Engine Oil Leak Causes and Prevention Tips

Having an engine oil leak can be a lot more serious than you might think. Even a small leak can negatively impact the life and performance of your engine and can end up having some serious consequences if not taken seriously. In this article, we’ll discuss the common causes of engine oil leaks and the potential damage they can cause.

First off, you need to understand there are a myriad of reasons why your car may be leaking oil, and it’s imperative that you find the root cause of the leak before something more permanent happens. One of the most common reasons is worn-out gaskets or seals which are made of more brittle and easily damaged materials than the rest of the engine.

More prevalent in older cars, your seals and gaskets can get worn down from age, or become brittle and shrink due to exposure to heat and pressure over a long period of time.

Then there are either the gaskets on your oil pan or the pan itself has somehow become damaged or punctured. Your oil pan sits on the bottom of your engine and sometimes is scraped or damaged by rocks or even high speed bumps. These hazards can also knock the seals or gaskets loose creating small pin hole leaks that can be tough to spot with the naked eye.

In addition to gaskets, seals, and oil pans, other potential causes of oil leaks include damaged cylinder heads or engine blocks, worn-out piston rings, and overfilled or degraded engine oil.

So it’s important to know if your car does indeed have an oil leak, and if it does to address the leak head on and not wait until it gets worse or your engine finally blows up leaving you with a very steep mechanic’s bill. And so that doesn’t happen, we’ve put together all of this information on the causes and some preventative measures when it comes to oil leaks. We hope you find all of this helpful.

Causes of Engine Oil Leaks

As mentioned in the introduction, oil leaks can seem to spring up for all sorts of reasons. Sometimes you may never even understand why they happened. It could be faulty parts or you just got unlucky and someone somewhere didn’t do their job right. But regardless of why they are there, we need to understand some of the more common types of oil leaks so we can spot them and stop the leak before it becomes a much larger problem.

  • Damaged or Worn-Out Gaskets and Seals – Gaskets and seals are used to stop liquids coming out of places where two metal parts of an engine join together. They can be made out of anything from cork to rubber and are often the first places to look for an engine oil leak. These parts include the valve cover, timing cover, and oil pan, among others.
    Over time and simply from normal wear and tear they can easily become damaged or dry out and get brittle and shrink. When this happens they can no longer fit properly which leaves your engine susceptible to leaking oil.
    Under normal circumstances, gaskets and seals need to be replaced every 60,000 to 100,000 miles depending on the make, model, and age of the vehicle and how hard you work your vehicle.
    You can usually tell if they’re the culprit as you’ll plainly see where the oil is coming from, or you’ll smell burning oil when the engine is hot. All signs you have a leak and most likely it’s a seal or gasket to blame.
  • Faulty or Damaged Oil Pans – Your oil pan is where all of the engine oil is kept that isn’t circulating through the car’s oil system. When your car is not running, the oil collects here in the pan through gravity.
    And since the pan is on the bottom of the engine, it can easily get knocked or punctured by debris on the road leading to a leak. Even a good sized pothole can cause your gaskets to loosen and start leaking. So think about whether you remember any hard bumps and then start noticing the leak. It’s a good sign you should look there.
    To know for sure, you just have to crawl under your car and look for any dripping oil or oil stains coming from the pan, or where it meets the engine block. If you can’t see anything, look to see if there are any oil spots in the driveway that correlate with the position of the pan. You may need to clean the undercarriage to notice the leak better.
  • Overfilled or Degraded Engine Oil – Most people don’t realize that overfilling your oil can be just as bad as under filling it. Overfilling your oil causes too much pressure in your system and all that pressure needs to go somewhere, usually blowing out a seal or gasket to relieve the excess pressure.
    Then there’s degraded or super old oil that has broken down entirely and no longer has the proper viscosity. As it thins out, it is far more likely to find tiny gaps and holes to start leaking from that wouldn’t otherwise be a problem if the oil was fresh.
    To identify overfilled engine oil or contaminated oil, always check the dipstick to see if the reading shows there’s too much oil. And look at the color of the oil on the dipstick as well. Dark looking oil is no longer useful and needs to be changed. Your oil should look amber colored if it is still good.
  • Damaged Cylinder Heads or Engine Blocks – A damaged cylinder head or engine block is one of the more serious leaks you can have and usually requires replacing the parts which in all honesty are very expensive to replace. This can happen when there’s too much heat and the block or head warps and cracks leaving enough room for oil leaks to occur.
    You’ll know if this is the case because when it does happen, which isn’t normal by the way, your oil will have coolant mixed into it and so it’ll look milky when you check your dipstick, or in any puddle that is leaking. You might also have white smoke coming from the exhaust pipes or a sweet coolant smell in the engine bay. If this is the case, you need to get to a mechanic immediately!

Damage Caused by Engine Oil Leaks

Leaving an oil leak untreated for an extended period of time is never a good idea. Just because it may seem you’re only losing a little oil each day doesn’t mean it can cause a lot more additional damage to the motor.

