What Happens When Cam Phasers Go Bad – It’s Bad!

A cam phaser is an adjustable camshaft sprocket, which is turned via a servo that’s controlled by a servo.

This computer either advances the cam or cams at a low rate of revolutions per minute (RPM) as a means for enhancing the car’s driveability, or it can do the opposite, for a higher rate of revolutions per minute, and therefore increased horsepower.

You don’t need to know exactly how cam phasers work, though, to understand how important it is that they remain in good working order.

What Happens When Cam Phasers Go Bad – It’s Bad!

If your cam phasers go bad, this will eventually lead to damage to the car’s engine timings, the VCT solenoids, and even the engine itself. Additionally, it can also interfere with the internal combustion engine.

The following article will break down everything you might need to know about cam phasers, and what happens when they become faulty.

We’ll also be providing answers to some of the most frequently asked questions regarding worn cam phasers.

What Is A Cam Phaser?

Cam phasers are modern devices within vehicles, whose purpose is to provide valve timing in modern internal combustion engines. There are two kinds of cam phasers in any given modern vehicle: exhaust and intake.

While upon visual inspection they might look exactly the same, they don’t work the same.

The Assembly Of Cam Phasers

When cam phasers are put together, they must be assembled to a very specific standard. If not, they’re unlikely to work properly.

This would eventually damage the car in which the cam phasers were fitted, the repairs for which can be very pricey.

The parameters for cam phasers are extremely specific, which is why their assembly must be tested thoroughly, and these tests documented.

There are several things to take into account when testing cam phasers.

The pressing distance must be correct (as well as the press force), every part needs to be attached firmly to the right phaser, there must be a debris screen, and finally, the spring tension must be completely accurate; there is no room for error when it comes to the assembly of cam phasers.

Consequences Of Worn Cam Phasers

When a vehicle’s cam phasers get worn or are faulty, there are several ways this will negatively affect the said vehicle.

The most notable consequence would be damage to the engine itself, but it’s important to be aware of each of the common problems.

Worn cam phasers can lead to damage to the Variable Cam Timing (VCT) systems, and bring said systems into warm-up mode, can lead to rattling, can lessen the fuel efficiency of the vehicle (and, similarly, increase the vehicle’s fuel emissions), lessen the engine’s performance, and, ultimately, cause extensive damage to the engine.

Let’s break down each of these issues in a little more detail, before moving on to the most common indications that your vehicle’s cam phasers are worn.

Damage To The VCT Systems

The purpose of the VCT systems is to control the vehicle’s variable valve timing (including the opening and closing events of the valve), which can only be accomplished via the camshaft-phasers.

In most vehicles, it’s hydraulic valves that direct the oil pressure within the camshaft-phasers. This can apply to either the exhaust cam phasers or the intake.

When a vehicle’s cam phasers become worn or are faulty, they are no longer capable of controlling the timing of the valve. Over time this will lead to damage to the vehicle’s VCT.

Warm-Up Mode

This would be a result of the damaged VCT systems. It’s a domino effect if your cam phasers become worn, they need to be fixed, else they will continue to negatively affect your vehicle in several different ways.

The reason the components of the vehicle would warm-up is that the timing of the valve can no longer be kept under control. This will degrade the effectiveness of the vehicle’s VCT systems even further.


Another outcome of worn cam phasers is that the Electrical Control Unit (ECU) is unable to keep the valve timing gear under control, due to there being less oil pressure within the cavity of the camshaft-phasers.

This would lead to the phasers within the cavity becoming worn, which will cause a rattling sound. If you hear a loud rattling when you start up your car and you’re not quite sure what the cause is, it may be a result of worn cam phasers.

It could also mean a lack of lubrication within the cam phasers. Either way, it’s vital to get any unexplained noises checked out immediately.

Lessened Fuel Efficiency / Increase Fuel Emissions

Worn cam phasers lead to lower oil pressure, which in turn will make the solenoids within the vehicle underperform.

