Among the cars you've asked about during live streams, BMW F20 and F30 models are the most frequently mentioned. If you're planning to buy one of these, you'll generally encounter two engine options in the accessible gasoline models: the N13-coded 1.6-liter 4-cylinder and the B38-coded 1.5-liter 3-cylinder.

Since the N13 is an older engine and has been used by more people for longer periods, its problems are more widely known and discussed. Additionally, because the N13 was co-developed with PSA (Peugeot-Citroën), it's more prone to criticism by car enthusiasts, whereas the B38 is entirely BMW's in-house production. Despite this, it’s also true that the B38 engines are a step back in terms of performance compared to the N13.

Let's dive into the technology, common issues, and solutions of these two engines and compare them.

N13

The N13 engine is part of the Prince (THP) engine family, co-developed by BMW and PSA. Introduced in 2011, the 1.6L 4-cylinder engine was designed to be lightweight, turbocharged, and highly efficient. It features technologies like a twin-scroll turbo, direct injection, VANOS (variable valve timing), and VVL (variable valve lift).

BMW and MINI models using the N13:

– BMW 1 Series (F20)

• 114i (2012–2015, 102 PS)
• 116i (2011–2015, 136 PS)
• 118i (2011–2015, 170 PS)
• 120i (2015–2016, 177 PS)

– BMW 3 Series (F30)

• 316i (2012–2015, 136 PS)
• 320i (2012–2015, 170 PS)

– MINI Cooper (R56), Convertible (R57), Clubman (R55)

• Cooper (2011–2014, 122 PS)
• Cooper S (2011–2014, 184 PS)

Common Issues and Solutions for N13:

1. Timing Chain Problems: The chain can elongate, and the tensioner may fail, leading to mistimed valve operation. Solution: Regular checks and early replacement of the camshaft chain and tensioner are recommended.
2. Coolant Leaks: These can arise from cracked plastic reservoirs or faulty water pumps. Solution: Replace the reservoir and monitor coolant levels. Preventively replace the water pump to avoid future issues.
3. Ignition Coil Failures: Coil failures cause the engine to misfire or run rough. Solution: Replace all coils and spark plugs together to ensure smooth operation.
4. Turbo Hose Cracks: Turbo pressure can cause the charge pipe to crack. Solution: Use reinforced aftermarket parts to prevent recurrence.
5. High Oil Consumption: This can increase with age, especially in older engines. Solution: Shorten oil change intervals and regularly check oil levels.
6. Carbon Build-up: The direct injection system can cause carbon deposits to accumulate on the intake valves. Solution: Carbon cleaning is recommended every 80,000 km to prevent this.
7. Water Pump and Thermostat Failures: Early wear on these components can lead to engine overheating. Solution: Replace the water pump and thermostat every five years.
8. VANOS Solenoid Failures: The solenoids controlling the variable valve timing can fail, causing engine warning lights to come on. Solution: Replace the solenoids when they fail.

B38

The B38 is a 1.5-liter 3-cylinder engine introduced by BMW in 2013 as part of their modular engine family. It incorporates TwinPower Turbo technology and features a single-scroll turbocharger, direct injection, and VANOS (variable valve timing). This engine is known for its compact structure and fuel efficiency.

BMW and MINI models using the B38:

• 2015–2019: 116i, 118i (F20/F21)
• 2015–2021: 218i Active Tourer (F45/F46), 318i (F30/F31 LCI), X1 sDrive18i (F48)
• 2017–present: 118i (F40), 218i Gran Coupé (F44), 225xe Active Tourer PHEV
• 2014–present: Mini Cooper (F55/F56/F57), Clubman (F54), Countryman (F60)

Common Issues and Solutions for B38:

1. Carbon Build-up: The direct injection system can cause carbon deposits to accumulate on the intake valves. Solution: Carbon cleaning is recommended every 80,000 km to prevent this.
2. Water Pump and Thermostat Failures: Early wear on these components can lead to engine overheating. Solution: Replace the water pump and thermostat every five years.
3. Turbo Cooling Leaks: O-rings in the turbo cooling system may wear out and cause leaks. Solution: Regularly check and replace the seals to prevent leaks.
4. VANOS Solenoid Failures: The solenoids controlling the variable valve timing can fail, causing engine warning lights to come on. Solution: Replace the solenoids when they fail.
5. Oil Leaks: Leaking seals or gaskets may cause oil leaks. Solution: Replace seals and gaskets as needed, and monitor oil levels frequently.

Which One to Choose?

When it comes to making a choice between the N13 and B38, the decision depends on your driving habits:

• If you only use your car for daily commuting, don’t push the engine too hard, and regularly service the car with original parts (especially being conscious about oil changes), the B38 will likely be the better option due to its newer design and fuel efficiency.
• However, if you plan on modifying the car to achieve over 200+ horsepower, upgrading critical components (thermostat software to lower the water temperature, a larger intercooler, etc.) and are ready to use high-quality aftermarket parts, the N13 is more suitable due to its 4-cylinder design, which is generally more performance-oriented.
• For enthusiasts planning to take their car to the track or participate in racing events, neither engine is ideal, as both have their limitations when pushed to extreme performance levels.

In any case, pay close attention to the maintenance history and the condition of any used BMW you plan to buy.

Every problem has a solution; whether it is worth solving is the real question.

Sources:

https://en.wikipedia.org/wiki/Prince_engine

https://en.wikipedia.org/wiki/BMW_B38_engine

https://news.bgautomotive.co.uk/all-you-need-to-know-about-the-psa-prince-engine-n12-n13-n14-n18-ep3-ep6/

https://lifeonfour.co/engine-problems/bmw-n13-engine-reliability/

https://www.wapcar.my/news/bmw-b38-engine-maintenance-and-common-problems--3s-definitely-not-a-crowd-66615

https://carcaresite.com/bmw-b38-engine-problems/