Is your car leaving behind a trail of oil spots?
Engine oil leaks are messy and can be potentially catastrophic for your engine as well as personal safety.
Wondering what’s causing your car engine oil to leak?
Keep reading to explore the top 12 causes of an engine oil leak, warning signs to spot them quickly, and some surefire ways to fix such issues.
This Article Contains:
- Top 12 Causes of an Engine Oil Leak You Should Watch Out For
- How Serious is an Engine Oil Leak?
- How to Fix and Prevent an Engine Oil Leak?
- 4 FAQs Related to an Engine Oil Leak
Top 12 Causes of an Engine Oil Leak You Should Watch Out For
Here are the most common causes of an oil leak:
1. Bad Oil Filter
Since an oil filter traps contaminants, it can get clogged with debris. This restricts the flow of oil and causes it to spurt out.
Additionally, an incorrectly installed oil filter can cause an engine oil leak. Sometimes, internal engine pressure can further aggravate such leaks if the oil filter isn’t installed correctly. So, check if the oil filter is loose or displaced, especially if you notice an oil leak after a recent oil change.
Pro tip: Replace your oil filter every three to six months or after 5,000 to 10,000 miles.
2. Broken Gaskets
Gaskets (mechanical seals) fill the space between two or more mating surfaces, preventing an oil leak.
They include:
- Valve cover gasket: This seal is located between the valve cover and the cylinder head in an engine to stop oil leaks.
- Cylinder head gasket: This seal between the engine block and the cylinder head ensures no coolant or oil leaks into the cylinders.
- Timing cover gasket: This seal is placed between the engine block and the timing cover. It prevents oil leaks and protects the timing belt from contaminants.
- Oil pan gasket: This seal is located between the oil pan and the engine block. It keeps the engine oil from leaking out of the oil pan.
Over time, the valve cover gasket, cylinder head gasket, etc., wear out due to friction, compression, oil pressure, and high temperatures. These compromised gaskets can cause a motor oil leak.
3. Cracked or Dried-Out Seals
Like the timing cover gasket, your vehicle also comprises several oil seals like the camshaft and crankshaft seal. These seals keep the engine oil from spilling.
Eventually, they can dry out, crack, or get damaged, causing a motor oil leak.
Note: Diagnosing a camshaft or crankshaft seal leak is tricky, so it’s best to get professional help.
4. Loose or Over-tightened Oil Drain Plug
A loose oil drain plug is a common reason for a car oil leak, but it’s likely to happen if you’ve fastened it by hand. In such cases, the oil drain plug may come undone while driving, resulting in an oil leak.
In contrast, over-tightening the oil drain plug could damage the threads, eventually causing an oil leak.
5. Broken Oil Filler Cap
The filler cap of a car’s oil tank often gets loose or breaks due to wear from constant removal and reinstallation. When this happens, you’ll notice oil puddles under your vehicle and a lit check engine light. You should either tighten or replace the oil filler cap.
6. Damaged Oil Pan
Since the oil pan sits underneath your vehicle, it can easily get damaged due to road debris or hitting a speed bump.
Typically, a cracked oil pan will result in a significant leak, leaving puddles of oil under your vehicle. You might also hear knocking and ticking noises from the engine.
7. Excess Oil in Your Engine
If you notice oil leaking from your car, it can be due to an overflow of excess oil or a spill during an oil change.
In case of an overflow, you’ll notice an oil puddle under your car, but the engine oil light on your dashboard won’t light up.
8. Cracked Oil Pressure Sensor
The oil pressure sensor, located in the cylinder head or engine block, can sometimes crack due to engine pressure and overheating, resulting in a leak.
Regularly inspecting the oil pressure sensor can help prevent such oil leaks.
9. Oil Cooler Leakage
If you notice oil leaking from the front of the engine, it’s likely from the engine oil cooler. This happens because the plastic sealings can crack, causing an oil leakage.
You can stop the leak by replacing the plastic sealer.
10. Blocked Crankcase Ventilation
The crankcase is typically ventilated through a valve and a hose connected to the intake manifold. It helps prevent overpressure inside the crankcase due to the car’s compression.
If this ventilation becomes clogged, it can lead to engine overpressure and leaks as the oil tries to escape.
11. Irregular Oil Changes
If you don’t get an oil change service regularly, it can lead to a buildup of dust, debris, and metal particles, which can thicken the oil. Thicker oil exerts pressure on the oil gasket seal, which may weaken the seal and result in a car oil leak.
Moreover, engine oil contains several additives, like cleansing detergents, anti-rust, and friction-reducing agents. These additives break down over time, making your engine parts more susceptible to an oil leak.
12. Driving in Extreme Conditions
Driving in high saline places or freezing temperatures could also cause an engine oil leak.
Why?
Salt and moisture corrode the metal components, resulting in more frequent engine oil leaks. On the other hand, long drives or excessive acceleration in cold conditions can strain the gaskets, seals, and other engine components. This reduces their durability, causing oil leakage.
Next, let’s review the safety concerns a motor oil leak poses.
How Serious is an Engine Oil Leak?
An engine oil leak is a pretty concerning issue that shouldn’t be ignored. Here’s why:
1. Fire and Safety Hazard
An engine oil leak leading to fire is rare (but possible). The average engine temperature ranges between 190 to 220 ℉, while engine oil ignites at 300-400 ℉.
