What is an Oil Control Valve (VVT Solenoid)? | Symptoms of a bad VVT Solenoid

One of the most significant innovations in the automotive industry is the variable valve timing (VVT) solenoid. It is also known as the oil control valve (OCV). The oil control valve (OCV) increases the efficiency and performance of internal combustion engines. However, the efficient working of the VVT solenoid is very important for the efficient working of the engine. This article mainly explains the symptoms, location, and causes of a bad oil control valve.

What is an Oil Control Valve?

Variable valve timing (VVT) solenoid or oil control valve controls the oil flow according to the engine speed and load. VVT solenoid is a vital part of the variable valve timing system.

Oil Control Valve

A healthy oil control valve helps to improve fuel efficiency and engine performance. VVT solenoids or oil control valves control how much oil is sent to the camshaft when the engine is idling.

Keeping the oil flow low at idle will reduce car oil pressure and allow the car to run more smoothly at idle. The continuous use of this solenoid can clog the screen and disconnect the solenoid from the actual VVT pressure switch. As it won’t be inspected during routine maintenance, you will only interact with it when it breaks.

VVT solenoid and switch failures are most commonly caused by poor maintenance. Having dirty oil can cause sludge to clog the screen of the solenoid, resulting in failure. The proper supply of engine oil is very important for the efficient working of the VVT. The VVT will not work efficiently if your vehicle doesn’t have sufficient oil.

The common symptoms of a faulty oil control valve or VVT solenoid are the check engine light illumination, poor fuel economy, a reduction in engine performance, rough idling, or reduced vehicle speed.

Function of VVT Solenoid

VVT technology is found in almost all modern cars to improve fuel economy and performance. Through electronic principles of electromagnetism, the solenoid valve controls oil flow to the camshafts to ensure the engine performs at its best while maintaining driveability at lower RPMs. VVT solenoid opening and camshaft timing is adjusted when power and signal are sent to the solenoid from the ECU.

Working of Oil Control Valve

Working of oil control valve

  • The oil control valve or variable valve timing solenoid works according to the oil pressure. It gets direction from the engine control unit (ECU) to change the camshaft rotation.
  • This valve changes the flow of oil in the channel to the camshaft phasers.
  • Depending on which conduit the solenoid will use, conduits can be instructed to speed or delay intake valve opening.
  • In order to optimize fuel delivery to the combustion chambers, the PCM will adjust the intake pressure.

Bad Oil Control Valve Symptoms

As the oil control valve goes bad, it gives one of the below-given symptoms:

 1) Rough Idling

The oil control valve alters the camshaft timing when your car is in idling condition. To achieve smooth idling, the VVT solenoid helps to make it as smooth as possible. If the camshaft timing is too slow, the engine will have a hard time revving too low and stalling.

rough idling due to a faulty VVT solenoid

If you notice strange idling problems in your car, it may be caused by a faulty oil control valve (or VVT solenoid).

 2) Poor Fuel Economy

A reduction in fuel economy or poor fuel economy is one of the most common symptoms of a bad VVT solenoid or oil control valve.

Poor fuel economy due to faulty oil control valve

The main function of the variable valve timing is to maximize engine performance and reduce fuel consumption by opening and closing valves at the right time.

A bad VVT solenoid can compromise the whole system, resulting in incorrect intake and exhaust valve operation. Normally, this results in an extreme reduction in fuel economy.

3) Low Engine Performance

A reduction in engine performance is a clear symptom of a bad or faulty oil control valve. By using the oil control valve, the engine power is increased at a higher speed while engine performance is maintained at a lower speed. A faulty valve will not alter the camshaft timing during acceleration, resulting in a significant drop in engine performance.

poor engine performance

4) Check Engine Light Indication

Modern cars contain a check engine light located on the dashboard. All car parts are monitored and controlled by the engine control unit (ECU). As the VVT solenoid goes bad, the ECU sends a code to the check engine light, and it starts illuminating.

check engine light

5) Rough Acceleration

In order to ensure smooth and effective engine operation at all RPMs, the variable valve timing solenoid adjusts the camshaft timing. Having a faulty VVT may cause your acceleration to be rough, and it may even cause misfires when accelerating.

Rough Acceleration due to faulty oil control valve

If you experience rough acceleration along with a check engine light on your dashboard, it is definitely a VVT solenoid or oil control valve issue.

6) Rattling Noise from the Engine

A faulty oil control valve may sometimes stop the VVT actuator from receiving sufficient oil pressure. This can result in the engine making rattling noises. Some manufacturers provide technical service bulletins (TSBs) to address this issue.

