Owning a car means that you are going to eventually be dealing with some mechanical issues. Oil leaks are one of those common problems to which most car owners can relate (unless you drive an EV). If you have spotted a puddle of oil under your car this morning or after doing some errands, you may be wondering, “Why is my car leaking oil when parked?” Is it a bad sign? Should you take a look under the hood ASAP? Here is everything you need to know about an oil leak when parked.
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What are the Common Signs of Oil Leaks?
In order to first diagnose whether you are dealing with an oil leak or not, it is important to search for some clues. Luckily, there are several common signs that point to an oil leak, so you can figure out what is going on relatively quickly.
Here are the things to look out for:
- Oil puddles or spots under your vehicle
- Smell of burning oil
- Low oil level
- Check engine light comes on
- Unusual engine noise
- Smoke from the engine bay with a bluish-white tint
Why is My Car Leaking Oil When Parked?
Oil leaks can be caused by a variety of factors and cause a number of symptoms. Now that you know what to look for, here are some of the reasons why your car is leaking oil when parked.
Faulty Gasket or Seal
One of the most common causes of oil leaks in cars is a faulty gasket or seal. These components are responsible for creating a tight seal between the various engine components, preventing oil from leaking out. Over time, gaskets and seals can become worn down, cracked, or damaged, leading to oil leaks. This can be exacerbated by extreme temperatures, which can cause the gaskets and seals to expand and contract, leading to more wear and tear.
Now, which gasket and seals are most likely to be the culprit? The valve cover gasket and camshaft or crankshaft seals.
The valve cover gasket is a thin piece of rubber that separates the cylinder head and valve cover. While its main purpose is to prevent oil leaks, it can be improperly installed or cracked from aging and heat. When that happens, you get an oil leak. Camshaft or crankshaft seals also work to keep oil from leaking, though when they fail, they do the exact opposite.
Check out this video to learn how to diagnose where an oil leak is coming from:
Damaged Oil Pan or Oil Filter Housing
The oil pan and oil filter are responsible for helping hold and circulate the oil through the engine. However, these pieces, though essential, will break down over time. For example, the oil pan can become cracked when driving down the road, causing oil to seep whenever the car is parked. Accidents can also damage the oil pan or oil filter housing, eventually causing leaks.
Improper installation (read as under- or over-torquing) may also impact your oil pan and oil filter. For instance, if you install the oil filter without ensuring that it is completely in place or screw it in too tightly, the housing will get damaged, and then the oil will seep out.
Faulty Oil Pressure Switch or Sending Unit
The oil pressure switch or sending unit is responsible for monitoring the oil pressure in the engine and sending a signal to the oil pressure gauge on the dashboard. As you know, low oil pressure can indicate a number of problems. Without average oil pressure, the lubricating qualities of oil will not work as well, leading to engine damage or failure.
Oil pressure switches and sending units do degrade, though, since they are exposed to high heat. Vibration also works against these components. When they fail, oil leaks may occur. In some cases, a faulty oil pressure switch or sending unit can cause a leak by allowing oil to escape from the engine through the switch or sending unit itself. This is because these components have seals that can become damaged or worn over time, allowing oil to leak out.
A faulty oil pressure switch or sending unit can also cause an oil leak by interfering with the operation of other components in the engine. For example, if the switch or sending unit is malfunctioning, it could cause the oil pump to operate improperly, which could lead to low oil pressure and an eventual oil leak.
How to Stop an Oil Leak
Regardless of the cause, oil leaks can be a serious problem for car owners. Not only can they lead to a loss of oil and decreased engine performance, but they can also be a fire hazard if oil drips onto a hot surface (oil is combustible). It’s important to address oil leaks as soon as possible in order to prevent further damage to your car. If you notice oil leaking from your car when parked, there are a few steps you can take to diagnose the issue.
- Check your engine oil level (by reading the dipstick). If the engine oil is low and you have recently performed an oil change, you can suspect that, yes, the puddle under your car is engine oil. You should also do a visible inspection of the ground under the car and visible oil in the engine bay.
- Identify where the leak is coming from. Some common areas to check for oil leaks include the valve cover gasket, oil pan gasket, oil filter, and oil pressure sending unit. You may also want to look around the camshaft/crankshaft or anywhere that rotates. When you find the cause, it is up to you to decide whether you can DIY it.
- Replace the seal or gasket. Make sure to use the correct gasket or seal for your car’s make and model.
- Tighten loose fittings and bolts. Be careful not to over-tighten bolts or fittings, as this can cause damage to the component or create a new leak.
- Repair or replace affected components. If the leak is caused by a damaged component, such as a cracked engine block or damaged oil pan, you may need to repair or replace the affected part. This may require more extensive repairs and should be performed by a qualified mechanic.
- Use an oil-stop leak additive. Is the leak minor? Then consider using an additive to soften and swell gaskets and seals, stopping the leak temporarily.
You can find more details in our extensive “How to Stop an Oil Leak” article.
Preventing Oil Leaks Under Car When Parked
Preventing oil leaks in your car can be challenging, but there are a few steps you can take to help reduce the risk of leaks. Regular maintenance is key, as it can help you catch potential issues before they become major problems. This includes regular oil changes, as well as inspections of the various engine components. Keep in mind, too, that you should not exceed 10,000 miles between oil changes. 5,000-7,500 miles between oil changes is recommended.
In addition, it’s important to take care when driving your car. Avoiding potholes, speed bumps, and other hazards on the road can help reduce the risk of damage to your car’s engine components. It’s also important to avoid overfilling your car’s oil, as this can lead to increased pressure in the engine and potentially cause leaks.
Final Thoughts on That Puddle of Oil Under Your Car
Hopefully, you now know the answer to the question: Why is my car leaking oil when parked? Oil leaks are a common problem that can be caused by a variety of things. From the improper installation of an oil filter to old and worn-out engine components, like seals and valves, leaks happen. If you suspect that your car is leaking oil when parked, do not wait to repair it. Low engine oil levels will negatively impact your vehicle’s performance. So be sure to have routine oil changes done!
Thinking about taking your car to a repair shop? Then you will need to know how much your oil leak repair may cost.