Driving with a low engine oil level could cause a sudden spike in engine temperature, increasing the chances of engine oil burning.
2. Engine Damage
Sometimes, a small leak can gradually lead to the engine oil level dropping below the minimum mark.
If neglected, the lack of lubrication and accumulation of debris can cause the engine’s rubber hoses or seals to deteriorate from the heat. This can damage the car’s radiator and HVAC system (heating, ventilation, and cooling system) and lead to permanent engine damage.
3. Pollution
Used engine oil contains toxic agents like lead, zinc, and arsenic. If this leaked oil gets absorbed into water or sewage systems, it can contaminate waterways.
4. Health Risk
Exposure to leaking engine oil can cause health issues, including skin rashes, headaches, tremors, and even serious conditions like skin cancer.
Avoid unnecessary contact with used engine oil, and if you have to, wear protective clothing that is regularly cleaned or replaced.
Now that you know how dangerous car oil leaks can be, let’s find out how to prevent it.
How to Fix and Prevent an Engine Oil Leak?
Fixing an engine oil leak is complex. However, here are a few ways to prevent car oil leaks or resolve the issue:
- Inspect the oil pan for unsecured bolts, which can loosen over time and cause leaks. Check the bolts on the timing belt and valve covers too.
- If the oil drain plug is correctly installed, inspect the vehicle’s undercarriage to determine the root cause of the engine oil leak. For example, a gasket’s seal might be compromised or the O-rings on the cartridge oil filter may be incorrectly installed.
- You can use an additive like the STP Engine Stop Leak. It softens a rubber hose, seal, or oil cap if there’s a small leak.
- Use the recommended type of oil as specified in the owner’s manual to maintain good engine health.
- Regularly inspect your car to promptly address any leaks that may occur.
If the cause of oil leakage is severe or remains undetected, get a mechanic’s help to resolve it.
Got more questions related to oil leaks?
Keep scrolling!
4 FAQS Related to an Engine Oil Leak
Here are the answers to some commonly asked questions about engine oil leaks:
1. What Are the Common Signs of an Engine Oil Leak?
Here are five tell-tale symptoms of your car leaking oil:
- Oil puddle in your driveway: Dark brown or yellow puddles in your driveway or parking spot indicate an engine oil leak.
- Lit low engine oil light: An illuminated low engine oil light indicates low oil pressure. It can occur when your vehicle is low on oil or has dirty oil.
- Engine overheating: An engine oil leak can lead to a rapid decline in your engine oil level. Without adequate oil, the piston ring will grind against other engine components, resulting in your engine overheating.
- Engine smoking: Oil leaking onto the exhaust manifold can burn upon contact and produce smoke. This occurs when the engine block is overheated due to a low oil level.
- Smell of burning oil: When leaking oil drips onto heated engine parts, you’ll get the odor of burning oil from your car or hear a sizzle.
Note: The burning oil smell can occur due to a faulty valve cover, broken oil filter, or damaged engine oil pan leaking oil.
2. How Much Does it Cost to Fix an Engine Oil Leak?
Repairing engine oil leaks costs between $100 and $2,000. The charges can be higher, depending on the severity or source of the oil leak, the type of vehicle, and labor costs.
Here are the average estimated repair costs for a car leaking oil, excluding labor:
- Replacing oil filter cap: $10-$50
- Replacing an oil drain plug gasket: $35-$45
- New engine oil filter: $30-$70
- New valve cover gasket: $240-$290
- Fixing an oil pan: $100-$500
3. What Are the Other Types of Fluid Leaks?
Besides engine oil leaks, here are four other types of fluid leaks you should know about:
- Brake fluid leak: A brake fluid leak can reduce your braking power or cause complete brake failure. It’s easily identifiable with its yellowish puddles and is mainly caused by a faulty brake line or worn-out brake pads.
- Coolant or antifreeze leak: When your car has a coolant leak, it may take longer to warm up. You may also see steam coming out of the hood while driving or after you stop.
- Power steering fluid leak: The consequences of a power steering fluid leak are as severe as a brake fluid leak. You’ll notice a hissing sound under your vehicle’s hood, and your steering might feel heavier.
- Transmission fluid leak: If you notice the smell of burnt oil or have difficulty switching gears you may have a transmission fluid leak. A faulty oil seal, hose, or head gasket could cause this leak.
4. Can I Drive With an Engine Oil Leak?
Avoid driving if you have severe oil leakage or when your oil levels are below the minimum marker.
If you keep the engine running despite low engine oil levels, it will overheat and you could face severe engine damage.
In case of an emergency, you can continue to drive with small leaks, provided the oil levels are good. However, get the leak fixed ASAP. Also, consider carrying extra oil for emergencies in case you need to top up.
Ensure Leak-Free Engines with AutoNation Mobile Service
While oil leaks may not pose immediate concerns, they can be catastrophic if neglected.
Your best option is to diagnose and fix the issue with the help of pro mechanics at AutoNation Mobile Service.
We’re a mobile auto repair service that you can easily book online. You’ll also get upfront pricing and a 12-month, 12,000-mile warranty on new inventory.
Get in touch with us today for an engine oil leak, engine repair, brake repair, or any other services.