Will Oil on Spark Plugs Cause Cars Not to Start?

As an Amazon Associate, I earn from qualifying purchases.

Do you face trouble starting your car? It happens for multiple reasons, including seized battery, worn-out connection cable, faulty alternator, etc. Also, there are several factors that prevent starting or moving the car. But will oil on spark plugs cause the car not to start?

The simple answer is yes. When the oil enters the spark plug valve covers or tube galley, there is a chance to short out entire coils and plug wires. As a result, the engine won’t start. And if the engine fails to start, the entire system runs off suddenly.

In addition, as a bonus, engine misfiring, higher oil consumption, and blue smoke from exhaust will happen. In this case, you must know how to deal with it, what causes this issue, and how dangerous it is. If you want all these things in one place, keep reading this article.

Signs Of Oil On Spark Plugs

The car is equipped with many larger to smaller components. Among them, spark plugs are the most critical and comprehensive ones to keep the engine running. However, how do you know if there is oil on the spark plugs? So guys, let’s get to know them in-depth.

Engine Misfiring:

If you notice the engine misfire while driving, check the spark plugs immediately. Engine misfiring occurs for many reasons. But it’s a telltale sign of an oily sparker or oils on the wells.

It happens because contaminated oil on the detonators can’t produce the required ignition as the faulty plugs can’t ignite the air-fuel mixture. As a result, the engine doesn’t get sufficient power, which in turn causes the engine to misfire. 

Blue Color Smoke Coming From The Exhaust

Another understandable sign that tells spark plugs have caught up with oil residue is coming out of blue-colored smoke from the tailpipe or exhaust. When the detonators catch up with oily grime, the oil will burn, and the smell will come out. It also indicates the oil is polluted in one combustion chamber.

Engine Backfiring

Besides misfiring, you’ll probably notice the engine backfiring if there is oil on the spark plugs. It happens when the air-fuel mixture burns the external side of the combustion system.

As a result, oils can’t burn properly and the unburned oil residue causes poor combustion. After that, the mixture of fuel and air forces the unused gas out to the back pipe, which in turn causes the engine to backfire.

Reduced Fuel Economy

This is really unfortunate and frustrating as well to experience poor fuel economy. While there are several reasons behind this issue, oil contamination or oil residue on the sparkers causes this problem widely.

If the spark plugs start to malfunction, it prevents the proper ignition and combustion. Consequently, fuel economy reduces gradually but surely, which in turn increases fuel consumption.

Poor Car Performance

Sparker has a direct link to the engine. Any wrong with this item can lead to significant engine issues. And if the engine faces trouble and doesn’t get enough power to perform, the car won’t move.

Therefore, you experience poor car performance, sometimes, the car does not start. Therefore, there is clearly evidence of oily detonators according to Auto Trends.

Entering The Oil Into The Combustion

After the detonators get wet by oil, you’ll notice the oil entering the combustion unit. It happens because of the worn-out valve stem stamps. When the valve stem seal leaks or is damaged, oil can effortlessly enter the combustion chamber to make inconsistency.

Check Engine Light Illuminates

If the oil is saturated for a long time and plugs start to expose their worst-case scenario, the check engine light will illuminate the dashboard. You need to be hurried enough after noticing it.

Low Engine Oil

Last but not least. A final sign on this listing for wet sparkers is low engine oil. Though there are several problems that occur when this small part gets saturated, you’ll also notice the engine always warning low levels of oil.

In addition to the above symptoms, burning oil smell, engine overheating, etc. are must-focusing signs.

9 Causes Of Oil On Spark Plugs

Will Oil on Spark Plugs Cause Cars Not to Start

Any malfunction in the car’s parts will be harmful to you and your car. This is why you should check and inspect them after every ride or every week at least. If you want to get rid of oil on spark plugs, you should know the reasons why it gets oily over time.

Here is a list of possible causes to figure out why this happened.

1: Worn-out Piston or Piston Seals

The most potential cause for oil on spark plugs and the car not starting is a cracked or damaged piston. It seems mostly in the Otto-cycle engine. When the piston seals leak oil, the oil builds up or accumulates on the plugs. And this way, it covers up with oil and causes serious problems from poor car performance to complete engine failure.

2: Valve Cover Gasket Leakage

A depreciated valve cover gasket is the considerable culprit that allows the oil to drain the bottom of the engine valve cover. It happens when the gasket loses its seal. Consequently, the oil drips from the seal, and the engine loses oil, which results in fuel consumption. Please note, that valve cover leaking is a serious issue that should be taken into account.

3: Valve Guide Malfunction

Valve guides or seals set the intake and exhaust valves of an engine. These guides have protected seals that prevent oil trespass into the combustion chamber. Unfortunately, this guide is prone to damage from time to time that can’t prevent oil from flowing unnecessarily or to the wrong place.

4: O-Ring Seal Leakage

When you notice the sparker’s wells are filled with oil, look at the O-ring seal. It eventually happens to leak the O-ring seal. You can find the o-ring seal surrounding the valve cover gasket.

5: Not Using Recommended Oil

Well, this is considered the most intriguing cause for this happening. Spark plugs tend to get oily because of using the wrong oil in the car. It not only causes the spark plugs to get oily but also reduces lubrication and damages the engine quickly. 

