Your car needs a lot of fluids to run efficiently. While each fluid is crucial in its sense, oil, coolant, and fuel are perhaps the most important. It would help if you were worried any time you see an unaccounted pool of these fluids under your car after parking for a while.
We recently did a post focusing on dropping coolant levels. Today, we are going to focus on oil levels.
Just like the case with dropping coolant levels, your car will still crank and move for a while after developing an oil leak. However, keeping on driving could lead to catastrophic failure.
To start, we are going to look at the most common signs that you’re losing oil. If you’re already sure, you can skip to the section on why this could be happening.
Signs That Your Car is Leaking Engine Oil
While the signs we will explore are easy to note, you will have to keenly observe your car and its surroundings before driving off. Be on the lookout for:
Dropping Oil Levels in Your Sump
This is the primary way to check and prove that you are losing oil is a steady drop each time you check your oil levels.
How to Check Engine Oil Levels
There’s more to checking engine oil level than just pulling out the oil dipstick and pondering over it. Here is a quick step by step guide on how to check your oil level.
- Park the car on some level ground. Any inclination could give you wrong oil level readings
- Switch off your engine and let the vehicle sit for around 10 minutes. This gives the oil time to return to the oil sump. (check this for more on whether you should check oil levels on a hot or cold engine)
- Identify the location of your dipstick and pull it out. Wipe it clean with a dry lint-free rag
- Insert the dipstick back into its pipe fully. If it’s stuck on the way, twist it around. The pip is curved, and the dipstick assumes the curve naturally if inserted the correct way
- Let the dipstick lie for approximately 15 seconds before slowly pulling it out again
- Look at the level of oil stain on the dipstick. It should be at the FULL mark (mostly a hole) or between the FULL mark and ADD mark
- Also, check the color of the oil. A dark, almost black oil might mean its time to change it
There is nothing to worry about if your oil is at the FULL mark. If it’s below this but still above the ADD/LOW mark, you can keep monitoring it daily to see if you’re still losing oil at an alarming rate.
If it is low, you can top up your oil and monitor your car to see if you lose more oil in a short period.
Is It Normal for Oil Levels to Decrease?
Yes. It’s normal for oil levels to decrease. Most engines will burn some oil over time. Losing a quart of oil over 1500 miles of driving is acceptable. That’s why car owners are advised to check oil levels and top up as necessary.
However, if you are losing more than this or plain losing oil without driving the car, chances are you have a leak somewhere in the system.
Dark Puddles Under Your Car After Parking for a While
A dark fluid puddle under your car in the driveway is the first sign that you are losing oil fast. It could be dark black, dark brown or yellowish depending on the condition of your oil.
Note that you can only use this technique if you first confirmed there wasn’t a pool when you packed your car.
An oil leak pool often forms towards the front of the car under the engine. You can touch the pool and feel the texture or viscosity by rubbing it between your fingers. It should be slick as oil.
Sometimes, you could confuse normal water from your car’s drainage outlet with an oil leak. This check helps you ascertain that the pool of liquid you see under your car is oil – not water or coolant.
Blue Smoke From Your Exhaust
Modern cars aren’t supposed to produce any noticeable smoke at the tailpipe unless they are diesel at times.
However, if your engine is burning oil, you will see a whiff of blue smoke from your tailpipe.
The leak could be due to several faults within the engine. These include:
- Leaky valve seals
- Damaged piston rings
- Worn cylinder walls
You will need to note when the smoke intensity rises to narrow down the problem. For instance, if you get more smoke as you accelerate/rev up, then it could be damaged piston rings—more blue smoke when decelerating means damaged cylinder head valve guides.
Either way, take your car to a mechanic as soon as you see dropping oil levels and blue smoke at the exhaust pipe.
A Dashboard Oil Light
Most modern cars have sensors monitoring oil pressure and levels. Any abnormality is relayed to you via a dashboard oil light. Even though an Oil Light doesn’t always mean you have a leak, you should have it investigated immediately.
An Overheating Engine
An overheating engine doesn’t always mean you have cooling system issues. Oil plays a crucial role in keeping your engine temperatures low.
By lubricating your pistons and their housing, it reduces frictional heat. Moreover, oil could circulate heat around, making it easier for coolant to whisk it away from the engine.
Lowered oil levels impair this ability making your engine more susceptible to overheating.
A Burning Oil Smell
Sometimes, your oil could be leaking off your valve cover or the timing chain gasket. If this is the case, the oil will leak onto hop parts of the engine, making it burn and smell.
Burning oil produces a thick, bitter smell. You should also get a frying bacon sound under the hood if you pop it while the engine is still hot. You have to switch off the engine to hear it.
Fresh Oil Smears Around Your Engine’s Joints
If you miss out on the burning oil smell and sound, you could still note engine bay oil leaks by inspecting the engine closely.