The purpose of the solenoids is to transmit the signal through to the phaser cavity, but if they’re not capable of executing this function, the flow of oil within the vehicle will no longer be properly regulated.

This will lessen the fuel efficiency of the vehicle, and fuel emissions will increase.

Lessened Engine Performance

When a vehicle is functioning properly, the responsibility of the powertrain control module (PCM) is to optimize the vehicle’s intake valve opening, for it to match the engine’s exact conditions.

Usually, this would increase the vehicle’s torque power and enhance the engine’s overall performance, but when the cam phasers are worn, the powertrain control module is no longer capable of controlling intake valve timing.

Thus, the engine will no longer be performing optimally.

Extensive Damage To The Engine

Functioning cam phasers not only helps the engine to perform optimally but also lowers the risk of wear and friction to the engine.

Without this measure in place, the engine will be more susceptible to both wear and friction, which can lead to extensive damage over time.

Engine Light Flickers

When a vehicle’s cam phasers have become worn or rusty, it can cause the engine light to flicker. This would be a result of a degrading Electrical Control Unit.

Signs That Your Vehicle’s Cam Phasers Are Worn Or Faulty

Several different symptoms can indicate faulty or worn cam phasers, each of which can be cause for concern because even if they’re not being caused by the cam phasers, they could be a sign of another problem with your vehicle.

The most common symptoms of worn cam phasers can include: your car feeling like it’s running rough, or like it’s lacking power but also experiencing noticeable surges when you hit the gas at 50 to 60 miles per hour.

It may also be that your vehicle is failing to reach its maximum speed.

Another symptom is your car struggling to start, or stalling without good reason (for example it could stall despite being idle).

One of the most obvious signs that your vehicle is suffering from worn cam phasers would be a failure to start at all. Another similar sign is rough idling.

You might also notice that your car runs less efficiently during the colder months. Even if the car’s performance improves once it’s had time to warm up, there’s still a chance that something is wrong with the vehicle’s cam phasers.

If your car seems to vibrate when you’re accelerating (or when you’re accelerating to certain speeds), then this could also be an indication that the cam phasers need to be replaced.

Finally, you should always get your car checked out if it seems to be overheating. This can be an indication that the cam phasers need to be replaced, but it can also be an indication of other serious issues.

Signs That Your VVT Solenoid Is Worn Or Faulty

The indicators of a worn or faulty VVT solenoid are similar to the aforementioned indicators of a worn or faulty cam phaser.

These indicators include the following: the light comes on telling you to check your engine, the engine oil seems dirty, rough idling, and a noticeable decrease when it comes to the vehicle’s fuel economy.

What Could Cause Cam Phasers To Go Bad?

What Happens When Cam Phasers Go Bad – It’s Bad!

Several different things can cause cam phasers to go bad, and in some cases, it will be a combination of more than one of these things. Let’s look at each of the most common causes in detail.

Low Oil Viscosity

It’s vital to use the correct oil for the vehicle’s cam phasers. If you’re using the wrong oil, it will eventually lead to increased friction, which will, in turn, cause the engine to be running at unsustainably high temperatures, lowering the efficiency of the engine.

If the cam phasers are using the correct oil, the right amount of oil viscosity will be guaranteed, thus ensuring the correct amount of oil pressure.

With the wrong oil, the response time of the cam phasers will be far slower than is required, which will ultimately lead to damage.

If you’re unsure of the differences between oils, make sure that you find out before applying the wrong oil to your vehicle’s cam phasers.

Insufficient Oil Pressure

Cam phasers can also become worn due to inadequate oil pressure. When a vehicle is functioning normally, the oil pressure powers the cam phasers, but this can’t happen if the oil pressure is too low.

The cause of insufficient oil pressure will either be because you’ve used a failing oil pump, or you’ve used dirty oil.

Inadequate oil pressure can wear the metal of the cam phasers themselves, which can result in lower oil efficiency.

