Top Reasons Why Your Car Is Leaking Oil

September 15th, 2022 by

A greasy puddle of brown oil underneath your car, low oil level readings, and an oily engine can all point to an oil leak. But why does this happen? We explain the most common reasons your car may leak oil, how to prevent oil leaks, and what to do when you discover them. If you prefer to bring your car to a professional, click the button below to call our service department and schedule an appointment!

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Damaged Oil Pans or Pan Gaskets

top reasons car is leaking oil

Oil can start leaking from your vehicle if the oil pans or pan gaskets become damaged. While manufacturers make these parts tough to survive normal driving, rough roads or debris can cause damage. If these components get holes, the oil will simply flow through.

Worn Valve Cover Gasket

If oil leaks from the top of your engine, a worn valve cover gasket may be to blame. Valve cover gaskets experience wear and tear over time. As these components wear away, the seal between the cylinder head and valve cover becomes less effective. If you notice oil around a valve cover gasket, it’s probably time to replace this component. While inline engines have a single valve cover gasket, V-style engines have two, and if your vehicle has a V-style motor, monitor both valve cover gaskets for potential leaks.

Worn Oil Drain Plug

The drain plug sits at the base of your oil pan, preventing oil from moving through while it’s in place. Mechanics remove this plug to perform your oil change. Over time, the threads of the drain plug can become worn. A drain plug with worn threads won’t fit as neatly, so oil may leak out.

Worn Oil Filler Cap

The oil filler cap may become loose or damaged as it ages. When this occurs, the oil filler cap can’t do its job well. When the engine runs and generates pressure, oil can leak from around the worn filler cap.

Worn Rings or Valve Seals

Rings and valve seals keep oil where it’s supposed to be. These components can wear down over time and become less effective at doing their job. The oil will stay around your engine unless there’s also a hole in your gasket. Regularly checking your fluid levels and inspecting your engine are the best ways to detect these sneaky oil leaks.

Worn Crankshaft Seals

Your car’s crankshaft has seals at either end that prevent oil leakage from the engine. As your car ages, these seals may wear away and become less effective. Oil may pool on the underside of the engine if you have a small crankshaft leak. If the leak is more substantial, you might see oil on the front of the engine.

Worn Camshaft Seals

The seals on each end of a camshaft can be another potential source of leaks on older vehicles. When these seals wear away, they become less effective at preventing oil from leaking out of the motor. If your camshaft seals become worn, you may see oil on the back of the engine, just below the valve cover. As a camshaft leak grows, your car’s engine bay may start smoking. This smoke isn’t always visible, so pay attention to any unexplained smoky smells.

Worn Timing Cover or Timing Cover Gasket

Most modern vehicles have a timing chain instead of an old timing belt. A timing cover gasket keeps oil inside the timing cover, so the timing chain stays lubricated. Over time, the timing cover gasket can wear down. When it does, it can’t hold oil as effectively, and leaks may develop. Leaks can also occur when the timing cover suffers substantial wear and tear. If you spot oil leaking from the center of the front of the engine, a timing cover issue may be the culprit.

Blown Head Gasket

While internal fluid leaks are more common, a blown head gasket may cause an external oil leak. This problem usually occurs if the head gasket blows between the oil passage and the engine’s exterior. This is a common problem for vehicles with flat engines.

Worn Oil Filter Adapter Housing Gaskets or Seals

Whether your car uses a screw-on or cartridge-style oil filter, its housing can be a pressure point for leaks. The gaskets or seals for the screw-on filter housing can wear away and become less effective at preventing oil leaks. So can the oil filter housing caps and seals on cars with cartridge filters.

Incorrect Installations

The oil may seep out if an oil gasket, filter, or oil drain plug isn’t installed correctly. The oil pan gasket and valve cover gasket should be tight enough to create a good seal without being overtight. Uneven gasket installation can also cause a problem, with oil leaking out of the areas that don’t have a tight seal. Engine oil can also leak out of an oil filter that’s too loose. If a mechanic misaligns the threads when replacing the oil drain plug or doesn’t tighten the plug enough, the oil will leak from the oil pan.

How To Prevent Car Oil Leaks

Following the oil change schedule recommended by your car’s manufacturer can help prevent oil leaks. When you follow the oil change schedule, clean oil moves through your engine. This oil is free of dirt and debris that can put pressure on components such as valve seals and rings.

Trusting your oil changes to an experienced mechanic is the best way to ensure your components get installed correctly every time. These professionals also understand the best oil for your vehicle and location. An experienced mechanic will also inspect your vehicle and detect any issues causing leaks before you lose too much oil.

Oil leaks can damage your car’s engine, radiator, and air conditioner, so it’s important to promptly take care of them. As your car can leak oil for several different reasons, you’re best to put professionals on the case. Our experienced mechanics can assess your vehicle, fix the problem, and replace your lost oil, so you’re back on the road sooner. They can also manage routine services to minimize your risk of oil leaks. Call us or use our online booking system to schedule an appointment at our service center.

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