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Top 8 Reasons Why Your Car Might be Leaking Oil

January 10, 2020

On an ordinary day, as you’re leaving for work, you stop and notice – a pool of oil under your car. Even if it’s just a few drops, finding oil leaks under your car is unnerving. Plus, messy leaks can make your driveway look terrible.

Don’t ignore an oil leak. An engine leaking oil from the top or bottom is a serious issue. So, what’s a responsible car owner to do? Get the leak fixed, of course. A professional mechanic will be able to pinpoint the cause of the leak for you. But in the meantime, we’ll give you a few ideas about why your car might be leaking oil – and where it might be leaking oil from.

Why is my car leaking oil?

If your car is leaking oil one of the common places is from the oil pan gasket. But it may not be the oil pan gasket leaking oil. It could also be a timing belt cover leak or a camshaft seal leak. There are a number of possible explanations for an oil leak. But here are the 8 top reasons why your car might be leaking oil.

Common reasons why your car might be leaking oil

We’re going to get into the common reasons why your car might be leaking oil shortly. But first, a quick disclaimer: There are countless different types of cars on the road, all of which can develop leaks from a myriad of locations. As such, this list is not comprehensive – it simply covers some of the most common leaks, such as an oil leak from the timing cover and an oil leak in the front of the engine.

Engine oil leaks are usually the result of a bad seal or gasket, though they can be due to damaged parts, such as a cracked oil pan, as well. If you find your car leaking engine oil, the source may be one or more of the following:

1. Oil pan gasket

One of the most common locations for an oil leak is the oil pan gasket. As its name implies, the oil pan gasket provides a seal between the oil pan and engine block. If the gasket is leaking oil, this could indicate that it needs to be replaced.

2. Valve cover gasket

If the engine is leaking oil from the top, this could indicate that there is an issue with your valve cover gasket.

On top of your engine, you’ll find a valve cover protecting the components inside the cylinder head. As you probably guessed, a gasket provides a seal between the cylinder head and valve cover. It’s worth noting that Inline engines have only one valve cover (and valve cover gasket), whereas V-style engines have two. 

Over time, the valve cover gasket wears down and becomes less effective at sealing off the oil. If the area around the valve cover gasket is covered in oil, this means it’s time to replace the part

3. Front and rear crankshaft seals

The crankshaft is an internal engine component that protrudes slightly from both ends of the engine. By sticking out a bit, it can act as a mounting point for the external harmonic balancer and flywheel or flexplate. Seals, which prevent oil from leaking from the engine, sit at both ends of the crankshaft. Often, these are referred to as the front and rear main seals.

If a crankshaft seal leak is small, oil may start to accumulate on the underside of the engine. But if it’s a large leak, there may be a visible oil leak in the front of the engine.

4. Oil filter and oil drain plug

Every time you get your oil changed, the oil drain plug is removed then reinstalled. The oil filter is also replaced at the same time. Needless to say, because these components are tampered with so often, they are frequently the source of leaks.

5. Timing cover gasket or seal

Although some engines have a timing belt, most modern applications use a timing chain. The timing chain is lubricated with oil and a timing cover protects the timing chain. The timing cover gasket or seal keeps oil where it’s supposed to be: inside the timing cover.

Like many other car parts, timing cover gaskets wear down over time. As the gasket wears down, oil may start to escape from inside the timing cover. Sometimes, it’s the timing cover itself that is worn down, not the gasket.

If oil is leaking from the center of the engine near the front, it is typically a timing cover leak. But a mechanic will need to inspect your vehicle to determine whether the timing cover or timing cover gasket needs to be replaced to address your oil leak.

6. Camshaft seals

Camshaft seal leaks are common on engines that use a timing belt to keep the camshaft and crankshaft in sync. Much like the crankshaft, your car’s camshafts are on the inside of the engine. Overhead camshaft engines have two (or more) camshafts, both of which stick out a bit to provide a mounting point for the timing gears or sprockets. A camshaft seal fits around the end of each camshaft and prevents oil from leaking out of the engine.

If it is a camshaft leak, you should see oil on the rear of the engine below the valve cover. A large camshaft leak can cause smoke to start billowing out of the engine bay. Sometimes, you may even smell smoke without actually seeing it. A mechanic can inspect your vehicle to determine if a worn down or defective camshaft seal is responsible for your oil leak.

7. Cylinder head gasket

Head gaskets are more commonly known for causing internal leaks, which can result in issues such as coolant consumption and coolant-oil intermix. But head gaskets can leak both engine oil and coolant externally, as well. Flat engines – also known as boxer engines – are particularly susceptible to this problem (we’re looking at you, Subaru).

8. Oil filter adapter housing gasket or seal

Your car’s oil filter screws onto an adapter housing. And guess what? That housing usually has a gasket or seal behind it that can develop leaks. If your car has a cartridge-style oil filter, leaks may also stem from the oil filter housing cap or its seal.

But wait – the leak could be something other than engine oil 

You shouldn’t automatically assume that fluid leaking from your vehicle is engine oil. Just because it looks like engine oil, doesn’t mean it is engine oil. Your car has a lot of fluids and it can be hard to tell them apart – especially once they’ve hit the ground.

If you see a puddle underneath your car, the best way to determine whether or not it is an oil leak is to look at the color of the fluid. If it is clear, it is most likely water draining from your vehicle’s air conditioner system. If it is a bright green, pink, orange, or blue, it is likely coolant. This type of fluid may also have a sweet smell, which makes it easier to identify.

A transparent yellow or brown fluid is typically brake fluid. If the fluid is brown with a reddish tint, it is probably transmission fluid. Power steering fluid can also be red, so many people confuse this type of fluid with transmission fluid.  

Engine oil is light brown or black in color. If you see a puddle with light brown or black fluid, this indicates that your car is leaking oil.

For example, your car has transmission fluid, brake fluid, and coolant. Many vehicles also have power steering fluid, differential fluid, and transferase fluid. And all of those fluids have the potential to leak, due to worn out or broken parts.

Why are we telling you this? Because you don’t want to jump to conclusions when your car has a leak. Visit a professional right away so that they can diagnose and repair the leak for you. Fixing the problem will help keep your car healthy and happy. Also, you won’t have to hide your oil-stained driveway from the neighbors anymore.  

Can you drive a car with an oil leak?

You should not drive a car if the engine is leaking oil from the top or bottom. Why? Oil is a flammable liquid that can ignite under certain conditions. If the oil ignites, it could start a fire that could potentially destroy the vehicle. 

This isn’t the only reason why you shouldn’t drive a car with an oil leak. An oil leak can also cause the seals and rubber hoses to wear down prematurely, which means they may need to be replaced sooner than expected. 

Furthermore, you could lose all of your oil as a result of a leak. Even if it’s a small leak, it could quickly turn into a large leak while you are driving. Operating a vehicle that is low on oil could seriously damage the engine.  

For these reasons, it’s best to immediately stop driving your vehicle if it is leaking oil. Contact a professional mechanic as soon as possible to repair the oil leak and prevent further damage.

Are oil leaks expensive to fix?

The cost of repairs to fix an oil leak will vary depending on the underlying issue that is causing the leak.

For example, if you need to replace your oil pan gasket, this could cost a few hundred dollars. But a timing belt oil leak will cost more to repair. 

The price can vary significantly, which is why you should always ask for an estimate of the cost of repairs upfront.