Common problems with BMW B48 engines

The BMW B48 engine is a turbocharged inline-four petrol engine that replaced the exceptional BMW N20 engine. This engine has been in production from 2014 to date. The first car to feature this engine was the F56 Mini Hatch which has been fitted in BMW applications since 2015.

Unlike the BMW N20 engine, the BMW B48 is slightly more reliable and durable. However, it also comes with several issues that interested users should know about. But what are the common problems with the BMW B48 engines?

Common problems with the BMW B48 engines are coolant loss, valve cover problems, failing spark plugs, cooling system problems, failing VANOS Solenoids, oil pan gasket issues, and high oil usage. However, since the BMW B48 engine has not been on the market for long, it doesn’t feature many issues like older engines.

What are the common problems with BMW B48 engines?

Coolant loss

This is the first issue that BMW drivers with the B48 engine should be ready to experience. Some of the things that cause coolant loss are a damaged radiator, a weak radiator cap, and a bad head gasket. So, if you’re having coolant loss, you should have the mechanic check these parts and fix them to avert the issue.

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Some of the signs of a coolant leak are leaked coolant under your car, poor gas mileage, coolant leaking into the engine oil, engine overheating, and a sweet aroma coming from your BMW’s hood.

Valve cover issues

This is another problem that will take place as your engine ages. The most notorious valve cover problem is leakage. When the valve cover wears out or cracks, it starts to leak. Signs of a cracked or leaky valve cover are oil running down your engine block and a burning smell coming from under the hood.

If your car has valve cover issues, you should have the mechanic attend to it quickly. Failure to do so may lead to major problems. 

Cooling system problems

Your car’s cooling system helps the engine to operate at an optimal temperature. Therefore, if one of the cooling system parts fails, the engine won’t run at its ideal temperature. Some of the things that cause the cooling system to have issues are a failing thermostat, natural buildup, or debris.

Symptoms of a failing cooling system are engine overheating, white exhaust smoke, poor quality coolant, coolant leak, warning lights, high reading on the temperature gauge, and decreasing gas mileage. Fix the primary issue to fix the cooling system problem.  

Oil pan gasket issues

The main cause of oil pan gasket failure is the oil from the pan falling on the exhaust manifold. If you don’t rectify this issue quickly, it may end up affecting others parts, such as the oxygen sensors. Have the mechanic fix this issue as fast as possible.

Failing spark plugs

Spark plug and ignition coil failure are common in BMW models. If your BMW B48 engine clocks over 30,000 miles, you should keep a keen eye on the spark plugs. These are usually replaced between 30,000 and 60,000 miles. On the contrary, the ignition coils should be monitored between 40,000 and 90,000 miles.

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Failing VANOS Solenoids

If your BMW has clocked over 50,000 miles, you should keep a close eye on the VANOS Solenoids. Solenoids become clogged between 50,000 and 70,000 miles. The main cause of VANOS Solenoid issues in BMW is failing O-rings. Since the O-rings are made from rubber, they can wear out and break down. 

High oil consumption

BMW engines not only use high-quality oil, but they also use a lot of oil compared to standard cars. The BMW B48 engine is not an exception. Therefore, you should be ready to spend a little more on oil compared to standard cars.

Video: WHY I BOUGHT A BMW 330i (B48) OVER A 340i (B58)


Is the BMW B48 engine reliable?

Yes, the BMW B48 engine is very reliable compared to similar BMW engines. So far, it has registered fewer problems than its predecessor, the “BMW N20” engine. Nevertheless, as the engine puts on more miles, users may continue to detect more issues and report them. Overall, it is a reliable engine with a low maintenance cost.

After how many miles does the BMW b48 engine start having problems?

The BMW B48 engine will start having issues as early as 30,000 miles. Hence, it is vital to adhere to BMW’s recommended maintenance service to ensure that your car doesn’t develop issues as early as 50,000 miles. Some of the things that you will keep an eye on are worn-out spark plugs and ignition coils.

How long does the BMW b48 engine last?

The BMW B48 engine is one of the most reliable BMW engines on the market. If properly maintained and cared for, it can last for more than 200,000 miles. However, the most serious problems will be experienced when the car hits over 150,000 miles. Ensure to change oil, rotate tires, and replace worn-out fluids as recommended by BMW.

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How much power does the BMW b48 engine produce?

The BMW B48 engines produce between 181 and 302 horsepower in stock form. The BMW 20i versions produce the least horsepower, while the 30i and 35i deliver the most horsepower. Note that the 302 hp B48 engines use a stronger crank, bearings, and pistons with a lower compression ratio.

On the contrary, the torque of the BMW B48 ranges between 214 and 332 lb-ft. Similarly, the 20i versions have the least torque, while the 35i version has the most torque.

What BMWs are fitted with the BMW B48 engine?

The BMW B48 engine is usually found in BMW models with the ending badge numbers 20i, 25i, 28i, and 30i. Nonetheless, the high-performance version of the BMW B48 engine can be found in a few 2019+ 35i models. Additionally, this engine can also be found in some Mini models and the Toyota Supra.


The BMW B48 engines are some of the most reliable on the market. Even if they have their issues, these engines are way more durable than their predecessors, such as the BMW N20 engine. If well-maintained, the BMW B489 engine can last over 200,000 miles.

One of the major issues that BMW B48 users should be ready to deal with is coolant loss and cooling system problems. Overall, it is a nice engine and slightly cheaper to maintain than most BMW engines.

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Edwin Odipo

Why do you love writing about cars? Cars make our lives easy. You can visit your distant friend, relative or even rush to the grocery store a few miles from your home with a lot of ease. Imagine how life was before the invention of cars?? To me, cars are a blessing that made life more convenient.

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