Symptoms, Treatments, And Cures For Oil on Spark Plugs

Symptoms, treatments, and cures for oil on spark plugs

Spark plugs and oil play important roles in a car’s engine’s operation and smooth running. The two, however, should never come into contact but they sometimes do.

This introduces a serious problem that could cause irreversible damage to engine parts. If caught early, the problem can be easily fixed with no damage to the engine or any of its parts.

Function of Spark Plugs

A spark plug is a small but crucial electrical device fitted into the cylinder head of an internal combustion engine. Spark plugs have two main functions:

Starting your car is made possible by the spark that ignites the air/fuel mixture in the combustion chamber. The engine’s pistons are set in motion so your car gets powered up, and a smooth air/fuel mixture burn is maintained. Spark plugs can be compared to the strike of a matchstick, which starts burning fuel.

Heat dissipation: Another primary function of spark plugs is to remove heat from the combustion chamber. If the plug’s firing end gets too hot, this could cause pre-ignition.

It serves as a heat exchanger, pulling thermal energy out of the combustion chamber towards the engine’s cooling system. A spark plug’s heat range refers to its ability to dissipate heat from the firing tip. Different spark plugs have varying heat ranges. Differences in heat range lie in a spark plug’s ability to remove heat between 70° C to 100°C.

How do I Fix Oil on Spark Plugs?

Why is there oil on my spark plugs? This is a common question simply because oil leaks into the spark plug wells is quite common. This issue involves spark plugs and oil. We know why spark plugs are important. Oil lubricates moving parts in the engine to reduce friction.

Moving parts generate a tremendous amount of heat and the oil also helps to dissipate it. Oil is distributed around the engine using an oil pump. It first flows through an oil filter then goes through the engine’s oil passages and through pistons, springs, rings and valve stems.

Needless to say, oil should not get onto spark plugs but sometimes it does. When this happens it means there is an oil leak somewhere. Here are some likely reasons behind such an oil leak.

Leaking Valve Cover Gaskets: The valve cover gasket is a metal part on top of the engine, which keeps it sealed to prevent oil leakage. Considering the high temperatures in the engine when the car is moving, it is not surprising that valve cover gaskets get worn out over time. It typically starts by cracking and later shatters. When this happens oil leaks through it.
Worn valve guides: The purpose of valve guides is to manage intake of air into the engine. They secure the valves when the engine is in operation. Like many other parts of the engine, valve guides get worn after continued use. When they do oil leaks onto the spark plugs.
Worn O-Ring Seals: O-ring seals are positioned right under the spark plug wells. When these seals get worn out or damaged, oil easily leaks through and makes its way into the spark plug wells.
Faulty Piston: If the piston is exposed to too much heat, it cracks. When it does, it lets oil leak onto the spark plugs. Aside from leaking oil, a faulty piston also causes knocking and rattling sounds and weakened engine performance.

What Happens If Oil Gets On Spark Plugs?

Even if you are not a professional mechanic, certain signs will point towards an oil leak into spark plug wells.

Blue exhaust smoke. This kind of smoke is produced when oil leaks, mixes then burns with fuel.
Misfiring. This is felt as a sudden jerk when the engine is running. In this case, it happens when a layer of oil has coated the spark plug.
Backfiring. When oil gets into spark plug wells, fuel particles in the combustion chamber don’t burn as they should. They then enter the exhaust pipe highly charged. The energy is released as mini explosions.

How to Fix the Engine Oil Leakage to Spark Plugs

When you have oil leaking into your spark plug wells, a leaking valve cover gasket or a worn O-ring seal most likely causes it. You can fix both yourself.

As a preliminary caution, make sure the ignition is off. Also disable the battery by detaching the negative terminal.

Remove valve covers: Remove all the cover bolts and pull it out. If the cover has adhered to the head as often happens, use a rubber mallet to pull it out. Avoid using a metal tool like a screw driver because this may cause permanent damage to the cylinder head.
Remove the worn gasket and O-ring seal: If it was installed using silicone, it may not come off easily but will come off with some effort. Discard the two worn out parts.
Clean out the head and valve cover surface: Use plastic tools to clean away any traces of the old gasket that may have been left. Use a degreaser to clean both the valve cover and cylinder head.
Install new gasket: Some engines require use of silicone when installing new gaskets. Check the engine OEM literature to confirm the exact recommendation for yours.

What Causes Oil on Spark Plug Threads?