Pay attention to your valve gasket, the point where your timing chain cover meets with your valve gasket and any other joints in your engine.
Running your fingers along these joints could help you identify oil leaks. Fresh oil on your fingers is sign enough.
Also, it would be best if you considered keeping your engine clean so that you can identify any fluid leaks at a glance when you pop your hood.
A Misfire – Sometimes
Sometimes, if you have a leaky valve seal, oil could leak into your spark plugs. Oil will foul your ignition coils and spark plugs leading to a misfire.
Check the condition of your sparkplugs and their sockets when swapping them after a misfire to ensure that they are dry and don’t have oil residue.
What Causes Oil Leakage
Now that we’ve identified for sure that you have an engine oil leak, it’s time to pinpoint different causes of this loss.
A Damaged or Missing Oil Filler Cap
Your oil filler cap isn’t just there for show. It helps keep oil in the car. Since oil circulates under pressure, a missing, loose, or faulty oil filler cap could make your car spit out some oil when it runs.
Ensure that your oil filler cap is in good condition and that it is tightly screwed on. It should be hand tight.
Overflows or Too Much Oil
If you see oil puddles, smears, or a burning oil smell immediately after refilling or swapping your engine oil, chances are you are detecting spills or overflows.
If your Engine Oil light isn’t flashing and your oil levels are still above the MAX level, there should be nothing to worry about.
You can use a rag to clear up the spills (normally around the filler opening). Also, use your dipstick tube to extract excess oil from the system.
Scroll down to the section we did about overfilling engine oil for more insight on this.
A Damaged Oil Filter
Broken or worn-out oil filters could make your car leak oil. If you don’t check it often, chances are it will get clogged or damaged over a couple of thousand miles.
The area around your oil filter should be clean and devoid of oil residue. If you notice this, consider changing your oil filter.
Sometimes, your oil filter might be so loose you could even tighten or screw it out quickly with your hand.
A leak at the oil filter could also happen if its thread were stripped by installing it unaligned to the socket.
A Damaged Oil Drain Plug
The drain plug is the small nut at the bottom of the oil pan that lets you drain the oil when doing a swap. Over time, the plug could wiggle loose, creating an imperfect seal causing a leak.
The oil drain plug could also leak if it has worn out thread or was screwed on misaligned.
You can tell it’s a problem if you see fresh oil around the plug or a pool of oil immediately beneath it.
The good news is it’s easily accessible – well, as long as your car doesn’t have a lot of undercarriage protection sealing off everything.
A Leaking Oil Sump
If your oil drain plug is still intact, you could still lose oil from your sump through tiny fractures or holes. These are common in low slung cars that graze over bumps or pavements when driving.
You could also damage your oil pan when offroading. Be sure to inspect your oil pan whenever you hear your car graze over something as you drive.
Damaged Oil Pan Gasket
The last leak your oil pan could develop is if its gasket is damaged or unseated. Oil pans need some gasket where they join with the bottom side of the engine. This helps them create an oil-proof seal.
Over time, this gasket gets worn out and develops tiny or sometimes massive leaks.
A hit to the oil pan could also dislodge or bent its edges, damaging the gasket’s seal. Luckily, gaskets are cheap and easy to replace.
Remember, you will have to replace your oil any time you work on your oil pan—budget for that too.
Damaged Valve Gaskets
A faulty valve gasket is a common cause of engine oil leaks in older vehicles. This gasket sits between the engine block and the engine head.
As time goes by, the gasket disintegrates and begins to leak. The oil will either leak onto the outside of the engine, burn off, or create a visible smear.
At other times, it will leak into the spark plugs and ignition coils. This will damage them, causing your engine to misfire.
The solution is as simple as replacing the valve gasket. Don’t worry. Valve gasket replacement is less demanding than head gasket replacement.
A Damaged Timing Chain Cover Gasket or Seal
The other gasket that could get worn over time is between your engine block and the timing chain cover. This is only applicable to cars with a timing chain and not a belt.
The timing chain needs oil lubrication. As such, it’s housed in an oil-tight chamber. This chamber shares oil with the engine. If its gaskets are at fault, you will notice some oil on the engine around the gasket.
In most cases, the leak will be at the point where your chain cover meets with the valve gasket. This spot is often big and susceptible to leakages.
Internal Leakages
The last and hardest to troubleshoot causes of oil loss is an internal leak. This is when oil leaks into the combustion chambers and is burnt off with fuel.
A tell-tale sign of this happening is blue smoke coming out of your exhaust pipe.
Internal leaks could be caused by:
- A damaged head gasket
- Faulty cylinder head gasket
- Damaged piston rings
- Worn out cylinder walls
- Damaged Camshaft Seals
This is a common problem in cars with timing belts to synchronize the crankshaft and the camshaft.