Engine Damage: When your oil is low, the oil is no longer pulling heat away from the engine parts which will eventually lead to the parts overheating and possible warping. This can be very serious and can lead to the engine needing to be completely replaced.

Another problem with low oil levels is that there’s not enough pressure in the system to keep the oil circulating correctly which again, leads to engine parts that are overheated and not lubricated correctly. Best case scenario the parts take on a lot of unnecessary wear and tear. Worst case the engine stops working!

Transmission Damage: You may not realize it, but low oil levels can not only negatively affect your motor, but the transmission as well. The leaking oil can literally eat away at hoses and other transmission parts causing problems if you don’t have the situation corrected quick enough.

Cooling System Damage: The cooling system runs through the engine block just like your oil system. If there is an oil leak in the right place, oil can get into the coolant, contaminating it and causing a lot of additional problems. Once oil finds its way into your cooling system, the oil thickens the coolant to a point where it has trouble running through the system correctly, allowing your engine to overheat.

And that’s not to mention the damage that oil can wreak on the cooling system parts as they simply weren’t designed to have oil running through them. The oil can easily corrode, rust and destroy some of the cooling parts leaving you with an even bigger mechanic’s bill.

Repair Cost: How much you’ll need to shell out due to an oil leak really depends on the extent of the damage. Sometimes it’s just an oil filter that needs to be tightened and so there’s no cost at all. Or in more serious cases your block or head is cracked which can easily cost thousands to replace.

You really need to know where the oil is coming from to even get a hint of the amount it will cost to fix the problem. But one thing is for sure, the longer you wait to address the leak, the more it will probably end up costing you.

Obviously having an oil leak can be a serious problem, but normally it’s not. Especially if you notice and correct the problem quickly. And one of the best ways to be sure there isn’t a problem is to be doing regularly scheduled maintenance on your vehicle so you notice right away when something is off.

Prevention Tips for Engine Oil Leaks

Prevention is always better than any cure, even when it comes to oil leaks. Routine maintenance, oil changes, and regularly checking for leaks are the easiest ways to keep up with the condition of the engine and notice problems before they get more severe. Here are some tips to help prevent engine oil leaks:

Regular Maintenance

Regular maintenance is just smart no matter what your situation is. If you’re diligent about keeping up with regular oil changes, keeping your fluids at their proper levels and looking closely at your motor and noticing any sort of leaks or other problems goes a long way to making sure you don’t get a leak from the start. Plus regular maintenance rituals keep everything running the way it’s supposed to, so there’s less wear and tear which means all the parts will last longer.

Checking for Leaks

You should be visually inspecting for leaks every time you lift the hood of your vehicle. Not only that, always notice if there are any new spots in your driveway or where you park your car. These are always tell tale signs you have some sort of problem and it needs to be looked at. Always check the color of your oil as well and notice if it smells burnt or isn’t an amber color.

Using the Right Type of Oil

Your car was designed to run on a specific type of oil, and if you use something different you can end up doing a lot of damage.

For example, although synthetic oils are superior to their petroleum based counterparts, that doesn’t mean you should use them in a car that wasn’t designed to use them.

Synthetics are thinner than older types of oil, so the pressure they produce and viscosity are far different. If you are using them in a car that wasn’t designed for them, you can easily start getting oil leaks as the synthetics can pass through smaller cracks.

They also won’t give the correct pressure in your oil system leaving your engine parts starving for lubrication and wearing out faster than they were designed for. So always be sure you’re not mixing and matching the wrong oil for your car make and model.

Using Quality Gaskets and Seals

High-quality gaskets and seals are often made from different materials than the cheaper cork type ones you can get. They last longer and can withstand far more heat and pressure which means they won’t leak as quickly as other materials will. Just be sure you’re using the right ones for your car or truck.

Proper Installation

As we wrote before, sometimes it’s just human error that causes a leak like in the story of the oil change place that didn’t screw the oil filter on tight enough. Even professionals make mistakes sometimes. But if you do have work done by a professional, they’ll usually correct their mistakes if you notice them soon enough.

So there are five ways that you can hopefully prevent you from ever getting an engine oil leak. Prevention is always helpful for keeping an engine in good condition and avoiding such problems. Regular maintenance, checking for leaks, using the right type of oil, using quality gaskets and seals, and ensuring proper installation can all go a long way to make sure you never need to worry about having an oil leak in your car.

And if by chance you do notice a little oil spot in the driveway, don’t ignore it! Either do the checks we wrote about above yourself, or get your vehicle to a professional mechanic right away. If you don’t, you could be setting yourself up for a massive mechanic’s bill in the near future.


As you can see, engine oil leaks are pretty serious and should always be addressed as fast as possible. The amount of damage that you can cause by putting off fixing a leak because you think it’s too small to worry about or because you don’t realize the amount of damage they can do is just not helpful. You may get lucky and it’s something small, or maybe you find there’s a serious problem with the engine. Either way, it’s always better to know exactly what’s going on than to be guessing.


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