cam phaser

Understanding Cam Phaser

The cam phaser is a mechanical part that enables the camshaft to modify the timing of the valves in response to changing vehicle RPM in order to improve engine efficiency. When a cam phaser malfunctions, it can harm your engine’s VCT solenoid, which regulates the timing of the engine valves by allowing oil to flow through it at a specific pressure. The check engine light will also come on due to the ECU unit. Numerous issues, such as knocking and difficult idling, might affect the engine.

cam phaser

Vehicles’ cam phaser problems can also result in broken or bent camshafts, fractured heads, damaged valve lifters, damaged rocker arms, etc. As a result, your engine won’t rev up to its maximum capacity. You’ll hear that your engine doesn’t seem to be revving up. Additionally, the engine will seem slow and have poor acceleration.

In this article, we’ll delve deep into the cam phaser. Nevertheless, the answers to the following questions will be discussed:

  • What is a cam phaser?
  • How does it work?
  • What causes a cam phaser failure?
  • Can You drive with a bad cam phaser?
  • What Are the Signs That My Cam Phaser Is Bad?
  • Does It Make Sense to Replace Cam Phasers?
  • How much does a cam phaser replacement cost?

So, let’s get started!


What is a cam phaser?

A cam phaser is a device that modifies the engine’s valve timing so that it runs more smoothly and efficiently. The intake and exhaust valves in the cylinder are opened and closed by the camshaft, which is adjusted by the cam phaser. The camshaft is linked to the cam phaser. Typically, it is a hydraulic type that modifies the engine’s valve timing using oil. In this way, a cam phaser controls emissions, horsepower, and engine efficiency.

How does it work?

A cam phaser’s primary function is to modify the engine’s camshaft’s position. It is a component of the VVT system that aids in adjusting the camshaft position to get the ideal valve timing for the motor’s best performance. The phasers are computer- and hydraulically-controlled. One is located at the end of each engine camshaft.

The VVT solenoid, also referred to as the oil control solenoid turns each one on. The oil pressure that is applied to the cam phaser is controlled by this solenoid. Each will have its own solenoid in it. Some automobiles come equipped with phasers for the intake and exhaust camshafts.

There are other variants, though, that have just one phaser. This one phaser may be located on the intake or exhaust camshaft depending on the vehicle model you drive. The rotation of the camshaft is carried out by cam phasers. When necessary, this action aids in closing and opening the valves.

The phasers open the valves at precise moments while the engine is running at lower RPMs to boost performance and increase throttle responsiveness. The valves are timed differently at higher RPMs to increase fuel efficiency and decrease hazardous emissions.

What causes a cam phaser failure?

The following are the main causes of a cam phaser failure:

  • Low Oil Pressure and Engine Wear
  • Internal Cam Phaser Wear
  • Problems With the Engine’s Electrical Control Unit
  • Sludge And Debris
  • Flawed ECU
  • No Oil Changes Are Made
  • Gear/Sprocket damage

Low Oil Pressure and Engine Wear

Wear in the engine is a sign that the phaser isn’t receiving enough oil flow. More oil is lost through the crank, engine rod, and cam bearings as the engine ages. The cam phasers receive insufficient oil delivery because they are the final component to receive oil. Consequently, the cam phaser shakes back and forth.

The 5.4L V8 engine experiences the most cam phaser problems as a result of low oil pressure. Due to phaser wear or a lack of oil pressure, the variable cam timing phasers in the Ford 5.4L engine could no longer be controlled by the ECU, which caused problems. Ford switched to the 411-horsepower 6.2-liter V-8 in 2010 to replace the 5.4 V-8 for this reason.

Internal Cam Phaser Wear

Typically, the excessive cam phaser noise and cam phaser failure are the results of a mixture of both forms of wear. The variable cam timing cannot be controlled by the ECU and the oil flow cannot be adequately monitored if the cam phaser is worn out.

Problems with the Engine’s Electrical Control Unit

The engine’s actuators are managed by the engine control module. Your cam phaser could stop working if the computer loses control of it.

Sludge And Debris

To ensure that the oil lubricates the camshaft correctly, it must pass through each component. The oil flow will be hampered if there is debris in the oil, which will prevent the oil from adequately lubricating the engine’s parts. As a result, the cam phaser will experience higher engine wear.

Flawed ECU

The ECU is in charge of regulating the cam phasers. The phaser could malfunction if a bug prevents the computer from doing its function. These ECU issues can be promptly identified with the best code scanner. You may make sure the phasers continue to operate as intended by fixing them.

No Oil Changes Are Made

Oil changes are required after a particular number of miles have been logged on the car. Oil pressure drops as a result of the oil being drier over time from the heat of the engine. Additionally, the oil gets contaminated, which has an impact on how well the engine’s components perform.

I also want to emphasize the fact that cam phasers are regulated by oil pressure via a solenoid. Because of the low oil pressure, if the phaser’s pins don’t lock, the timing of the valves will be thrown off, and the engine will idle and operate poorly.

The Environmental Protection Agency’s (EPA’s) fuel efficiency recommendations are followed by vehicle manufacturers in the USA, who advise using lighter oils like 5w20 rather than heavier ones like 5w30 or 5w40. To ensure that engine parts operate effectively, thinner oil needs to be changed more regularly, typically every 3 to 5 miles.

Gear/Sprocket damage

Additionally, motor oil aids in lubricating the gears and sprockets. These expensive components will prematurely break if there is too much friction, which will cause issues with the cam phaser. You can always add friction modifiers for less wear if you are concerned about proper lubrication. The best oil producers of today, however, offer everything required to maintain the engine operating smoothly.