Sludge Or Debris

Quite a simple one. A considerable amount of any kind of dirt, debris, or sludge can negatively affect a vehicle’s oil flow. This can eventually lead to the cam phasers becoming worn.

One way to prevent this from becoming an issue is using engine oil additives.

Oil Needs Changed More Regularly

You should always be changing your vehicle’s engine oil eventually. If you don’t, this will likely lead to damage to the cam phasers.

When you’re changing the oil, make sure you’re properly cleaning the engine oil system, using an engine flush designed for that specific purpose.

Remember when you’re changing the engine oil that the oil you choose must be of the right grade for your vehicle.

Electrical Control Unit (ECU) Issues

Because the Electrical Control Unit is essential for keeping the cam phasers under control, when this dynamic fails, the cam phasers will fail.

It might be worth buying an OBD2 scanner, such as the Autophix 7810 BMW Full-Systems reader. This device can help to spot issues with the vehicle’s Electrical Control Unit before they can cause further problems.

Damage To Gear Or Sprocket

Another cause of worn cam phasers can be that either a gear or a sprocket within your vehicle is damaged. For this reason, friction modifiers can be a solid choice.

How To Get Rid Of Noise From Cam Phasers

If you’re concerned about the noise coming from your cam phasers (which tends to be a rattling sound), then you should get them checked out as soon as possible. If you require a temporary solution, though, there is quite a simple process you can try.

It’s unlikely to completely rid your car of rattling noise, but it should at the very least lessen it to the point where it’s not quite as noticeable.

To reiterate, though- this is not a permanent solution. If your cam phasers are rattling, you’re probably going to need to get them replaced.

This solution comes in the form of oil treatment, which you can quite easily do yourself if you have the right tools and equipment.

Make sure you’re wearing safety gloves, and that your vehicle’s back tires are blocked with a wood blocker. Raise your vehicle with a jack, and with a 14-millimeter ratchet wrench, take out the drain plug.

It’s best to be using an oil collection pan at this stage, else you’re risking oil leaks.

Wait for the oil flow to finish. This would usually take between five to ten minutes. Once it’s done, reattach the nut, and wipe up the dirty oil with a cloth. Attach the new filter using just a dab of oil.

Lift the hood of your vehicle to access the motor oil. Take off the jack and remove the wood blocker from your vehicle, and, using an oil funnel, apply your oil treatment.

Once you’ve applied the treatment, give it at least a couple of minutes.

After this time, you should check your vehicle’s oil level, which can be done with a dipstick. Clean the surface of the engine thoroughly before shutting the hood and the engine cap.

Start up the vehicle, and leave it idle until it’s warmed up a little. You should be able to tell fairly quickly if the rattling sound is gone, or at least if it’s lessened.

If you notice no change, it may be that the problem is worse than you’d assumed, meaning the cam phasers are worn to the point where they must be replaced as soon as possible.

There’s no harm in trying the same oil treatment once more, though, using the same process. It may be that this will lessen the rattling noise.

Regardless, you should consider getting your vehicle checked out, as the cam phasers will likely need to be replaced.

How To Replace Cam Phasers

If an oil treatment doesn’t get rid of rattling noise, then you’re probably going to need to replace the cam phasers in your vehicle. But even if the oil treatment did work, this would merely be a temporary solution, so you’d need to get them replaced anyway.

Besides, there are several different reasons you might know that your cam phasers have become worn, each of which we discussed earlier in this article.

If your cam phasers need to be replaced, you might just want a mechanic to take care of them.

But you don’t need to be a professional mechanic to successfully replace cam phasers; you might be able to do it yourself. If you’re going to give it a go, follow the steps below.

First, disconnect the battery of your vehicle before taking out its air intake tube. Locate the 10-millimeter bolts on the power steering reservoir of your vehicle (there should be three of these bolts), and loosen the bolts out.

You’ll also be loosening the 18-millimeter bolt and the two 13-millimeter bolts, each of which can also be found on the reservoir bracket.

Take out the positive crankcase ventilation (PVC) tube, which can be found in your vehicle’s valve corner.

