewing the car head on. Smoke coming from the engine bay will likely become prevalent as the leaking oil may drip onto the extremely hot exhaust or turbocharger. For the same reason, you may notice a burning oil smell inside the cabin with the A/C or heat turned on, without using the air recirculation.
It is unlikely a minor leak will cause any significant issues on the N20, however, over time the leaking oil may cause premature wear on parts such as engine or transmission mounts. Fire may also be a concern as the oil typically drips onto very hot components. The N20 VC and VCG are relatively inexpensive parts at about $300 for the valve cover, gasket, ball pin, shaft seal, 4 damping elements, and 20 bolts. Repairs done at a shop may add up as it is a labor-intensive replacement.
DIY Difficulty - Intermediate
BMW N20 Valve Cover (for BMW N20B20A) - Full kit including valve cover, gaskets, and bolts
BMW N26 Valve Cover (for BMW N26B20A) - Full kit including valve cover, gaskets, and bolts
**We recommend replacing the entire valve cover, especially over 100,000 miles.
N20/N26 Valve Cover Gasket (gasket only)
Cost to Repair - ~$300 DIY, $500+ independent repair shop
Mileage – 6+ years, and 60,000+ miles. May be sooner, or may hold up well past 100,000 miles
2. Oil Filter Housing Gasket
We won’t spend much time discussing the N20 oil filter housing gasket (OFHG) issues. As you may have guessed, it is very similar to the valve cover and gasket. It is a rubber component that is subject to similar wear and tear with age, mileage, and heat cycles. The gasket may begin to crack over time, which will lead to the development of an oil leak. It is also possible the oil filter housing itself develops a crack and subsequent leak, but this is less likely than the gasket alone.
Symptoms of a leaking OFHG are like the VC/VCG, however, the oil leak will be observable in the area of the oil filter housing. The gasket is only roughly $10, while the oil filter housing runs over $300, including the cap, oil filter, and gaskets. The OFH/OFHG also are somewhat labor intensive, so costs may add up at independent repair shops or the BMW dealership.
DIY Difficulty – Intermediate
BMW N20/N26 Oil Filter Housing - Includes housing, filter, cap, and gasket
BMW N20/N26 Oil Filter Housing Gasket - Gasket only
Cost to repair - $10, or $300 to DIY, $500+ at independent repair shops
Mileage – 6+ years and 60,000+ miles. May be sooner, or may hold up past 100,000 miles
Final N20 Wear and Tear Items to Consider
Obviously, as cars age there is no way to tell what will end up failing in the long-run as wear and tear takes a toll on almost all components. However, a few other issues that are most likely include:
- Coolant Hoses
- Vacuum lines
- Vanos Solenoids
All in all, the BMW N20 is a reliable engine and does not have many common issues that warrant concern until higher mileage. For the DIY crowd, a lot of the repair jobs mentioned are not overly expensive as the cost of parts is not too high. For the shop goers, some of the repairs are lengthy and labor intensive so the costs may add up.
BMW N20 General Maintenance
As with any engine, the BMW N20 is also subject to standard maintenance items such as fluid changes and ignition components. We will not discuss vehicle maintenance such as tires and brakes, but rather focus on the maintenance recommendations for the N20 engine specifically. Below is a list, in no specific order, of general maintenance items to expect on your BMW.
1. N20 Spark Plugs & Ignition Coils
These components play an important role in gasoline engines as they are directly responsible for igniting the air/fuel mixture in the cylinder, thereby generating power. Ignition coils transform the car battery voltage into the thousands of watts required to send a charge to the spark plugs. The plugs then create the spark that is required to ignite the air and fuel in the cylinder. Each time a cylinder fires, the associated ignition coil and spark plug must do their jobs completely to generate a large enough spark to generate a full burn, otherwise the engine will lose power. Eventually, due to wear and tear caused by age and mileage, the plugs and coils will no longer work to the best of their ability.