Can You drive with a bad cam phaser?

You shouldn’t drive your car if you are aware that the cam phaser is worn out. You put the car at risk by continuing to drive even if it keeps running without too many interruptions. The exhaust or intake valves, the ECU, the motor, the solenoids, or the VCT could all sustain further damage from the defective phaser.

You could end up with a bigger charge down the road by delaying the repair. While driving, you can also unexpectedly lose power. You run the possibility of getting into an accident because of this issue, and other drivers on the road are also put in danger. When you can get the vehicle fixed, there’s no need to put other people in danger.

What Are the Signs That My Cam Phaser Is Bad?

Lower engine performance and a dashboard check engine light are the two most typical signs of a bad cam phaser. The engine may also sound noisier than usual, which is a sign that you need to inspect and fix it right away. Here is a more detailed explanation of warning signals to look out for with a cam phaser:

  • Noises of Rattling
  • Engine Performance Drops
  • The Check Engine Light

Noises of Rattling

When the engine is running at its base idle, the cam phaser should lock into place. However, it might not be able to lock in place if the phaser has failed. A knocking or rattling sound is the end outcome. It should be audible coming from the motor’s top. When the engine is idling or after it has warmed up, it is simpler to hear.

Engine Performance Drops

To make sure the engine performs as planned, the valve timing needs to be optimized. Timing will be advanced or delayed if the cam phaser isn’t working properly. The engine’s performance will suffer as a result of either of these difficulties. You might experience difficulties with acceleration, a rough idle, or obtaining all of the power it often produces.

Check Engine Light

Anytime a system malfunctions, the auto computer will alert you. The positioning of the camshaft is continuously tracked by sensors with the aid of the powertrain control module (PCM). The Check Engine Light will come on if the module receives a subpar reading from the sensors. Although there may be other causes for this placement issue, the cam phaser is frequently the culprit. You should be able to pinpoint the issue more precisely by using your expert scanner to examine the diagnostic trouble codes.

Does It Make Sense to Replace Cam Phasers?

Yes, if they are defective or damaged. If damaged cam phasers are not replaced, they can harm a VCT (Valve control timing) system, resulting in engine exhaust valve timing issues. The cam phaser’s drawback is that it has a small mechanism that can become jammed.

When a cam phaser becomes stuck, it can harm an engine’s intake and exhaust valves. As a result, both valve timing issues would result in a reduction of power. When your cam phaser illuminates the check engine light, it is time to replace it, in my opinion.

How much does a cam phaser replacement cost?

Cam phasers typically cost between $750 and $2,500 to replace. This is not an easy task, and most beginners won’t do it on their own. However, the overall cost varies depending on the kind of automobile you drive and the shop you use to fix the car.

Doing the repair yourself will save you some money. But if you don’t know what you’re doing or don’t have the necessary instruments, you might do more harm than good. Instead, leave this sophisticated repair to the experts.

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Watch the video below to learn more


What are the symptoms of bad cam phasers?

  • When the engine is heated, you hear a tapping or rattling sound at idle.
  • The engine has terrible performance.
  • The engine light turns on. A cam sensor or actuator code may be shown, alerting you that the camshaft is not in the desired position.

What does a cam phaser do?

A computer-controlled servo is used to calibrate a cam phaser, which is a sprocket that moves an engine’s camshaft in proportion to its crankshaft. Engine intake and exhaust valve timing, which is controlled by camshafts, determines how aggressively an engine performs.

How much does it cost to replace cam phasers?

Cam phaser replacement is not cheap. If you want the work done by a professional, you should be prepared to pay anything between $750 and $2500. Of course, a number of variables, like the vehicle’s year, make, and model, will affect the total cost.

What Ford engines have cam phaser issues?

The list of Ford Engines with Cam Phaser issues is provided below:

  • 2018-2020 Expedition.
  • 2018-2020 Navigator.
  • 2017-2020 F-150 Raptor/Limited Variants.
  • 2018 Ford F-150 3.5-liter EcoBoost Engines.

What causes cam phasers to fail?

The two main causes of phaser failure are engine wear and wear inside the cam phasers; often, these two factors combine to produce excessive phaser noise. The computer cannot correctly manage the variable cam timing due to phaser wear, and neither can the oil.

Will bad cam phasers throw a code?

The ECU will take every precaution to safeguard the engine in this circumstance. It will enter safe (or limp) mode, which in most situations will prevent the engine from revving higher than a particular RPM. In addition, a code will be generated, and the check engine light will turn on.

Will a bad cam phaser cause a check engine light?

The check engine light will come on when the cam phasers fully stop working because time is running out. Did you hear the cold start rattle before this? The 3.5 Ecoboost has a common issue with this, and the dealer will replace the affected parts.

Will a bad cam phaser cause a misfire?

The variable valve timing will be slightly off due to defective camshaft phasers, which is a typical issue and can lead to rough idling or misfiring.

What is the knock sound on the cam phaser?

Cam timing is advanced and retracted using cam phasers. By solenoids that control variable cam timing, the oil pressure is controlled. The solenoids control oil pressure to move the timing forward or backward when instructed. A portion that isn’t working properly may cause the pressure to drop, which will sound like knocking.


As you are already aware, the cam phaser is a mechanical component that enables the camshaft to alter the valve timing in response to shifting vehicle RPM in order to increase engine efficiency. Misaligned camshaft timing is one of the more serious problems that can result from a failed cam phaser.

Therefore, it’s crucial to address the problem as quickly as feasible. Ignoring these signs could result in significant engine damage and very pricey repairs. That is all for this article. Hope you learn a lot. If so, kindly share it with others. Thanks for reading; see you around!


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