2018 BMW 640i XDrive Gran Turismo Is Leaking Oil

Causes and Solutions for Oil Leaks in 2018 BMW 640i xDrive Gran Turismo

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
80% chance it's the
Oil System Components
0%
20% chance it's the
Engine Gaskets
The most common reasons a 2018 BMW 640i xDrive Gran Turismo is leaking oil are oil system component failure and leaking engine gaskets.
  • Oil System Components: A worn or damaged oil pump or filter can lead to low oil pressure, resulting in inadequate lubrication and potential engine damage.
  • Engine Gaskets: A worn or damaged engine gasket can lead to oil or coolant leaks, resulting in engine overheating or loss of lubrication.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2018 BMW 640i xDrive Gran Turismo is leaking oil?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

Oil pans don't wear out or break like other parts, they generally only need to be replaced because of external damage from an accident or an improperly tightened drain plug. The main symptom you will experience is an oil leak underneath the engine of your car. The oil that leaks from a damaged oil pan will range from dark brown to dark black. If the leak is large enough or occurs for long enough the oil level will be low enough to turn the oil pressure or low oil level warning light on.

A bad oil level sensor may cause a false reading of the engine oil level. The oil level warning light may illuminate even when the oil level (checked manually) is within an acceptable range. The warning light may also come on and off intermittently if the sensor is faulty. An error code may be sent to the PCM and a check engine light may come on the dashboard as well if the sensor is bad.

The engine oil pressure warning light will come on if the engine oil pressure is low, or if the oil pressure sensor is faulty. In either case, engine power may be reduced significantly. The check engine light may also illuminate, and an on-board diagnostic (OBD) trouble code will be stored in the vehicle's computer.

What steps should I take to diagnose the oil leak in my 2018 BMW 640i xDrive Gran Turismo?

To effectively diagnose an oil leak in your 2018 BMW 640i xDrive Gran Turismo, begin with a systematic approach that prioritizes simpler checks before moving on to more complex diagnostics. Start by locating the leak; inspect the area beneath your vehicle for any oil drips or pooling, and examine the engine and transmission for wet spots or stains. Next, check the oil level to determine if it is consistently low, which could indicate a leak. Focus on the oil filter and drain plug, ensuring they are secure and free from damage. Gaskets and seals are also critical components to inspect; look closely at the valve cover gasket, oil pan gasket, and camshaft seals for signs of wear or damage. If the source remains elusive, consider adding UV dye to the engine oil, as this can help illuminate leaks under a UV light. For a more thorough investigation, a pressure test on the oil system can reveal hidden leaks by pressurizing the system and observing any oil escape points. If these steps do not yield results or if you feel uncertain about the process, consulting a qualified mechanic is advisable, as they possess the expertise and tools necessary for accurate diagnosis and repair. By following this structured diagnostic approach, you can efficiently identify and address the oil leak in your BMW.

What are the common causes of oil leaks in a 2018 BMW 640i xDrive Gran Turismo?

When diagnosing oil leaks in a 2018 BMW 640i xDrive Gran Turismo, it's crucial to understand the common culprits that may be at play. One of the primary sources of leaks is the oil pan gasket, which can degrade over time due to exposure to heat and engine vibrations, leading to oil seeping out. Another frequent issue arises from the valve cover gasket, which can deteriorate and allow oil to escape from the top of the engine, often resulting in visible leaks on the engine block. Additionally, the oil filter housing gasket is another potential failure point; if this gasket fails, it can create leaks around the oil filter area, making it essential to check during oil changes. Timing cover leaks are also a concern, as they can occur due to wear or improper installation, leading to oil pooling in the engine bay. Lastly, issues with the oil cooler gasket can contribute to leaks, particularly if the gasket has become brittle or damaged. Addressing these issues promptly is vital to prevent further engine damage, and regular inspections can help catch these problems early, allowing DIY enthusiasts to take action before they escalate.

How urgent is it to address the oil leak in a 2018 BMW 640i xDrive Gran Turismo?

Addressing an oil leak in your 2018 BMW 640i xDrive Gran Turismo is a matter of urgency that should not be overlooked. Ignoring this issue can lead to a cascade of problems, including decreased oil levels that compromise the lubrication of critical engine components, potentially resulting in overheating or severe engine damage. Moreover, the environmental impact of leaking oil can be significant, as it poses a risk of contamination to the surrounding area. By taking swift action, you not only protect your vehicle from costly repairs down the line but also contribute to a healthier environment. While a professional inspection is advisable to accurately assess the leak's source and severity, the key takeaway is that timely intervention is essential for maintaining the performance and longevity of your BMW.

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