Updated at: 27-07-2023 - By: Lucas

It is common for engine valves to become ineffective at establishing a tight seal between the seat and the valve when they are burned. Exhaust valves exposed to hot engine fumes and parts suffer damage as a result of the burnt valve condition.

The intake valves can also be affected by a burnt valve situation, but this is not always the case. Exhaust gases can leak beyond the sealing of a burnt valve because of a worn-out gap along the margins of the valve.

In addition, the hot engine gases expose the valves to excessive heat, resulting in valve wear. What else can cause valves to catch fire? Burnt valves can be caused by a variety of factors.

  • lean running of the engine
  • a prolonged LPG kit fitting that causes fewer valves lubrication, 
  • and insufficient cooling causing the engine to overheat. 

Common causes of burnt valves

Common Causes Of Burnt Valves

1. How lean running of the engine causes burn valves

Most car engines run lean when the ratio of air to gasoline, or the fuel air mixture, is too low. It’s important to keep in mind that more air and less fuel will enter the engine’s ignition chamber when there is a lot of mixing going on.

In most circumstances, an engine that is running lean indicates a number of serious issues with the vehicle. Fuel injector failures or damage, filthy MAF sensors, and defective oxygen sensors are the most prevalent causes of an engine running low.

It is known that lean mixes burn at a higher temperature than normal air and fuel mixtures. Since the combustion chamber is so close to the engine’s exhaust valves, these parts suffer from extreme heat.

The exhaust valves are considered burned out if they lack a valve guide. A burnt valve is thus the result of an engine running on lean mixtures.

2. How a prolonged use of LPG kit fitting causes burnt valves

Prolonged engine life can be achieved by installing LPG systems in vehicles. In order to employ this method, a new ECU, LPG tank, and modifications to the manifold are all used.

The major purpose of the LPG concept is to enable the vehicle to run on either gasoline or diesel. Because it works with more than 100 octanes, LPG fuel conversion keeps the engine from pre-ignitioning or knocking.

The engine parts in this LPG system are exposed to a cleaner burning environment because any computation-related dirt is removed. Cleaning can, however, run all the way up to the lubrication of the exhaust valves. Burnt valves are caused by a lack of lubrication in these valves, as well as excessive heat.

3.How insufficient cooling causing the engine to overheat causes burnt valves

Your car’s engine is built to do the heavy lifting required to run the vehicle’s critical systems. As a result, the engine heats up, and it needs to be cooled down effectively. Lack of enough cooling will cause the engine to become hotter and eventually cause component burns, including the exhaust valves.

When this happens it results in burnt exhaust valves.

Symptoms of A Burned Valve

  • Engine performances go down: The burnt valves may develop holes that leak out all gases; therefore, the engine will have low gas for compression. Where there is less compression in the engine, the engine’s performance lowers.
  • Causes of misfiring: This results due to the engine cylinder failing to discharge efficiently.
  • Difficulties when starting the car: All parts should play their role correctly for the vehicle to function effectively. If the car has a burnt valve, it will experience difficulties when starting.

Can you drive with a burnt valve?

Common Causes Of Burnt Valves-3

It is possible to drive an automobile that has a charred valve, but doing so will cause greater harm to the vehicle’s internal components. Continuing to drive with the valves burned will result in engine damage. In this case, the best course of action is to avoid driving your car while it has damaged valves and instead wait for them to be repaired or replaced.

An engine misfire caused by burned valves can wreck havoc on the catalytic converter. Damage to a catalytic converter can cause it to disintegrate from the inside out. As a result, the exhaust will eventually become blocked, resulting in even more power loss and difficulty maneuvering the vehicle.

As a result, drivers should either fix or stop using vehicles that have burnt valves.

How long can I drive on a burnt valve?

However, while there is no definitive answer to this question, you should only utilize a burnt valve in an emergency or for short periods of time. Longer distances will result in greater damage and, therefore, greater costs. Repairs will be more expensive, for example, if the charred valve fails.

As a result, while it is possible to drive on a burnt valve for short distances, it is not recommended. Allow the drive to be an emergency only, such as a trip to the mechanic’s. Otherwise, before you go behind the wheel, think about whether or not to replace a damaged valve.

Can an exhaust leak cause a burnt valve?

Yes, exhaust leaks are the principal cause of valve burns. This can lead to a charred valve if the valve isn’t sealing properly An exhaust leak is caused by low back pressure in the system, allowing the unburnt one to move past the valve.

Because of this, the seal between the valve seat and the valve is inefficient. In most cases, burnt valves occur when the valve material is damaged by high temperatures, preventing it from sealing properly.

Can a burnt valve be fixed?

Depending on the severity of the burning, a competent technician may be able to repair a burnt valve. A damaged valve can’t be repaired because it’s no longer functional.

The damaged conditioned components or new ones can be replaced by removing the head cylinder and replacing the damaged charred valve valves that are located there. In the end, the degree of damage dictates whether or not it can be repaired or replaced. There is a difference between minor burns that can be fixed and serious burns that necessitate a whole new device.

How much does it cost to replace a valve?

Even the pieces of an automobile are pricey since they are an expensive investment. Your mechanic shop and any other parts that may be damaged effect the repair prices for a burnt valve. Service and resources are included in repair costs.

Generally, the cost for the required repair resources ranges from around $25 to $60. Valves can be adjusted for between $250 and $350. Depending on where you go, paying the technician can cost anything from $200 to $300.

As a result, replacing a burnt valve is expected to cost around $2000. According to your vehicle, taxes, and supplies needed to reinstall a new valve are all factors in determining your total cost for this service.


Several factors, including normal wear and tear, can cause valves to overheat and catch fire. There may be cylinder misfires and exhaust smoke if the valve is burned. While you can fix this, you can only do so for minor damages, but major ones only need a repair.

It is, however, essential to have a repair done, as driving a car with a burnt engine can cause a lot of damage.