Rattling Noise from the Engine

Read More: Symptoms of a bad Knock Sensor

Causes of a bad Oil Control Valve

Following are the common causes of a bad oil control valve:

  • Low engine oil
  • Dirty engine oil
  • Engine overheating 
  • Old engine oil

1) Low level of Engine Oil

Insufficient engine oil is one of the common causes of a bad oil control valve or VVT solenoid. Therefore, it is important that you change your engine oil as recommended by the manufacturer in order to avoid this situation. Other engine parts and sensors like MAP sensor, O2 sensor, and MAF sensor may also affect due to insufficient engine oil.

Read More: How to Change Engine Oil?

2) Dirty Engine Oil

For the efficient working of the oil control valve or VVT solenoid, your engine oil must be clean, free of debris, or have lost some of its viscosity or lubricity.

The passages from the solenoid to the VVT chain and gear tend to clog up when engine oil becomes contaminated with debris, dirt, or other solid contaminations. Gear drive, VVT chain, and VVT solenoid damage could occur if you don’t change your engine oil according to the recommended schedule.

3) Engine Overheating

When the engine overheats, it may also damage the VVT solenoid. The engine may overheat due to multiple reasons, including insufficient coolant, a bad radiator, or a blown head gasket.

Read More: Causes of Engine Overheating

Oil Control Valve replacement cost

The oil control valve replacement cost varies according to the car model, the nature of the repair, labor costs, and your living area. The average replacement cost of the oil control valve is from $80 to $520. In this cost, the costs of the part are from $50 to $210, while the labor cost is from $310.  

How to Clean Oil Control Valve (VVT Solenoid)

The proper cleaning and maintenance of the VVT solenoid are very important for the efficient working of the vehicle. Follow the below-given steps to clean your oil control valve or VVT solenoid properly:

1) Find the VVT Solenoid

The oil valve or VVT solenoid is usually installed around the valve cover. Depending on the vehicle model, it could be in front, behind, or on top of the valve. Alternatively, you can look at the manufacturer manual to see where the VVT solenoid is located. Keep your hands away from the engine while it’s hot to avoid burning them.

2) Remove the VVT solenoid

Detach the electrical harness connection from the solenoid by simply pulling it apart.

3) Spray the Solenoid with mass airflow sensor cleaner

Wipe a clean towel over the variable valve timing solenoid while wearing safety goggles and gloves. Now, spray the solenoid down with the mass airflow sensor cleaner.

Make sure that the cleaner gets into all holes of the solenoid. Once the dirt has been removed, again spray the solenoid. A battery will be needed to properly clean the solenoid. The battery will help to close and open the solenoid.

4) Dry the VVT Solenoid

Before installing the variable valve timing solenoid, let it dry once it has been properly cleaned. It is pretty easy to clean out the mass airflow sensor cleaner. It might take a little longer if you utilized a valve cleaner or WD40.

5) Test the solenoid

After cleaning and drying, it is recommended to perform a test on the VVT solenoid. You may also move it manually to confirm that it is moving freely. A battery and two alligator clips can also be used to test it.

6) Reinstall the VVT Solenoid

After confirming that the variable valve timing solenoid is operating efficiently, it needs to be reinstalled. Put all the bolts back in their original place and install the solenoid. Once the electrical harness has been reattached, you can proceed to the next step.

7) Delete any error codes

Check engine light or error codes may cause due to a bad variable oil control valve. After you have completed the cleaning and checked that the VVT solenoid is working, you should use a diagnostic tool to remove the error codes from your vehicle. 

FAQ Section

How do I locate a Variable Valve Timing Solenoid?

Near the front of the valve cover, the VVT solenoid is installed at the engine front.

What is the lifespan of VVT solenoids?

The oil control valve or VVT solenoid service life varies according to the quality of the valve manufacturing and maintenance. The normal lifespan of the oil control valve is in between 1 to 3 years.

Is it possible to drive with a bad VVT solenoid?

Although a bad VVT solenoid can technically keep you driving, but it may also cause long-term damage to other components. Therefore, you must fix the issue quickly to prevent yourself from an expansive repair.

Does VVT solenoid cause low oil pressure?

The latest VVT system uses engine oil pressure (hydraulic pressure) and an electronic solenoid to adjust the duration, lift, and timing of the valve. Low oil pressure is also a symptom of a bad VVT system.

What are the causes of a bad VVT Solenoid?

A VVT solenoid may go bad due to multiple reasons. However, old oil, dirty oil, and low level of oil are the major causes of a bad or faulty VVT solenoid.

How do I know if my VVT solenoid is bad?

As the VVT solenoid is bad, it gives one of the below-given symptoms:

  1. Engine misfires at idling
  2. Poor Fuel Economy
  3. Rattling Noise from the Engine
  4. A reduction in engine performance
  5. Illumination of the check engine light  
  6. Rough Acceleration
Read More
  1. Symptoms and causes of a bad Cooling System
  2. Different types of Engines
  3. Working of Oil Cooled Engine
  4. How to clean Oxidized Aluminum Engine Parts

Leave a Comment