Common Problems with BMW 645ci

The BMW 645ci 6-Series is a uniquely designed 2dr coupe with lots of luxurious features, advanced technology, a spacious interior, and a powerful engine. However, this excellent coupe that offers the ultimate driving experience has issues of its own. What are the common problems of the BMW 645ci?

Even though the BMW 645ci experiences several issues over the years, it has some common problems that users experience. Some of the common problems of the BMW 645ci are oil leaks, fuel pump problems, electrical faults, engine misfiring, ignition coils failure, coolant pipe leak, and much more.

What are some of the common problems with the BMW 645CI?

Oil leaks

Generally, oil leaks are common among BMW models. This issue is also common on the BMW 645ci model. Oil leaks on this car because of an oil system component failure and leaking engine gaskets. That’s why it is crucial to have your car inspected as recommended by BMW.

If the oil system parts such as gaskets wear out, the oil will start to leak. Depending on the gravity of the issue or worn-out parts, you may have to part with at least $1,200 to fix the issue.

Electrical faults

Another problem that is common with BMW 645ci is electrical issues. This problem is more rampant on the 2004 BMW 645ci. According to reports, the idrive system in the car cut on and off, making the car shut off. Additionally, the sensor alert may go off continuously. In some cases, you may even get false alarms, such as engine overheating.

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In such a situation, you may have to take your car for inspection at the BMW service center. Also, the sensors may not be working properly, causing the car’s computer to send false information.

Engine misfiring

Some BMW 645ci 6-Series users reported engine misfiring. This usually happens when there is a worn-out spark plug wiring, a malfunctioning crank position sensor, a vacuum leak, or even a damaged head gasket. To stop the engine from misfiring, the damaged or worn-out parts should be replaced or repaired.

Issues with lock door sensors

This is another common issue in all BMW models. After covering several miles with your BMW 645ci, you may start experiencing problems with lock door sensors. The door handle may operate as normal but the door won’t open. This is usually caused by a broken door wiring harness, faulty door lock switch, or a bad connector. 

Ignition coils failure

The work of the ignition coils is to amplify the relatively low battery voltage from 12v to a high voltage of tens of thousands of volts for the spark plugs. So, if the ignition coil in the BMW 645ci fails, it can cause damage to the catalytic converter or engine. As a result, it may lead to more serious repairs if it’s not replaced in time.

Fuel pump issues

The fuel pump helps to pump fuel from the fuel tank to the injection system and then to the motor. So, if the fuel pump fails, the car may not operate as needed. Some of the signs of a worn-out fuel pump include engine dying or difficulty starting the engine.

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Failing plastic transmission oil pan

Even though several issues such as a defective mechatronic unit, low transmission fluid level, bad idle control valve, and bad vehicle battery cause the transmission to go bad, that’s not the case with the failing plastic transmission oil pan in the BMW 645ci 6-Series.

The main reason that causes the transmission to fail is because of a low-quality plastic adapter that cracks over time. As a result, it causes oil to leak, leading to low transmission oil levels that affect how the transmission works.

Timing cover gaskets leak

After clocking over 80,000 miles with your BMW 645ci, you will likely face a timing cover gasket leak. This is because the timing cover gasket will be worn out. It’s advisable to replace the gasket cover every 60,000 miles. Replace the worn-out timing cover gasket with a new one.

Coolant pipe leak

The 2014 BMW 645ci is fitted with an N62 V8 engine that happens to have coolant leaks or antifreeze. A coolant leak can be from a weep hole leak or from the front part of the car engine. Regardless of where the coolant leak comes from, it is easy to fix and shouldn’t cost you a lot.

Convertible roof issues

Since BMW 645ci comes in either coupe or convertible body types, some issues can only be found in the convertible model. For instance, the BMW 645ci with a soft rooftop has issues operating the roof. Sometimes, the sensors of the convertible rooftop can fail, leaving the top open. This can be dangerous in bad weather.

2005 bmw 645ci problems


How long does the BMW 645ci last?

The BMW 645ci can reach up to 150,000 miles if it’s properly maintained. And if you adhere to all the scheduled service maintenance, the car can even clock over 200,000 miles. So, your driving habits and how you maintain your car will determine how long it lasts.

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Is the BMW 645ci reliable?

No, the BMW 645ci is among the least reliable cars. This is because this model normally comes with multiple issues that can be difficult to deal with. What’s more, since BMW parts are costly, the cost of repair and maintenance goes up exponentially.

What engine does the BMW 645ci come with?

The 2004 BMW 645ci comes with the N62 engine. This engine is a naturally aspirated V8 engine, meaning it is very powerful. Aside from that, it is a 4.4-liter engine that produces up to 325 hp and 330 lb-ft of torque.


If you’re planning to invest in the BMW 645ci, it is vital to know both the good and bad sides of the car. This car is luxurious, beautiful, powerful, sporty, and spacious. Nonetheless, it also has several issues that you should be ready to handle, such as oil leaks, engine misfiring, fuel pump issues, ignition coil failure, and much more.

All in all, the BMW 645ci 6-Series 2dr coupe is an excellent car with lots of exceptional features and fantastic performance. However, it is also quite unreliable and costly to maintain.

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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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