How To Tell if Your Car Needs a Valve Adjustment?

The most important part of any car or vehicle is the engine; it’s responsible for the car’s movement by combusting the fuel and generating power. The fuel is combusted in the engine’s cylinders; each cylinder consists of two valves and one piston.

The valves of the cylinder allow the flow of air in and out of the engine cylinder, providing the required air to combust the fuel in the cylinders. If the valves go out of shape, they affect the engine’s performance, and the engine will not work at its maximum efficiency.

How To Tell if Your Car Needs a Valve Adjustment?

You can tell if your valves need an adjustment by listening to your engine’s sound when you start the vehicle. The engine should be making noises like clicking and tapping if its valves are out of shape. Another moment in which you should be listening to the sound of your engine is at power loss.

When you experience any loss of power in the engine, you will notice a clicking or tapping sound in the engine of the vehicle. In addition, you can tell if your car needs a valve adjustment by noticing the idling time of your vehicle. If the vehicle is facing a rough idling time, this can be a sign of bad valves.

Idling time can tell you if the valves need an adjustment because you will notice that the car is having a rough time due to the late opening of the valves, which causes the fuel to choke the car. There are more signs that you can tell from them that valves need adjustment, for example:


Overheating of the engine can be a sign that your valves need to be adjusted; valves are responsible for letting the air in and out of the engine. When the valves are in bad shape, they tend to open and close slower; as a result, this causes the heat not to be dissipated properly.

The improper dissipation of heat over time causes the engine’s heat to rise. And as a result, the engine gets overheated faster than usual, which can affect the performance of the car or damage the engine.

Fuel Overconsumption

Fuel overconsumption can be another sign of out-of-shape valves, and you need to adjust them. If you notice that the fuel is being overconsumed lately, that could be a sign. The reason for this overconsumption is that the exhaust valve, the second valve in the engine cylinder, opens at the wrong time.

The intake valve or the first valve in the engine cylinder is responsible for intaking the air and the fuel and delivering them to the chamber. The exhaust valve should open after the intake valve finishes. However, when the valves need to be adjusted, the exhaust valve opens earlier, which makes the fuel come in and out of the exhaust valve.

Pre-ignition Problems

Pre-ignition problems can also signal that the valves need to be adjusted; these problems occur when the combustion chamber fuel is ignited earlier than the fire of the spark plugs. The clearance of the valve is affected when the valves become out of shape; therefore, the valve causes the engine to heat faster.

This increase in the engine’s heat causes the engine to heat up too much, which makes the engine ignite before the fire of the spark plugs.

Engine Making Noises

As discussed earlier, the noises of the engine can be a sign that valves need to be adjusted; the engine starts to make clapping or clicking noises when you start up the vehicle. The main reason for this problem is that the friction between the engine and the cylinder increases.

This problem should be handled as soon as possible because it can affect the performance of the engine, and you can experience a gradual loss of power over time.

What Happens When Your Valve Needs Adjustment?

Valves can be considered as the lungs of your engine; therefore, when the valves are out of shape or need to be adjusted, the engine is not breathing. As a result, the efficiency of the engine will decrease over time because the engine is not getting enough air.

When the valves need to be adjusted, the exhaust valve in the engine’s engine cylinder opens at the wrong time. So, the fuel from the intake valve will come in and out of the exhaust valve, which means the fuel will leak past the exhaust valve. The leakage of the fuel can cause the engine to fail and get damaged.

Lastly, the engine will not operate at its maximum power, which means it will burn the fuel faster than it should. As a result, the exhaust smoke will also increase.

Can Out of Shape Valves Cause a Misfire?

Valves that need to be adjusted can cause the vehicle to misfire, which happens when one cylinder or more is not operating at maximum efficiency. For example, when the valves are tightly adjusted, this can cause a misfire; if the valves are not properly adjusted, this can cause a misfire.

When the valves are not properly adjusted, this can affect the fuel-air mixture, and as a result, this will affect the performance of the cylinders. This can make one cylinder or more not operate at their full power. 

What Are The Benefits of Adjusting Valves?

  • When you adjust your valves, this can increase back the compression to its normal value because unadjusted valves can affect the compression. The incomplete closure of valves is caused by decreased clearance and can lead to many problems like leaky chambers. The combustion chamber can experience a leak due to out-of-shape valves; this leakage can drop the vehicle’s compression.
  • After you adjust your engine’s valves, this will result in a better performance. You will feel that your engine becomes more responsive and smoother. This is because the engine has returned to operating at its full performance and efficiency. 

Does Each Engine Need Valve Adjustment?

Not all engines need adjustment for their valves; for example, if the motor has hydraulic compensators, it will not need any adjustment for its valves. This is because hydraulic compensators are responsible for adjusting the thermal gap automatically, and they use the help of the engine oil you supply the vehicle with. 

However, these types of engines can also face the same symptoms as normal engines when their valves are out of shape. This is because the hydraulic compensators can also tear and wear over time, and they cause the same symptoms.

When should the valves be adjusted?

You might need to look this up in your manual depending on the make, model, and engine of your car. In most cases, this treatment is only performed every 50,000 to 80,000 kilometers (31,000 to 50,000 miles). However, routine inspections are also recommended.
Especially if the vehicle has an LPG installation because LPG fuel puts more heat strain on the engine.

When the valves are adjusted, what value should the thermal gap be?

 The temperature gap is often quite narrow, measuring between 0.1 and 0.4 mm. In this situation, it is often determined using a series of feeler gauges in steps of no more than 0.05 mm. Because exhaust valves require more thermal clearance due to their larger size and increased heat output. They have different thermal clearance requirements than intake valves.


To sum up, valves are an essential part of every engine; they are responsible for the flow of the air in and out of the engine. When the valves are not adjusted properly, they can cause a drop-down in the performance and the efficiency of the vehicle’s engine.

Out-of-shape valves can also cause leakage if the fuel in the engine through the exhaust valve, which opens at the same time the intake valve is open. The fuel leak can damage the engine and cause it to fail completely. If you ever experience any of the following signs:

  • Engine Making Tapping or Clicking Noises
  • Overheating
  • Fuel Overconsumption
  • Pre-ignition Problems

Then you should consult a mechanic as soon as possible because adjusting the valves needs a qualified and experienced person as it’s not an easy task.

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