2012 BMW 135i Is Leaking Oil

Discovering the Causes of Oil Leaks in Your 2012 BMW 135i and How to Address Them Effectively

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Reviewed by
Aisha
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 2012 BMW 135i is leaking oil are oil system component failure and leaking engine gaskets.
  • Oil System Components: A failure in oil system components, such as a worn oil pump or clogged oil filter, can lead to 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 2012 BMW 135i 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.

An oil leak may be noted on the ground where the vehicle is parked. However, many vehicles have plastic trays underneath the engine that may catch leaking oil and conceal the leak. In such cases, a low oil level, a burning oil smell, or even smoke from oil burning in the engine bay may be noted.

»MORE: Signs of a bad oil pan gasket

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 2012 BMW 135i?

To effectively diagnose an oil leak in your 2012 BMW 135i, start by conducting a thorough visual inspection of your vehicle. Begin by looking for oil spots on the ground where you typically park, as these can indicate the presence of a leak. Next, open the hood and examine the engine components, paying close attention to common leak points such as the valve cover gasket, oil filter housing, and oil pan gasket. If you notice any signs of oil accumulation or wetness around these areas, it may point to a specific source of the leak. For a more precise diagnosis, consider using a diagnostic kit that includes dye and cleaning agents, which can help highlight the leak's origin. If your inspection reveals oil in more complex areas, such as the turbocharger oil lines, it may be necessary to seek assistance from a trusted BMW specialist who can provide a more in-depth analysis. By following this structured approach, you can efficiently identify the source of the oil leak and determine the best course of action for repairs.

What are the common causes of oil leaks in a 2012 BMW 135i?

When dealing with oil leaks in a 2012 BMW 135i, it's essential to understand the common culprits that may be contributing to the problem. One of the primary sources is the valve cover gasket, which can wear out over time, leading to oil seeping from the top of the engine. Another frequent issue is the oil pan gasket, which can deteriorate and cause leaks from the bottom of the vehicle, often noticeable by oil spots on the ground. Additionally, the rear main seal is a critical component that, if failing, can result in significant oil leaks between the engine and transmission. The oil filter housing gasket is also a common point of failure, and if it is compromised, it can lead to oil leaks that may be mistaken for other issues. As your BMW ages, it's important to keep an eye on all gaskets and seals, as they can degrade and allow oil to escape from various locations. For those looking to tackle these issues themselves, a thorough inspection of these components can help identify the source of the leak, but if the problem persists, consulting a professional mechanic is advisable to ensure a proper fix.

How urgent is it to address the oil leak in my 2012 BMW 135i?

Addressing an oil leak in your 2012 BMW 135i is not just a matter of routine maintenance; it is an urgent issue that demands immediate attention. Oil is vital for lubricating engine components, and a leak can lead to dangerously low oil levels, resulting in overheating and severe engine damage. Moreover, oil that drips onto hot engine parts can create a fire hazard, posing a significant safety risk. Ignoring the leak can escalate the problem, leading to more extensive damage and costly repairs down the line, as the oil can harm surrounding components. If you notice oil pooling under your vehicle or hear unusual sounds like sizzling, it is crucial to act quickly and consult a qualified mechanic. By addressing the leak promptly, you not only safeguard your vehicle's performance but also protect your investment and ensure your safety on the road.

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