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Engine Oil Leak: All the 7 Possible Causes is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees by advertising and linking to Our endorsements are strongly based on our intensive research online and we do not accept sponsorships or gifts from brands in return. Learn more.

    Have you been noticing a few drops of oil on your driveway?

    Well, that’s most probably an engine oil leak. But a seepage or a puddle 1-2 inches in diameter isn’t an immediate threat to your engine—unless it’s been happening for days or weeks.

    However, in any case, getting the oil leak fixed as soon as possible is necessary. Driving with low engine oil is always bad for the engine, and the aftereffects can range from a drop in engine performance to seizing the engine while in operation.

    Now, let’s see all the possible causes of an oil leak.

    What causes engine oil leak

    The cause of an oil leak can range from an improperly tightened oil drain plug to a faulty or clogged oil filter or cracked gaskets. Unlike ignition system issues, identifying the cause of the engine oil leak is often straightforward. 

    You just need enough time to open the hood and check the different components. Plus, you need to know the components and reasons that can lead to an engine oil leak in a car—and here they are:

    1. Broken gaskets

    A gasket is a mechanical seal made of urethane or rubber(and sometimes metal) that seals the space between two surfaces or components in contact, preventing oil leaks. Since these gaskets experience high temperatures, pressure, load, and friction continuously, they can harden and undergo wear and tear.

    The engine oil leaks through when these gaskets are broken or cracked due to wear and tear. 

    There are four gaskets in the engine that can cause an oil leak:

    Valve cover gasket

    The valve cover gasket is located between the engine and the valve cover. If you find oil leaking between the engine and the valve cover, you’ll have to replace the valve cover gasket. 

    If the oil leaks from the valve cover, ensure the valve cover is in shape—aluminum valve covers can crack, and steel valve covers can warp.

    Cylinder head gasket

    The cylinder head gasket is located between the cylinder head and the engine block. If you find oil leaking from this area, it’s better to take it to a good mechanic. Replacing the head gasket is a time-consuming process and needs expertise.

    replacing cylinder block gasket to fix car oil leak
    The cylinder block gasket of a three-cylinder engine

    More often than not, a broken head gasket means many other components are worn out and need replacement. Head gasket wearing out is rare, and it usually happens due to engine overheating.

    Timing cover gasket

    The timing cover secures the front section of the engine block and protects the timing components of the engine. The timing cover gasket is placed between the engine block and the timing cover. 

    It is generally buried under fans and belts, making it hard to inspect. But if you see oil leaking from this area, you need to inspect both your timing cover gasket and camshaft seal.

    Oil pan gasket

    The oil pan is located under your engine, and this is what your oil drain plug is attached to, so you can inspect it from the bottom of your vehicle. If you see that the oil is leaking from the oil pan gasket area, you’ll have to replace the oil pan gasket (or the oil pan itself).

    But if the oil is leaking from above the oil pan, it is likely that one of the gaskets mentioned above is causing the oil leak. 

    2. Cracked crankshaft or camshaft seal

    Apart from gaskets, there are several seals in your engine that keep the engine oil from leaking, such as the crankshaft seal and camshaft seal. Like the gaskets, these seals also wear out or crack, causing an engine oil leak. 

    If the camshaft seal is damaged, you’ll see oil leaking behind the timing cover. Note that an oil leak around the timing cover can be due to a faulty timing cover gasket as well. 

    Diagnosing a faulty crankshaft seal or camshaft seal properly is tricky. It’s better to consult a professional mechanic.

    3. Faulty or clogged oil filter

    A clogged or damaged oil filter can also cause an oil leak, but it is generally less common than oil leaks due to gasket failures or faulty seals. 

    When you skip consecutive oil filter replacements, dirt and dust can accumulate in the oil filter. At first, the bypass system of the oil filter becomes active, and oil keeps flowing through the engine without getting filtered. Later, this results in an engine oil leak from the oil filter area.

    Read more about the symptoms of a clogged oil filter here.

    4. Damaged oil pan

    As mentioned earlier, the oil pan sits at the bottom of the engine. It can get easily damaged if the car hits a speed breaker, road debris, or due to accidents. 

    Oil leaks due to a damaged oil pan can be identified easily—there will be big puddles of oil under the vehicle that you’ll only think about getting it repaired on the spot.

    5. Improperly tightened oil drain plug

    Oil leaks due to loose oil drain plugs are very common. Oil will be leaking around the oil drain plug. You only need to tighten it and refill the engine oil if too much oil is lost. 

    However, an over-tightened oil drain plug can also result in an engine oil leak over time, as it can damage the threads. You need really strong hands to make that happen, though. 

    6. Excess oil in the engine

    Excess oil in the engine can also cause an engine oil leak from your car. Make sure you always keep the manufacturer-recommended oil levels. Note that manufacturer-recommended levels can be different from what an engine oil brand offers in a bottle. 

    In most cases, the engine oil light on the dashboard won’t be lit up when there’s excess oil in the engine. To check whether you have excess oil in the engine, use a dipstick tube. 

    7. Driving in extreme conditions

    You already know that cars running on the beach side usually corrode quickly because of the salty air. As the engine components corrode, it results in an oil leak.

    Similarly, excessive acceleration in colder weather can strain the engine components, such as gaskets and seals, leading to faster wear and tear and hence an oil leak.

    Car engine oil leak: FAQs

    Is it OK to drive a car with an oil leak?

    If the puddle is only 1-2 inches in diameter, there’s no problem in driving the car to a mechanic. But if there’s a large puddle and too much oil is lost, it is better not to drive the car until it is fixed. Driving with low engine oil can cause faster wear and tear and can damage other engine components.

    How much does it cost to fix an oil leak in a car?

    It can range from $50 to $1000, depending on the cause of the oil leak. If it is a clogged oil filter, you can replace it yourself for under $50. But if it is due to a gasket failure, it can cost $1000 or even more, depending on your brand and how serious the damage is.

    How serious is an engine oil leak?

    An oil puddle of only 1-2 inches in diameter under your vehicle is not an immediate concern. But if it is a large puddle, it should be repaired quickly and it is better not to drive it until it is fixed, as driving with low oil can further damage the engine.

    What 3 things can cause an oil leak?

    A gasket failure, crankshaft seal or camshaft seal failure, and a clogged oil filter can cause an oil leak. A damaged oil pan and an improperly tightened oil drain plug can also be the reason behind the oil leak.


    • An engine oil leak can be due to cracked or broken gaskets, a cracked crankshaft seal or camshaft seal, or a clogged oil filter. A damaged oil pan, an improperly tightened oil drain plug, excess oil in the engine, and consistently driving in extreme conditions can also cause engine oil leaks in cars. 
    • A small oil leak is not an immediate concern, but it needs to be repaired as quickly as possible. However, if there’s a large puddle of oil under your vehicle, it’s better not to drive it until it is repaired, as running on low oil can damage other engine components.