Take out all of the different wiring plugs and other electrical components that can be found on the valve corner (the ones on the driver’s side of the vehicle).

Disconnect the control module for the powertrain, as well as the mounting bracket. If this sounds like a lot of steps, don’t worry- there’s not a whole lot left to it.

Use compressed air to rid the vehicle’s valve cover of debris or dust. Once it’s free of debris, unbolt it, also unbolting the 8-millimeter bolt within the dipstick tube. Don’t take out the tube itself, though.

Take out every ignition coil pack, as well as the camshaft timing solenoid, and at this stage, you can completely remove the vehicle’s valve cover. Put your timing chain wedge tool in between both halves of your chain.

Make note of where the cam phaser is in relation to where the timing chain and the camshaft is- you can do so using a dowel pin.

Loosen the cam phaser’s bolts, and you can finally remove the cam phaser itself. Attach your new cam phaser, aligning it so it’s right where the previous cam phaser was in relation to the dowel pin.

Tighten the cam phaser’s bolts to roughly 30 ft-lbs.

Variable Duration Vs Cam Phasers

Cam phasing is generally thought of as variable valve timing (VVT) in its most simple form. In the process known as cam phasing, the angle of the camshaft phase would be rotated backward or forwards, in correlation with the vehicle’s crankshaft.

Through this process, the valves can both open and close, either later or earlier. The duration of the camshaft cannot be altered with just the cam phasers.

Variable valve timing is when the timing of the valve lift event is altered, and its purpose is to improve the fuel efficiency and overall performance of a vehicle.

Variable valve timing can be achieved via several different means, most commonly mechanical devices. Alternatively, though, it could be achieved via electro-hydraulic systems.

Vehicle manufacturers have been forced to adapt to variable valve timing as the regulations regarding emissions become more strict around the world.

What Is A Cam Phaser Lockout?

What Is A Cam Phaser Lockout?

A cam phaser lockout is often used to address certain engine problems, which include rattling and clicking noises.

Just like applying oil treatments, they’re not a permanent solution to cam phaser problems (usually, the only permanent solution is replacing the cam phaser), but as a temporary solution, they tend to work very well.

They could be deemed somewhat controversial, though, as some argue that cam phaser lockouts increase the fuel consumption of a vehicle in high revolutions per minute.

So, while there are many advantages to installing a cam phaser lockout, there may also be a significant downside that’s worth noting as well.

Let’s look in more detail at how the cam phaser lockout works, and the benefits it provides.


The main advantage of installing a cam phaser lockout is that, unlike the oil treatment solution (which is in no way guaranteed to work, especially if your cam phasers have been rattling for a while), the lockout will get rid of the rattling or knocking noise completely.

A cam phaser lockout is best suited to vehicles whose engines have at no point been exposed to damage in the past- damage that could have impacted negatively on the cam phaser.

If your engine has suffered significant damage in the past, the vehicle may not be compatible with a cam phaser lockout.

They also tend to be very affordable, especially compared to other preventative measures for your cam phaser. It can work out as half the price of other measures.

Replacing your engine can cost thousands of dollars, so if this is a feasible alternative, then you’ll be saving a lot of money.

The miles per gallon of your vehicle will also be reduced when your revolutions per minute are low. Things are a little different when it comes to high revolutions per minute, but we’ll get to that shortly.

A cam phaser can boost engine power, but when the cam phasers fail, this engine power will be significantly reduced (and can eventually lead to the engine breaking down completely).

But if you’ve got a cam phaser lockout installed, the cam phaser is far less likely to break down, meaning your engine power will remain consistent.

Generally, the efficiency of your vehicle will also be enhanced when you’re using a cam phaser lockout.

The reason for this is that the lockout helps to reduce any potential damage to multiple essential components within your car, like the chain tensioners, the pistons, and the lash adjusters.

The cam phaser lockout will maintain all these parts within your car, but to minimize the chances of damage occurring, even more, you should be regularly monitoring the health of your car.