6: Head Gasket Malfunction

Properly aligned or functional head gaskets play a crucial role in making the engine power. But when the head gasket fails to deliver as it should, the engine requires more work done to gain or create better power. The coolant escapes to the plugs, causing deposits to form. Finally, the spark plug head’s fouling occurs and contaminates spark plugs with oil.

7: Cracked or Issues in the Positive Crankcase Ventilation

Cracked or clogged positive crankcase ventilation (PCV) is another warning that the spark plug’s tip has been filled with oil. If the crankcase goes faulty or stuck, you probably experience overpressure in the crankcase. Then, it pressurizes the oil pressing hard into the combustion chamber from ventilation or valve sealings or turbocharger.

8: Too Much Oil

If you insert too much oil into the oil tank and the air-fuel mixture doesn’t organize properly, the oil drips into the gasket. As a result, the head of spark plugs gets oily and wrapped with other contaminants. Never put oil at the maximum level as it spaces excessively in the moving parts, particularly in detonators.

9: Worn-out Turbocharger

A turbocharger comes in handy when compressing a significant amount of air to flow into the engine’s cylinder. But when it goes faulty, it contributes to building oil on the spark plugs and the car not starting.

However, it is pretty common to leak the oil from the turbo inlet compression coatings, the oil goes via the combustion chamber. Then, the oil sticks on the spark plugs and makes an oil coat.

Impact Of Oil On Spark Plugs

Worn out any part like a sparker is a warning sign and it should be handled with a safe hand. Do you know how alarming is it when the oil is saturated on the sparker? If you don’t, scroll down for a better understanding.

Starting Issue

The first thing you may encounter for oil on the spark plugs is foul starting. You won’t be able to start the engine as there is a direct connection between the sparkers and the engine. If the spark plugs can’t produce a spark and ignite the air-fuel mixture, this roughly affects the combustion. As a result, the engine doesn’t get enough oil and power to move.

Rough Running

Suppose, you could start the engine after attempting hard. But you can’t go long mileage or feel rough running. Indeed, the engine sounds rough even if the engine is in an idle position. Any compromised spark plugs can be horrifying and you might hear vibrations.

Worst Impact On The Valves

The valve can be damaged if the sparker gets oily and other deposits. And if the dedicated valve gets leaked, the oil drops rapidly. As a result, the engine leaked oil which caused the engine to fail to function.

Hurt Engine Performance

As mentioned, we all know that the more spark plugs function well the more you receive better performance. But when the oil on spark plugs happens, you end up experiencing some inconvenience in driving your car.

Increased Oil Consumption

Everyone wants better mileage with better fuel efficiency. But unfortunately, it won’t gain if the sparker starts to malfunction. When the oil drips into the cylinder or engine’s head, the plugs are saturated and cause reduced fuel economy.

How To Clean Oil On Spark Plugs

Inspecting and maintaining spark plugs or any other components is a must-do duty for a car owner. If you don’t, you could end up with giant issues next time. Cleaning oil on the spark plugs regularly keeps the part efficient. So here is a solution on how to clean oil spark plugs.

  • First, take a paper towel and pen or marker that is perfectly shaped with spark plugs.
  • Then, wrap around the pen or marker with a paper towel. Keep it right to the same diameter as spark plugs. Otherwise, it cannot enter the spark plug’s head.
  • Right after, lower the lower end of the wrapped pen into the spark plug well to soak up the oil. Remember to do this after the engine is cooled down thoroughly. Force the pen down several times to get most of the oil. 
  • Then, spray a break cleaner down into the spark plug well.
  • After that, apply compressed air to blow it out. You can also use Ultra Duster to remove the oil residue.

Note: There are also some effective methods to clean the oil on the spark plugs. So you can try them too.

Best Practices For Avoiding Oil On Spark Plugs

Now, it is time to know the tips and tricks for avoiding oil on spark plugs. Knowing them is required to keep the system organized and workable. Following are some of the simple processes to keep the plugs oil-free.

Tip 1: Inspect And Replace The Gasket At Regular Intervals

Maintaining your car and each part regularly is the precondition to getting peak performance. The spark plugs seem small but have many funiculitis to keep the engine running. This is why you should inspect this component after every ride and check if there is any oil inside or top head.

Tip 2: Know About Your Car’s Functionality

Without knowing about your car makes you feel disturbed when doing some work. Also, if you have no idea what spark plugs go right to the car, you end up installing the wrong one which can’t perform efficiently. So first understand the car’s functionalities and take action accordingly.

Tip 3: Change The Spark Plug Tube Seal

Spark plugs tube seals play a crucial role in preventing the oil from going into the spark plugs. This way the spark plugs work well. So change the tube seal now and then to get better performance.

Tip 4: Tighten The Spark Plugs

Loosen spark plugs cause poor engine performance, early ignition, detonation, and dead cylinder. Also, it may drip oil into the plugs and make the plug oily.


Spark plugs do a lot from making the engine perform to keeping the engine better for a long time. Though the item is small, you can’t ignore it if you need a better ride. Unfortunately, these components are prone to damage in many ways. Oil on spark plugs is one of them. And for this difficulty, you will face lots of trouble.

However, will oil on spark plugs cause the car not to start? Yes, it resists the car not starting. Luckily, there is a solution to get rid of this issue. This article is arranged with symptoms, causes, difficulties, and solutions regarding oil on spark plugs. Hope you enjoyed the reading and benefited.

Leave a Comment