Oil on spark plugs is a fairly common problem especially in older cars. In newer cars, it is often seen in cars driven with a heavy right foot. Although there are several possible causes of an oil leak onto spark plug threads, they are all as a result of wear and tear.

The best way to avoid this problem in the first place is to inspect your car regularly so you can catch any worn parts before they begin to cause leakages. If you suspect that oil is leaking onto your spark plugs, remove all the plugs, wipe them using a clean rug then put them back into the wells and remove them again. It is possible for an oil leak to affect some and not all spark plugs.

Damaged Piston: Excessive heat can cause cracks or holes to form on pistons. This makes it vulnerable to oil leaks which inevitably find their way onto spark plugs. A cracked piston should not be repaired. It can only be replaced.
Leaking valve cover gasket: The valve cover’s function is to prevent oil leakage from the engine. A gasket is placed between the cover and the engine to keep the cover tightly fixed. High temperatures in the engine sometimes cause damage to gaskets making them brittle.
Even without excessive heat, gaskets get worn over time like any other engine part. A brittle or worn gasket cannot seal effectively so oil leaks onto the spark plugs.
Old O-ring seals: O-rings are situated below the spark plugs and function similarly to gaskets. They are supposed to seal the opening and prevent oil circulated in the system from leaking onto spark plugs. When these rings are damaged or worn out, oil leaks.

Effects of Oil Leaks into Spark Plug threads

Your car’s not starting because of oil leaks on plugs. It would be wrong to tell you not to worry because you should. The only peace you could have is knowing that failure to start the car is typical of an oil leak into the spark plug wells.

We know that spark plugs provide an electrical spark that starts the combustion of the air and fuel mixture. If there is a small amount of oil in the plugs, you may be able to start the car but experience rough idling and surging.

This means the electrical current needed to start the car is transmitted and the spark created, but the combustion process is not happening as it should. If the firing tip is coated with oil, the car won’t start.

Some other telltale signs of an oil leak onto spark plugs include:

Blue smoke from the exhaust pipe: Blue smoke is always a sign of burning oil. In this case it tells you that some oil has leaked into the combustion chamber and is being burned along with the air and fuel mixture.
Engine backfiring: Backfiring happens when unburned fuel finds its way into the exhaust manifold. If oil is blocking the plugs from causing combustion, this could happen. The manifold is hot enough to ignite fuel outside of the combustion chamber and the ignition happens in what seems like a mini explosion.
Misfiring: This can be described as hesitation in the engine when power is demanded from it. It happens when combustion fails to occur in the chamber. It could be caused by a number of failures. Lack of a spark from the plug caused by an oil leak is one of them.

Can Oil Ruin Spark Plug Wires?

Spark plug wires serve to deliver thousands of volts to the spark plugs. To be able to convey such high voltage, they must be covered in thick insulation so that the high voltage doesn’t jump off the wire before it gets to the spark plug. A rubber boot is fitted at each end to protect the metal connectors from corrosion, moisture, oil or any other source of contamination.

When there is an oil leak in the system, these wires may come into contact with hot oil which easily damages them. It could cause a spark plug wire boot to swell and soften and eventually blow a hole in it. A damaged boot could result in a short against the engine block and could even let water into the spark plug well.

Why the Oil Light Comes On and Off When Driving

Why does your car’s oil light come on? It could be caused by one of four reasons, none of them good. These are:

Low oil level
Low oil pressure
Faulty oil pump
Faulty oil pressure sensor

Is An Illuminated Oil Light An Emergency?

It is true that you should have your car checked as soon as you notice the oil light. The urgency depends on the color of the light. Most modern cars have two different lights relating to the oil system. The first is an orange warning light which simply reminds you that your oil levels are running low so you will need to add some soon. When the light is orange it is not considered an emergency because oil levels are still within safe levels. When the light is red, it means oil levels have dropped to unsafe levels and you need to address the problem immediately.

What to Do When the Red Oil Light Comes On

Pull Over: As soon as you notice the red oil light on your dashboard, pull over immediately. If you notice it while driving at high speed, slow down gradually and slowly pull over. It is important to stop immediately because you may be completely out of engine oil and this can cause the car to stop suddenly as a result of engine failure.
Turn off the engine to prevent any damage to the engine.
Check oil levels: Check how low oil levels are by using the dipstick. Remove the dip stick, wipe it clean and then dip it back in. When you take it out again you will be able to see just how much oil is in there. If it is dry or has very little oil on it, don’t attempt to drive the car any further. Call a tow truck to tow the car to the nearest repair shop.

