What Causes One Cylinder to Have No Compression and How to Fix It

The cylinder in your car is an important component that plays an important role in the combustion process in the engine compartment; as a result, it drives the engine and allows it to function effectively.

If one of your cylinders has no compression, you may have a difficult time operating your car's engine smoothly because it can misfire, among other symptoms.

A misfire in the engine can lead to an emissions test failure on your MOT. It is recommended to check MOT expiry date and have this issue resolved by your local mechanic before total engine failure.

As a result, you should be on the lookout for a blown head gasket or any other condition that might result in no compression in any of your car's cylinders, as well as the best approach to resolve the problem. The next sections of this post go through those topics in depth.

What Causes One Cylinder to Have No Compression?

The following are some possible reasons of no compression in one of your vehicle's cylinders:

Dropped valve -

Two metal valve keepers, each the size of a half-moon, are responsible for locking the valve into the valve retainer and retaining it in place. If one of these valve keepers is defective, it may leap out of the retainer, allowing the valve to descend (drop) into the cylinder and make contact with the piston.

Valve seat drop -

Some cylinder heads are made of aluminium, which expands at a different rate than the metal valve seat. Because of the difference in size between the cylinder heads and the metal valve seats, the seat may fall out of the head. Because air has escaped into the valve's port, there will be no further compression in the cylinder if this happens. Go online and complete a MOT history check to see if the above two have been a culprit in the past MOT tests causing it to fail.

Piston damage -

Another reason your car may have no compression in one cylinder is if the piston rings are damaged or worn out. Excessive heat from the combustion chamber of a vehicle can harm the pistons. The piston will look to be melted or have a hole burned through the top once it has been scorched. This issue is generally caused by pre-ignition or detonation. 

Broken valve -

The head of the valve is intended to seal against the valve seat, but it's broken. If the valve is damaged, the head of the valve may no longer line with the stem, causing it to fall into the cylinder. When the valve head enters the cylinder, the compression will inevitably seep out of that cylinder, inflicting significant damage to the cylinder head and piston.

Valve spring that has broken -

When the camshaft opens the exhaust and intake valves, the valve spring is supposed to shut them. The valve spring is prone to breaking with the passage of time; if this occurs, the valve will inevitably remain open, resulting in compression leakage. Meanwhile, if none of the cylinders have compression, you may have a broken timing belt or chain. The timing belt in your vehicle maintains the camshaft and crankshaft in sync.

The camshaft will no longer be able to function properly if the timing belt breaks and the inability of the camshaft to spin will change the engine compression in all cylinders. A damaged camshaft might also result in no compression in all of the cylinders of the engine. As a result, if your timing chain is damaged, seek out a professional to replace it. Check MOT history online any relevant service paperwork to see when the timing belt or timing chain was last replaced.

What Happens If One of the Cylinders Fails?

If one of your vehicle's engine cylinders is faulty, you'll notice the following symptoms:

Loss of power -

If one of the components that allows your vehicle's engine to function effectively goes faulty, you'll notice recurring engine misfires, knocking, and a proportional loss of engine power. If one of the four cylinders in your vehicle's engine misfires, you might lose up to 25% of the engine's power.

Defective fuel consumption -

If one of your car's cylinders has defective fuel consumption, you'll almost certainly notice it. Because the cylinders contribute to power the engine, if one fails, the workload of the others will be affected to compensate for the loss of power the engine experiences as a result of the cylinder failure. Since a result of the additional burden taken on by the other cylinders, the car's fuel efficiency suffers, as more fuel is required to power the engine.

Vibrations -

If your car shakes or vibrates when idling, one of the cylinders is probably broken. When one of your cylinders fails, your automobile will idle at a slower pace and shake erratically while the engine is operating. Whether you are experiencing any of these symptoms, it is important to inspect your vehicle to see if you have one failing cylinder. If this is the case, you should contact a skilled car technician as soon as possible to get the problem resolved before it worsens. Go through the MOT history and see if there is a pattern of failures in previous MOT tests relevant to the same issue.

How Do You Fix A Cylinder With No Compression?

If you're wondering how to repair no compression in one cylinder, here's a solution that will help you address the problem.

To begin, use a compression gauge to determine whether one of the cylinders has no compression. The test will take around 40 to 45 minutes; thus, make sure you have enough time to complete it.

After determining that one of the cylinders has no compression, inspect the cylinder, gasket, valves, and piston to see if any of these components are cracked or damaged. Please replace any broken components that you find.

How Do You Know If A Cylinder Is Dead?

The information below will assist you in determining whether or not you have a dead cylinder and, if so, how to fix it:

Check your car's spark plugs -

First and foremost, detach each spark plug and inspect the insulator. If you find that they are covered in thick deposits, you may have a problem since the spark cannot reach the plugs because of the thick material. After that, examine the condition of the spark plug insulator from the outside. If you discover micro-cracks, you'll have a problem to solve since the spark from the plugs can escape via these micro-cracks. Make an effort to check the inner insulator, which is located where it is screwed into the cylinder's head. Examine the outer insulator on which the armature wire's cap is mounted.

Check the high voltage wires -

Due to a severe working situation, your car's high voltage wires may become loose, resulting in cylinder failure. Microcracks can also occur as a result of inadequate labour. High discharge can also rupture high voltage wires, resulting in a trail of soot. This might cause the spark from the plugs to be feeble, preventing the cylinder from working. Please replace the faulty wires to resolve this issue.

Inspect the ignition coils -

Vehicles that utilise individual coils or ignition modules for each spark plug may need you to inspect the ignition coils since failure might result in a dead cylinder. If you notice any irregularities in the engine's performance, you may need to remove the spark plug caps one by one to see if there is a spark between the components.

Frequently Asked Questions (FAQ’s)

Is it possible to drive with only one cylinder compressed?

Yes, you may be able to drive with one cylinder without compression but, your car's engine will suffer from issues such as misfiring. Even if you manage to start and drive your automobile with no compression in one cylinder, your car's engine will not function effectively in the end.

It is preferable to have the problem addressed by an auto technician rather than driving with no compression in one cylinder. It would relieve you of a great deal of anxiety and frustration.

Is it possible to revive a cylinder that has stopped working?

Yes, a dead cylinder may be rectified by inspecting and correcting any problematic component that is one of the causes of a dead cylinder. To diagnose a dead cylinder, use a compression gauge to check for any cylinders with no compression.

Because the procedure takes around 45 minutes, you'll need some spare time to complete it. If you don't have a compression gauge, please take your car to an auto repair to get it checked.

If you find a dead cylinder, inspect the cylinder, valves, gasket, and piston to see if any of the components are broken. Once you've figured out which broken parts are to blame, please replace them.

Will a low-compression engine work?

The degree of low compression within the cylinders determines this. The engine may operate, but not efficiently, if only one cylinder has a low compression problem. As a result, driving in one cylinder with low compression is conceivable.

Your car, on the other hand, may not start at all if all of the cylinders have low compression. You'll need to address the issue before your car can start and function properly in this situation.


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