2018 Audi A4 Quattro Is Leaking Oil

Discovering the Causes of Oil Leaks in Your 2018 Audi A4 Quattro 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 2018 Audi A4 Quattro 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 Audi A4 Quattro 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 are the steps to diagnose the oil leak in a 2018 Audi A4 Quattro?

To effectively diagnose an oil leak in your 2018 Audi A4 Quattro, start by locating the source of the leak. Begin with a thorough inspection of the engine bay and the area where you typically park, looking for any visible signs of oil, such as puddles or drips. Pay special attention to common leak points like the oil filter, oil pan, and valve cover gasket. Next, check the oil level using the dipstick; a significant drop may indicate a leak. Inspect the oil filter and drain plug for any looseness or signs of leakage, as these are often culprits. Additionally, examine the gaskets and seals for wear or damage, which could also be contributing to the leak. If the source remains elusive, consider performing a pressure test to help identify leaks that are not immediately visible. Should you find the process overwhelming or the issue complex, consulting a mechanic or an Audi dealership for professional assistance is a wise choice. By following this diagnostic approach, you can systematically address the oil leak and ensure your vehicle remains in optimal condition.

What are the common causes of oil leaks in a 2018 Audi A4 Quattro?

When dealing with oil leaks in a 2018 Audi A4 Quattro, it's crucial to understand the common culprits that may be at play. One frequent issue is the valve cover gasket, which can deteriorate over time, leading to leaks around the valve cover area. Another potential source is the oil pan gasket, which may wear out or sustain damage, resulting in oil leaking from the engine's bottom. Additionally, camshaft seal leaks can occur as the seals age, allowing oil to escape from the camshaft region. The oil filter housing gasket is also a common point of failure, where leaks can develop around the oil filter area. Lastly, the rear main seal can become a problem as it ages, leading to oil leaks from the rear of the engine. Addressing these leaks promptly is essential to prevent further engine damage, and regular maintenance checks can help catch these issues early, ensuring your Audi A4 Quattro remains in optimal condition.

How urgent is it to address the oil leak in my 2018 Audi A4 Quattro?

Addressing an oil leak in your 2018 Audi A4 Quattro is not just a matter of routine maintenance; it is a pressing concern that requires immediate attention. Oil is vital for lubricating engine components, and a leak can lead to a significant loss of this essential fluid, resulting in inadequate lubrication and potential engine damage. Moreover, the presence of leaking oil creates a fire hazard, especially if it comes into contact with hot engine parts, which can ignite and lead to dangerous situations. Ignoring the leak can exacerbate the issue, leading to more extensive and costly repairs down the line. By promptly monitoring and addressing any signs of an oil leak, you not only safeguard your vehicle's performance but also enhance its longevity. Therefore, if you notice any oil leaks, it is crucial to take action immediately to ensure the safe and efficient operation of your Audi A4 Quattro.

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