Why the Oil Light Goes On And Off

When a red oil light appears on your dashboard, it pushes a panic button in your mind and you know you have to get to the mechanic urgently. This way you are likely to avoid any potential damage to the engine because the problem is addressed immediately. When the oil light comes on and off at random intervals, you may be tempted to ignore it. You hope whatever the problem was has resolved itself and drive on, only for it to come on again several minutes later. Sometimes the light just flickers continuously and you can’t figure out why.

Oil light flickering while idle

If the oil light flickers while the car is stationary, your first suspicion should be that you have a faulty oil sensor. The oil pressure could also be too low. There should be at least 5 PSI when the car is not in motion. If it is any lower than this the light will flicker. If the flickering stops and the light goes off when the car is in motion then this is most likely to be the problem.

Oil light flickering when driving

If the oil light comes on and off when driving, it probably means the oil levels are too low. Pull over and add some engine oil. The light should go off immediately. If the flickering persists after adding oil, then the most likely problem is worn out engine bearings. When bearings are worn out, the pump squirts oil out of its container causing oil levels to drop drastically.

How Often Should You Change Your Oil?

There is nothing cast in stone when it comes to ideal intervals at which oil changes should be done. It depends on the age and make of the car, the type of engine oil, and your typical driving habits. Even then, you will usually find some discrepancies between intervals your mechanic recommends and those indicated in the car manual.

According to Ford Motor Company, if you have typical driving habits and your car is less than ten years old, your oil should be changed every 7,500 miles or every six months. Whichever comes first.

Typical drivers with cars older than 10 should change the oil every 5,000 miles or every 6 months. Whichever comes first. Non-typical driving refers to frequent off-road diving, transporting heavy loads, towing, and driving long distances at low speeds. In this case, oil changes should be done every 5,000 miles for cars less than ten years old and every 3,000 miles for cars older than that.

Why Is My Oil Light On if it’s Full of Oil?

We all appreciate the importance of oil in the engine but few of us understand the oil circuit. Oil supply begins in the oil pan. A pump is used to suck it up and distribute it to passages in the block. It is then directed to the camshaft bearings, valve shafts, crankshaft bearings, and other moving parts of the system. This makes the oil pump a critical part of the circuit, without which the circuit cannot be completed.

Why the oil light is on when you have just changed my oil is a fairly common problem among drivers. If an oil light remains on even after an oil change, the problem is that oil pressure and not oil level is low. A low oil pressure alert could be as a result of one of these problems.

Wrong Oil Level: You could get a low oil pressure alert due to too much oil. The sensor cannot detect oil pressure correctly because it reads it as an ‘out-of-range’ pressure level. Use the dip stick to check the oil level. If it is above the line indicated on the dipstick it is too much. Remove a small amount until it gets to the required level.
Faulty Oil Pressure Sensor: If you are sure the oil is clean and does not exceed acceptable levels the sensor could be the problem. Confirm this by using a test gauge to measure the pressure. If it is alright the sensor and circuit which operates the light is faulty. This sensor is attached to the engine and has a probe which goes into the oil passage. When dirt gets into the probe the sensor is triggered to switch on the light even when oil pressure level is normal. A faulty sensor should not be a cause for worry. It is quite easy to replace and is inexpensive.
Unlubricated Oil Filter: Oil filters should always be lubricated before installation. If this is not done, oil pressure could drop. The engine requires pressure of at least 5 pounds per inch (PSI.) At this point it is dangerous to rev the engine. Instead remove the spark plugs and run the starter. When pressure is regained in the system, reinstall the plugs and run the engine as usual.
Dirty Oil: If you don’t change the oil when it is due for changing, dirt or sludge builds up in the engine. These deposits don’t clear out even after changing the oil. They can cause abnormal oil pressure, which makes the system give a low oil pressure alert.

How to Reset the Oil Light After Changing Oil

After a regular oil change, you or your mechanic will need to reset the oil light. This essentially sets the system’s mile count back to zero. After this it begins a fresh count of the number of miles driven before the engine is due for another oil change and the oil light comes on again.

Different car models require different processes to reset the oil light though the procedure is generally the same for most cars.

Resetting Procedures

Always ensure the repair technician has fully addressed the problem which caused the light to come on before you reset the light. Here are few ways to go about it.

Use a scan tool

Connect the scan tool to the OBD- II port, usually under the steering wheel. Turn on the ignition and leave it in ‘On’ position. Don’t start the car. Turn off all the car’s accessories like the radio and heater then press the ‘Read’ button on the scan tool.

