2018 GMC Terrain Is Leaking Oil

Discovering the Causes of Oil Leaks in Your 2018 GMC Terrain and How to Address Them Effectively

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Reviewed by
Bo Fader
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 GMC Terrain 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 GMC Terrain 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.

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 GMC Terrain?

To effectively diagnose an oil leak in your 2018 GMC Terrain, begin with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Start by locating the leak; inspect the ground beneath your vehicle for any signs of oil pooling or dripping, which can help you pinpoint the source. Next, examine the oil pan for any visible cracks or damage, as this is a common area for leaks. Ensure that the oil filter is securely installed and not the culprit, followed by checking the oil drain plug to confirm it is tight and leak-free. Additionally, inspect the gaskets and seals around the engine, as wear and tear in these areas can lead to oil leaks. Regularly monitoring your oil levels will also provide insight into whether there is a significant loss over time, indicating a leak. If these steps do not reveal the source of the problem, it may be time to consult a mechanic for a professional diagnosis and repair. By following this structured diagnostic approach, you can efficiently identify and address the oil leak in your vehicle.

What are the common causes of oil leaks in a 2018 GMC Terrain?

When dealing with oil leaks in a 2018 GMC Terrain, it's crucial to understand the common culprits that may be at play. One frequent issue is a degraded or damaged oil pan gasket, which can wear out over time and lead to leaks. Additionally, a faulty oil filter can also be a source of oil leakage, as it may not seal properly, allowing oil to escape from the engine. Another common problem is a worn-out valve cover gasket, which can deteriorate and result in oil seeping out. Furthermore, leaking oil cooler lines can develop over time, causing oil to escape from the system. Lastly, a damaged or improperly tightened oil drain plug can also contribute to oil leaks. Addressing these issues promptly is essential to prevent further engine damage and maintain the vehicle's performance. Regular maintenance and inspections can help you catch these problems early, ensuring your GMC Terrain runs smoothly.

How urgent is it to address an oil leak in a 2018 GMC Terrain?

Addressing an oil leak in a 2018 GMC Terrain is crucial and should not be delayed. Ignoring this issue can lead to severe engine damage, as oil is vital for lubrication and cooling. Without adequate oil levels, the engine may overheat or seize, resulting in costly repairs that could have been avoided with prompt action. Additionally, oil leaks can create hazardous driving conditions, such as slippery roads, increasing the risk of accidents. The longer you wait to fix the leak, the more extensive the damage can become, leading to a snowball effect of repairs and expenses. Therefore, it is essential to prioritize the repair of any oil leaks to maintain the vehicle's performance, ensure safety, and protect your investment in the long run.

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