The final advantage of the cam phaser lockout worth mentioning is that the costs of maintenance are likely to be far lower, purely because the addition of this part will greatly reduce (if not eliminate) the chances of your vehicle’s cam phasers failing.

In the long run, this will surely save you vast amounts of money when it comes to maintenance, especially if it makes the difference between needing to get your engine replaced and not needing to get it replaced.

As we’ve established, many parts would otherwise be more susceptible to damage without the installation of a cam phaser lockout.

So for every individual component that’s protected by the lockout, money will be saved.


There’s a reason cam phaser lockouts aren’t lauded by everyone, though. While driving with low revolutions per minute leads to increased miles per gallon, the opposite is true when you’re driving with high (or even regular) revolutions per minute.

So, say for every 50 miles your vehicle was consuming one gallon of fuel, meaning the vehicle’s miles per gallon number was 50.

Once you install a cam phaser lockout, your miles per gallon would likely decrease by around one mile- at least on regular or high revolutions per minute.

It’s worth noting that this is the only notable disadvantage of using a cam phaser lockout.

If you’re using it more as a temporary solution to eventually replace your cam phasers, then the advantages would likely outweigh the disadvantages.

But if you intend to be using a cam phaser lockout on a long-term basis (and this is recommended for preventing future cam phaser problems), you’ll just need to decide whether it’s worth the increased fuel consumption at high revolutions per minute.

Best Cam Phaser Lockout Kits

If you’re considering buying a cam phaser lockout kit to prevent future cam phaser issues, you might be wondering which kit to go with.

Realistically there won’t be many differences between all of the lockout kits on the market (aside from the price), but the following are some of the most reliable cam phaser lockout kits according to customers.

Engine Timing Service Tool Kit

An all-in-one engine service kit, this product is specifically designed for Ford vehicles with 4.6L, 5.4L, 6.8L 3V engines.

Every tool you could need for engine tweaks or repair comes bundled in this kit, including a cam phaser holding tool, crank pulley bolts, the cam phaser lockout kit, and a valve spring compressor tool.

The manufacturer claims that the lockout kit is a permanent solution for troublesome engine noise, but if you’re not completely satisfied they’ll offer you a full refund within 30 days.

Cam Phaser Lock Out Kit

This kit is designed for use with Ford vehicles that have a 5.4L or 4.6L three-valve engine. The kit includes a cam phaser lockout, a camshaft mounting bolt, and a timing chain locking tool.

Each tool is made from high-quality materials that are highly resistant to rust, deformation, and impact. There are five pieces to the kit in total- all the essentials.

This kit will help to greatly simplify any engine work you might need to carry out, and you may very well need to if you hear a rattling, knocking, or clicking sound coming from your vehicle’s engine.

The purpose of the chain locking wedge tool is to provide you with a little more room to take out the cam phaser. This will make it a lot easier to carry out whichever cam changes you might need to make.

The kit is compatible with a wide range of Ford vehicles, including all of the 2005 through 2010 Mercury Mountaineer V8 models, all of the 2006 through 2008 Lincoln Mark LT vehicles, all Ford 2004-2014 Lincoln Navigator vehicles, and all Ford Mustang GT 2005 through 2009 vehicles.

Which Ford Vehicles Had Cam Phaser Problems?

Between 2002 to around 2014, a lot of Ford vehicles faced common issues with their cam phasers. It’s worth bearing in mind if you’re thinking of buying a Ford vehicle from that era.

Many models until 2014 had persistent issues with their cam phasers, including Lincoln, Mercury, and Ford.

Most of the cars and trucks that had cam phaser issues had a 5.4L engine. This led to Ford Motor Company discontinuing the 5.4L engine permanently.

To get a better understanding of the importance of cam phasers (at least in vehicles that have them), let’s take a detailed look at the Ford vehicles that were most susceptible to these problems.

The 2004 to 2014 Lincoln Navigator had a 5.4L engine, and even though the model was an updated version of the Expedition (which also had serious issues), the cam phaser problems remained.