It is recommended the spark plugs are changed every 50,000-60,000 miles on stock N20 engines, while modified or tuned N20’s may require replacement as often as 20,000 to 25,000 miles. On the other hand, ignition coils should be changed every 60,000-75,000 miles on stock engines and tuned engines may burn through them as soon as 30,000 miles.
Recommended Maintenance Interval
Stock Engine: Spark plugs every 50,000-60,000 miles; Ignition coils every 60,000-75,000 miles
Modified/Tuned Engine: Plugs every 20,000-25,000 miles; Coils every 25,000-35,000 miles
Spark Plugs: $65-89 DIY, $120+ at an independent repair shop
Ignition Coils: $159 DIY, $250+ at a repair shop
2. Engine Oil
Although it is obvious engine oil must be changed as a part of standard maintenance, it is relatively unclear how often. Browsing the forums, a lot of people will suggest 5-7k (thousand) mile oil changes, while others claim 10k, and some claim 15k is acceptable. For a while, BMW suggested changing the oil every 15,000 miles on their newer engines, however, this was revised in 2014 to 10,000 miles. Personally, we believe the cost of engine oil is relatively inexpensive compared to premature engine wear or failure, so we believe 5,000 to 8,000-mile oil change intervals (OCI) are best.
That being said, the oil is long-life approved (whatever that means) and is typically high-quality oil. If you extend a few oil changes to closer to 10,000 miles the engine is not going to suddenly detonate due to old oil alone. Additionally, gentle driving on highways at constant speeds will likely extend oil life, while aggressive driving and/or frequent city driving will likely shorten the life. Your driving style should dictate whether your personal OCI is on the higher or shorter end.
N20 Engine Oil Info
Weights: 5W-30 or 5W-40 recommended
Oil Consumption: ~1 quart per 850 miles
Oil Capacity: 5.3 Quarts (5L)
Recommended Maintenance Interval
5,000-6,000 miles for aggressive driving, or short trips/city driving
7,000-8,000 miles for gentle/moderate driving, or long trips/highway driving
**We highly recommend using LiquiMoly engine oils. It's excellent oil for the price, and is our oil of choice for all 3 of our BMW N54 engines as well as any other turbo BMW.
DIY: Depends on brand, roughly $30-40
**The oil filter should always be changed along with the oil**
3. Engine Coolant
BMW does not clearly state a coolant change interval for the BMW N20 as they claim the coolant is a “lifetime” fluid. Now I am not quite sure if BMW just expects the engine to explode before 100,000 miles so they consider it a lifetime fluid. We recommend flushing and replacing your N20 coolant every 60,000 to 80,000 miles or roughly every 5 years. The coolant itself is very inexpensive, and as such, the DIY crowd may want to change the coolant even sooner.
N20 Coolant Info
BMW approved coolant
Coolant Capacity: 7.1 Quarts (6.7L)
Recommended Maintenance Interval
60,000 to 80,000 miles
OR every 5-6 years
~$100 repair shop
Final Thoughts on BMW N20 Maintenance and Common Problems
As discussed throughout this article the BMW N20 is an overall reliable engine that does not have many common issues. The timing chain and components may be problematic on models prior to 2015, but has since been resolved with an updated design. Oil leaks from the valve cover/gasket and oil filter housing/gasket may begin to become prevalent prior to 100,000 miles due to wear and tear. Additionally, standard maintenance on the vehicle is pretty minor and inexpensive. Please do keep in mind – simply because something is listed as a common problem in this guide it does not mean it will indefinitely become an issue on every engine. Additionally, because something was not listed does not mean it may not become an issue on certain cars.
Often, reliability of each specific N20 engine may come down to how well it is maintained, as well as the luck of the draw. Some engines may make it past 100,000 miles without any significant issues, while others may cost thousands of dollars a year in repair bills. A well maintained BMW N20 engine should generally be a reliable, inexpensive engine to own, all while remaining enjoyable and sporty to drive.
What are your thoughts and experiences on the BMW N20 reliability?