You pull out of your driveway and notice a deep dark spot that wasn’t there before. Uh, oh. You have a car leaking oil. Not only is this a telltale sign of trouble for your vehicle, but you also have motor oil stains to prove it.
So, what do you do? Well, you can take your car to a garage and deal with a big mechanic’s bill, or you can fix the oil leak yourself. Yes, it is possible to fix an oil leak on your car from home. Here is how to get started.
Why Is My Car Leaking Oil When Parked?
If you’ve ever owned a car that burns oil, you know that oil loss can be a sneaky, invisible beast. Sometimes, though, oil loss isn’t so sneaky, and chooses to present itself as an unsightly dark stain on your driveway instead. Before you degrease and pressure wash that stain away, take a look at these four components — one of them could be the culprit of your discolored driveway and oily automobile.
#1. Damaged Oil Pan Or Gasket
One of the most common reasons your car might be leaking oil is a damaged oil pan. The oil pan serves as a storage area for oil when the engine isn’t using it. The oil pan includes a gasket that isolates the oil pan from the engine block.
A damaged oil pan or gasket can cause an oil leak. These components are located at the bottom of the engine and can be damaged by road debris. Wear and tear can also damage or loosen them, which may result in a leak.
#2. Worn Valve Cover Gasket
Your car’s engine may have one or two valve gaskets that create a seal between the valve cover on top of the engine and the upper part of the cylinder head. If this valve cover gasket becomes worn, it could fail to keep oil from leaking.
The valve cover gasket can also harden and develop cracks over time, which can cause leaks. If you notice oil leaking from the top of the engine, it could indicate problems with the valve cover gasket. Typically, this part lasts between 20,000 and 50,000 miles before needing to be replaced.
#3. Loose Drain Plug.
A loose drain plug is another common reason your car might be leaking oil. Drain plugs, which are attached to the oil pan, allow oil to drain from the engine. If the drain plug becomes loose, the accumulated oil may leak.
If you notice oil leaking directly underneath the drain plug, this component may be causing the leak. You may also notice leaking oil soon after an oil change, which may have caused the drain plug to loosen.
#4. Faulty Oil Filter.
Oil filters help the engine oil stay clean by filtering out contaminants and debris. Over time, pressure can build up in the oil filter, which can cause it to rupture and leak. Installing the wrong oil filter or failing to install it properly can also cause oil leaks.
Like a loose drain plug, a faulty oil filter may become apparent after a recent oil change. Ensure the oil filter is correctly installed and sealed to prevent an ongoing leak.
#5. Missing or Damaged Filler Cap.
The oil filler cap is the area that has direct access to your engine for adding oil. To see if your car is leaking oil, remove the cap to check your oil levels. If the seal from the cap wears out, is loose, damaged, or missing, it will cause significant leakage.
Inspect the condition of the seal when you check your oil and replace the cap if it is broken or shows signs of wear.
#6. Faulty Rings or Valve Seals
Leaking or worn-out engine valve seals or rings can deplete your vehicle’s oil level. The seals are engineered to prevent oil from leaking out as it travels around the camshafts and valves. Often unseen, these leaks can result in engine misfires or other serious engine troubles.
#7. Bad Rear Main Seal.
If everything else checks out, it’s possible that your leak is stemming from one of those crucial seals we mentioned earlier. Your rear main seal is responsible for keeping oil from leaking out the rear of your engine, where it mates with the transmission.
Depending on the potential severity of your rear main seal failure, you may notice small drips when your car is shut off, and larger puddles when it is parked but still running. This is because your vehicle’s oil level typically sits lower than the rear main seal when it’s turned off. When running, however, oil circulates throughout your engine — a hot, pressurized environment.
Now less viscous and being flung every which way, your oil can slip past the rear main seal and into the bell housing of your transmission. Once the vehicle is shut off, oil drains back into the pan and stops exiting through the rear main seal, but the oil that accumulated in the transmission bell housing continues to drip out when parked.
So, if you primarily notice your car leaking oil when parked and running, it might be due to a worn-out rear main seal. Though it may be tempting to top off your oil and keep driving, faulty rear main seals should be replaced as soon as possible, as they can experience failure and rapidly leak oil.
Generally, the transmission must be removed from a vehicle that needs its rear main seal replaced, so this repair is definitely best left up to the professionals.
What does it mean when your car is leaking oil when parked?
Oil leaks manifest in many different ways, but if your car is leaking oil when parked, the vast majority of leaks are due to degraded engine gaskets, oil pan leaks, or bad oil seals and connections.
Your car’s oil pan is attached to the bottom of your engine. It holds the oil that lubricates the different parts of your engine when it is not in use. The oil drain plug, located at the base of the oil pan, must be loosened and removed in order to drain the old oil.
Oil pan and oil drain plug are located on the underside of your car. Engine gaskets are located between most metal pieces bolted together, including but limited to the oil pan, oil pan drain plug, head gasket, the rear main seal, etc.. These gaskets and seals are exposed extreme temperatures and the elements (such as road debris) which both cause wear and tear.
Other signs your car is leaking oil
What if your car isn’t leaking oil when parked, but the oil level on your dipstick keeps decreasing when you check it?
There are several signs that your car may be leaking oil:
- Blue smoke: If there’s blue smoke coming from your exhaust pipe, pull over. Oil may be leaking into your car’s exhaust manifold (the part of your engine that collects and directs exhaust gases) and your car is at risk of catching on fire.
- Overheated engine: Can low oil cause overheating? You bet it can! Remember: Oil is meant to lubricate the different parts of your engine while it’s running. If your car is low on oil, then that lubrication is gone, and your engine will begin overheating.
- The smell of burning oil: If you get out of your car after driving it and smell burning oil, oil may have leaked onto your already hot engine and burned.
- Car leaking oil after an oil change: If your car began leaking oil after you received an oil change, chances are that something went wrong during that process. The oil filter might not have been fitted correctly or gotten pierced, the oil filler cap might have broken or been left loose, or the gaskets or drain plugs might have been over tightened or left loose.
How To Fix an Oil Leak
In order to fix an oil leak, the leak must first be identified. Though there are several items on the market to help resolve oil leaks, the best way to ensure the issue is resolved is by taking your vehicle to your local service center.
Identifying the primary cause of the leak is crucial to your engine. However, not all oil leaks are visible. For that reason, it’s imperative that you check your engine’s oil levels often between oil changes:
- Make note of the levels to determine how much oil your engine may be losing.
- Check your oil when the engine has not been running for at least 30 minutes, giving time for the oil to settle back into the pan.
- While the engine is off, remove the dipstick, wipe it off with a clean rag, and place the dipstick back in.
- Remove the stick again and read the level indicator. Levels that measure full or slightly below full are acceptable. Anything less than that will indicate the necessity for a top off. If the level is consistently low, this could indicate a serious problem and should be addressed immediately by a trusted technician.
No matter the cause, it is imperative to fix an oil leak as soon as one is identified. If you notice your car is leaking oil when parked, see oil on the engine itself, notice a smell of burnt oil or smoke, or notice falling oil levels, bring your vehicle to the nearest Auto care. By being proactive and repairing the leaks sooner rather than later, you may be able to prevent major engine damages.