Mercedes-Benz CLS450 Is Leaking Oil

Diagnosing Oil Leak Sources in Your Mercedes-Benz CLS450 and Recommended Repair Solutions

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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 Mercedes-Benz CLS450 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 Mercedes-Benz CLS450 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.

Troubleshooting Oil Leaks in a Mercedes-Benz CLS450

When troubleshooting oil leaks in your Mercedes-Benz CLS450, begin by conducting a visual inspection of the engine, focusing on the rear where common leak sources like the oil separator and cam plugs are located. Next, check the area around the oil fill cap for any signs of oil residue, as this could indicate a problem with the PCV system leading to excess crankcase pressure. Moving to the front of the engine, inspect the front seal, which is often misdiagnosed; a leak here can be more serious than it appears. Additionally, examine breather hoses for signs of wear, as hardened hoses can contribute to oil leaks. Finally, assess the condition of seals and gaskets, as worn or deteriorated components can compromise the integrity of your engine. By following this structured approach, you can effectively identify and address oil leaks, ensuring your CLS450 remains in optimal condition.

How to Diagnose and Fix Oil Leaks in a Mercedes-Benz CLS450?

When tackling oil leaks in your Mercedes-Benz CLS450, understanding common problems associated with the engine's lubrication system is essential for effective diagnosis and repair. One prevalent issue is the degradation of seals and gaskets, which can occur over time due to exposure to heat and engine vibrations. These components are critical in maintaining a tight seal, and any wear can lead to leaks. Additionally, the oil pan may develop cracks or loose bolts, further contributing to oil loss. It's also important to consider the possibility of a faulty oil filter or improper installation, which can lead to leaks at the filter connection. By familiarizing yourself with these common failure modes, you can more accurately identify the source of the leak during your inspection, allowing for a more targeted and efficient repair process. This proactive approach not only helps in resolving the current issue but also aids in preventing future leaks, ensuring the longevity and performance of your vehicle.

Why is it Critical to Address an Oil Leak in a Mercedes-Benz CLS450?

Addressing an oil leak in your Mercedes-Benz CLS450 is not just a matter of routine maintenance; it is a critical step in safeguarding your vehicle's performance and longevity. Ignoring an oil leak can lead to severe consequences, including catastrophic engine damage due to inadequate lubrication. As oil levels drop, essential engine components may experience increased friction, resulting in overheating and potential failure. This not only jeopardizes your vehicle's efficiency but also poses a significant safety risk while driving. Furthermore, oil leaks can have detrimental effects on the environment, contributing to pollution if left unchecked. By prioritizing the resolution of oil leaks, you not only protect your investment but also ensure that your CLS450 remains in optimal condition, preserving its resale value and enhancing your driving experience. Taking prompt action against oil leaks is essential for maintaining the integrity and safety of your vehicle.

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