It was in the last year of this model’s production, 2014, that Ford finally ceased production of the 5.4L engine.

The 2006 to 2010 Mercury Mountaineer didn’t use a 5.4L engine- rather, it had a 4.6L engine. Still, though, this engine suffered from regular cam phaser issues.

This was another case of Ford promoting an updated model, but the model had retained all of the same cam phaser issues.

Some of the other lines of Ford vehicles that suffered from cam phaser issues were the 2004 to 2010 Ford F-150 (which used the infamous 5.4L engine), the 2009 to 2010 Ford F-150 (which used the 4.6L engine), the 2006 to 2010 Ford Explorer (which also used the 4.6L engine), and the 2007 to 2010 Ford Explorer Sport Trac (again, 4.6L engine).

Frequently Asked Questions

Get your last-minute questions answered below!

Would A Faulty Cam Phaser Throw A Code?

You will usually receive an error code if the cam phasers of your vehicle are worn or otherwise faulty.

It can depend on the actual problem, though, and as we’ve established, worn cam phasers can be caused by several problems.

When your vehicle gives you an error code (or when you receive any kind of error code), make sure that you examine it to find out what the exact problem is, and how you might be able to fix it.

In most cases, though, you’ll need to get your cam phasers switched out with new ones.

Can You Drive Your Vehicle With Worn Cam Phasers?

If you suspect that the cam phaser in your vehicle has become worn or is otherwise faulty, you must get your vehicle seen as soon as possible.

An oil treatment may help to get rid of the rattling noise that worn cam phasers can emit, but this is in no way a permanent solution.

When your vehicle’s cam phasers are worn, over time they will degrade the VCT, which can cause several serious issues. If you don’t address the issue of worn cam phasers as soon as you can, it could lead to an accident.

Is It Expensive To Get Your Cam Phasers Replaced?

It can be fairly costly to get your vehicle’s cam phasers replaced, usually somewhere in the range of $500 to $1000.

Those are the prices you’ll likely be charged by a mechanic- if you take your vehicle to a dealership you’re probably going to be paying far more, possibly as much as $3000.

What Will Happen If My Camshaft Sensor Has Gone Bad?

Your vehicle’s camshaft sensor measures both the speed and the position of the camshaft itself.

This lets the computer of the engine know when it should be injecting fuel in the cylinder, and when to open up the valve to let air inside.

When the camshaft sensor becomes worn or has been unplugged, this is one of the things that can lead to your cam phaser not functioning how it should.

This can result in engine misfires, as well as lower mileage. A lot of the time when the lights come on informing you to check your vehicle’s engine, it is because the sensor has gone bad.

What Would Cam Phaser Problems Sound Like?

The most common sounds that will come from a worn cam phaser would be knocking or rattling, but depending on the vehicle and the extent of the wear, it can sometimes sound quite different.

Whatever the sound, though, it will certainly be noticeable.

Not all worn cam phasers make the same sound, so don’t assume just because your car isn’t rattling that you’ve nothing to be concerned about. Any new, different noise being emitted from your car is worth getting checked.

These could include the more common knocking, rattling, or clicking, but there may also be what sounds like wailing or roaring.

Some car owners report that their worn cam phasers sound like a mixture between engine sounds and the sounds of a telephone, as well as other sounds that are harder to label.


Several different symptoms could indicate a worn or faulty cam phaser in your vehicle, and the first of these that you’re likely to notice would be a rattling sound coming from the engine.

If you notice any of the symptoms listed in this article, it’s vital either to check out your vehicle yourself or to take it to a mechanic.

If you don’t get your cam phasers replaced as soon as possible when you notice that they’re worn or otherwise faulty, there will be many serious consequences.

Not only will your fuel efficiency suffer, but your engine’s performance will decline, and eventually it may stop working entirely.

Neglecting cam phaser issues could lead to a serious accident, so while oil treatments can get rid of the rattling sound temporarily, you must seek a permanent fix as soon as you can.