Your engine will have some seals at the end of each side of your camshafts to prevent oil from leaking out of the engine.
If these seals are damaged, you will see oil on the rear of the engine just below the valve cover. Your hot engine might also burn this oil, causing the tell-tale burnt oil smell.
Bad Front and Rear Crankshaft Seals
Even though your crankshaft is an internal engine component, it has protruding points that interface with components like flexplates, a balance, and the flywheel.
The crankshaft needs seals to keep oil from seeping out of the engine. A small leak on this will make oil accumulate on the underside of the engine. Big leaks will cause visible oil smears at the front of your engine.
Can You Drive a Car With an Oil Leak?
No. Driving with an oil leak is not safe.
While your car will still move with an oil leak, it is unwise to keep driving and topping up the oil.
Leaking oil damages rubber hoses and seals, leading to more problems. Moreover, if you are losing oil fast, your engine won’t be properly lubricated. Friction will get to it.
Additionally, oil on your engine could be a fire hazard. If heated right, it could catch fire, causing more damage and harm.
How Do You Fix Oil Leaks?
In most cases, fixing an oil seal permanently involves intensive troubleshooting to identify where the oil is leaking from. After this, you will have to replace the damaged component and top up your engine.
This is the right way and yields permanent results. It is also the inevitable way if you are losing oil fast.
However, if you have a small fracture and oil is wasting away gradually (very slowly but faster than the normal loss rate), you can resort to stop leak additives.
The problem with these additives is you have to use them every time you swap your engine oil, and it isn’t guaranteed that they will work.
It doesn’t hurt to try, though.
Can Oil Leaks Fix Themselves, or Do They Get Worse?
Sometimes, very small oil leaks can fix themselves. If you notice a pinhole leak after changing the oil (especially moving from normal to synthetic oil), you might be lucky. However, when this happens, the leak was such small that you didn’t notice it in the first place.
Big noticeable oil leaks often remain or get worse over time – especially if they involved a worn-out gasket.
Is an Oil Leak Expensive to Fix?
The money you spend fixing an oil leak depends on the leak’s location in the first place.
Case in point, changing an oil filter should be cheaper than replacing a valve gasket or dealing with damaged piston rings.
Have a mechanic troubleshoot your leak before thinking about the money. If you are handy, you could narrow down the problem and estimate how much it might cost you to fix the leak.
How Long Can You Drive With an Oil Leak
Normally, I would advise you not to drive with an oil leak. However, you can still drive your car as long as you keep your eye on the oil levels. A few miles to get to a mechanic is OK. You don’t have to tow your car to the repair shop.
However, going on driving as if nothing is wrong is dangerous. You could blow your motor in the process.
What Happens if You Overfill Engine Oil?
If you overfill your engine with oil, the levels on the oil sump get too high. This could be high enough for the crankshaft to contact the oil as it spins. This will aerate the oil, making it frothy. Foamy and bubbly oil doesn’t lubricate your engine well.
Extra oil will also increase the pressure within your engine. This increases the chance of gaskets and seals within your engine to fail cause engine oil leaks.
How Much Oil is Too Much Oil on the Dipstick?
A quick way to tell if you have too much oil is by checking your dipstick. Follow the standard procedure to check your engine oil.
The different level markets on your dipstick mean different things depending on your car. Consult your manual to learn more.
However, the basics are:
- MAX: The maximum acceptable level at any point (after your engine has cooled for around 10 minutes)
- MIN: The minimum acceptable level – especially on a cold engine
Anything between the two levels is acceptable as long as you keep frequently checking to fall below the minimum.
The best practice is to maintain your engine oil level at or very near to the full mark.
If your car has an oil pressure monitoring system, high oil pressure warning could mean that you overfilled the oil.
Other causes of high oil levels when you didn’t overfill include:
- Fuel diluted oil from leakage or blow-by
- Condensed water from combustion (use the sizzle test to confirm)
- Coolant leakage (check for cloudy residue in oil)
- Short-run engines, especially in new imported cars
Check this too: How Do You Fix a Flooded Engine?
How Do I Fix Too Much Oil in My Car?
There are many ways to fix high oil levels. If you are sure you overfilled the car, you can use shortcuts like:
- Siphoning the oil out of the car
- Opening the drain plug a bit so that you can lose some oil and fill it up to the right level
However, if you didn’t top up or change your oil, chances are a leak is increasing the oil level.
If this is the case, you have a problem to fix – and your oil is contaminated. Avoid the shortcut approach. Find and fix the problem and then change your engine oil.
Bottom Line
An oil leak in your car isn’t something you should ignore. Tending to it as soon as possible is better than topping up and hoping that nothing terrible will happen.
If you are not handy, consider taking your car to a mechanic for comprehensive troubleshooting. They will help you identify the possible cause of the leak and fix it before it’s too late.