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What effect does oil on spark plugs have on engine performance?

by Car Service and Repair 4 months ago in list
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Oil on spark plugs symptoms include blue smoke from the exhaust, poor fuel efficiency, and engine misfires. Bad valve cover gaskets, worn spark plug o-rings or valve guides, a damaged head gasket, or a cracked piston ring can all create oil on spark plugs.

Let's use our lighter example to substantially simplify the solution. Assume you're trying to start a campfire, but your lighter is contaminated with engine oil. You'll ignite the campfire eventually, but only after multiple failed attempts. Consider a spark plug for a moment. There will be no ignition or combustion if there is no spark. Fuel will be provided, however, it will not be burned when it exits the cylinder.

What Causes Oil on Spark Plugs?

One of the few components in close touch with the combustion process is the spark plug. In contrast, engine oil should never come into touch with spark plugs. So, how does oil get to the spark plugs of an engine:

1. Bad Valve Cover Gaskets

Cylinder heads are made up of more than just spark plugs. Intake and exhaust valves, valve springs, cam(s), valve guides, and other components may be included depending on the engine configuration (OHV/SOHC/DOHC). Because the majority of those components require lubrication, engine oil is poured all the way from the oil pan to the heads. The valve cover gaskets' job is to keep oil on the cylinder heads and out of the rest of the engine. Valve cover gaskets wear out over time due to the high temperatures involved, enabling oil to escape. In Over Head Valve (OHV) designs, dripping oil can reach spark plugs, resulting in oil on plug situations. During the extra health check on the vehicle, a car technician at a car services in Reading garage will be able to advise whether there is a poor valve cover gasket and what expenses are needed to fix this issue.

2. Degraded Spark Plug O-Ring

The valve cover on the Single Over Head Cam (SOHC/DOHC) and Double Over Head Cam (DOHC) designs features a seal known as the spark plug O-ring. Heat, like the preceding point, tends to deteriorate this seal over time, allowing oil to access the spark plugs. When completing a spark plug replacement during a major car service Reading, the technician should notice if the spark plug O-rings are worn out.

3. Valves Guides That Are Defective or Worn

Excessive wear on the valve guides might also be the source of this problem. The steady up-and-down movement of the valves "pumps" oil into the combustion chamber, causing oil on the spark plugs. Look for competent car services Reading garage and book your car with a qualified mechanic.

4. Broken Piston Compression Rings

This problem can also be caused by a broken compression ring. The oil pan builds up positive pressure as the engine ages and compression begins to decline. If the ring is damaged, that pressure might make its way into the combustion chamber during the compression cycle. Book an appointment with a trained technician at a garage in Reading if you believe you are looking pressure.

5. Faulty Head-Gasket

The oil lubrication system transports pressurised engine oil from the oil pan to the engine's head. Oil might leak into the cooling system and/or the engine cylinder due to a damaged head gasket. Schedule an appointment with a car garage in Reading to diagnose and replace the head gasket as paying out for replacing a leaking head gasket in time will be better than paying for a full engine replacement later if the engine totally fails.

6. Broken Piston Head

A broken piston head is a less probable (but still conceivable) cause of this issue. Positive pressure from the oil pan may readily transfer through the piston to the combustion chamber and onto the spark plug, similar to the previous point.

What are the symptoms of oil on spark plugs?

The most common oil on spark plugs symptoms can include the following:

1. Blue smoke form exhaust

2. Reduced fuel economy

3. Reduced engine performance

4. Possible engine misfires

5. Engine backfires

Gas like smell from exhaust


About the author

Car Service and Repair

Car Services in Reading prides itself on providing great customer service, fair and competitive pricing along with great quality work that leaves you happy with the entire process.

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