This allows you to read all the fault codes recorded in the system. They will be arranged in the order they were recorded. Write them down and decode them to ensure you have done all necessary repairs. Keep them safe for future reference.

Repair technicians can benefit from a clear history of past mechanical problems in a car. Once you are sure you have repaired all the problems indicated in the codes, you can erase them by pressing the ‘Erase’ button on the scan tool.

The check engine light will go off if all fault codes are cleared. Some scan tools have an automatic ‘Clear’ option or a ‘Yes’ button instead of an ‘erase’ button.

Turning ignition on and off

Put the key in the ignition and turn it on then off. Repeat this 3 or four times with a few seconds in between each step. After this, drive the car for a few minutes and check if the check engine light goes off. If this doesn’t work, try disconnecting the battery.

Battery disconnection

Using battery disconnection to reset the light is also called a ‘hard reset.’ Make sure the engine is off before touching any of the battery terminals. Use a wrench to remove the negative terminal clamp.

This cuts energy flow from the battery to all components though some electricity may still be left in the system. To deplete it completely, hold down the horn for 30 seconds.

You could also try to turn on the lights. The horn will not make a sound and the lights won’t come on but simply attempting to turn them on depletes any energy left in the capacitor.

Wait 15 to 20 minutes then reconnect the battery. This clears all error codes and resets the check engine light.

Will My Check Engine Light Reset Itself?

The check engine light on the dashboard of your car comes on when there is something wrong in the system. This is how it communicates with you to tell you to take the car to a repair shop and have it checked by a technician. What causes the light to come on?

The car’s internal computer detects a problem. It then records a code, also called a diagnostic trouble code (DTC) corresponding to the problem in the engine. The technician easily identifies the problem causing the check engine light to come on by reading the DTC using a scan tool.

Once the repair technician identifies the problem and rectifies it, the light should go off. Every car has specific criteria used to clear DTC’s from the system. In most cars, the light resets itself after 10 to 20 successful cycles. One cycle is measured when the car is cold, the ignition is started and it runs until it gets to operating temperature.

However the light does not always reset itself. Some cars may have you driving for days or weeks with the check engine light on, even after the problem which caused it has been resolved. If you are like many drivers it will irritate you to drive around with the check engine light on long after the problem has been repaired.

It is also somewhat dangerous to have it on for so long after the repair has been done because you may wrongly assume the light is on from the last repair when there is another mechanical problem requiring attention.

If it doesn’t go off immediately, leave it for a couple of days. Some cars just require you to drive about 15 miles for it to reset itself.

What Is Freeze Frame Data?

Freeze frame is an element of modern vehicle’s self-diagnostic systems in which specific engine operating conditions are recorded at the moment the check engine light goes on. The resulting data is known as freeze frame data. This data is then be used to diagnose the problem and resolve it.

It is from the results of all these tests and checks that he can pick out exactly what is amiss, make a diagnosis and treat you. A car’s freeze frame data is like your test results during illness. They give the repair technician a list of parameters as they stood at the time the fault was detected.

Conclusion

Having oil in your spark plug wells is not one of those problems you notice and wait until it is convenient to fix it. It is actually a very serious problem which should be rectified immediately it is noticed.

It can cause damage to the engine such as warped pistons and valves. If left unchecked for some time, it could cause an engine fire if the plugs ignite the oil. If you don’t know how to fix oil on spark plugs, take your car to a professional mechanic immediately.

FAQs

What is the cause of oil on bottom of spark plugs?

The major cause for this is that your spark plugs are sitting at a pool of oil that is as a result of bad spark plug tube seals. It’s not the plugs themselves leaking oil but the place where they are seated. One of the first symptoms of this is that the oil is found on the tip of the spark plugs. If you are going to fix this, you will need to change the tube seals by starting with the valve cover. There also some spark plug stop oil seals products in the market that prevents this problem. If this does not work you will have to deal with a mechanic.

Can low gas cause the check engine light to come on?

The check engine light can be triggered by a variety of malfunctions in the system. One of them is excessively high temperatures which are interpreted as overheating. Can an almost empty gas tank cause the check engine light to come on? Yes. It can.

Here is why.

The fuel pump in the gas tank relies on fuel to keep it cool. It should always be submerged in it. When you constantly run your car on a low tank the fuel pump is not submerged so it could overheat and trigger the check engine light to come on.

The best way to deal with this is to avoid letting your fuel tank go below quarter tank. Running the car with very small amounts of fuel also causes low fuel pressure which could also cause the light to illuminate.