5 Symptoms of a Bad Camshaft (and Replacement Cost)
The camshaft plays a pivotal role in engine operation, controlling the timing of your engine’s valves. When it starts to fail, several noticeable symptoms can develop.
Read on to learn about how a camshaft works, common signs of a failing camshaft, and what to expect as far as repair costs go.
See Also: 5 Signs of a Bad Cam Phaser
What Is a Camshaft?
A camshaft is a vital engine component that controls the timing of your engine’s valves. This shaft is mounted within your engine’s block and is typically made of steel or cast iron.
A camshaft features a series of raised, oval-shaped parts called lobes. These lobes are responsible for controlling “valve lift” (how far a valve opens) and “valve duration” (how long a valve stays open).
The valve lift and duration mentioned above are transferred to an engine’s valve train via corresponding lifters and push rods. Individual lifters ride along each respective camshaft lobe, rising and falling with the rotation of this lobe.
The upward force is placed upon a pushrod that rests atop each lifter. This force is then distributed to rocker arms that are positioned above each pushrod. These rocker arms then move to open and close each of your engine’s intake/exhaust valves.
The camshaft’s rotation comes courtesy of an engine’s crankshaft, via a timing chain or timing belt. This chain or belt is affixed to the drive end of both the camshaft and crankshaft, transferring rotational energy between the two. Proper timing between the crankshaft and camshaft is critical for your engine to run correctly.
Signs of a Worn or Failing Camshaft
Several common symptoms tend to accompany the failure or impending failure of an engine’s camshaft. Recognizing these symptoms is extremely valuable when diagnosing problems with your vehicle and diagnosing camshaft-related issues.
#1 – Illuminated Check Engine Light
One potential symptom associated with a faulty or failing camshaft is an illuminated check engine light. This occurs when your car’s computer detects a misfire or problems with combustion efficiency.
When your camshaft isn’t working properly, it disrupts valve timing, which the engine control module can detect. If you use an OBD2 scan tool, you might see specific codes related to camshaft position or cylinder misfires. Don’t ignore this warning, as continuing to drive with these issues can lead to more serious engine damage.
#2 – Regular Misfires
Another common sign of camshaft-related issues is a continuous or regular misfire that typically gets worse as engine speed increases. This symptom stems from problems in how your valves are opening and closing.
When the camshaft is worn or damaged, it can’t properly control valve timing, which disrupts the precise mixture of fuel and air needed for combustion. You’ll likely notice your engine running roughly, especially during acceleration, or a hesitation when pressing the gas pedal.
#3 – Abnormal Top-End Noise
You might also notice unusual noises coming from the top section of your vehicle’s engine when the camshaft is damaged. This can sound like clicking, tapping, or rattling and is often caused by problems with the valves or lifters.
As camshaft lobes wear down, they create improper clearances in the valve train, resulting in these distinctive sounds. These noises are typically most noticeable when the engine is cold and may seem to improve somewhat as the engine warms up, but they won’t disappear completely if the camshaft is truly damaged.
#4 – Stalling or Starting Issues
In severe cases, such as when a camshaft has broken, you might notice that your engine stalls or has difficulty starting. This results from the inability of an engine to breath adequately, due to a lack of rocker actuation.
When valves don’t open and close correctly, the engine struggles to maintain the combustion process needed to keep running. You might experience intermittent stalling at first, particularly at idle, which eventually progresses to more frequent stalling and difficulty starting as the camshaft problem worsens.
#5 – Reduced Fuel Economy
As a camshaft’s lobes begin to wear down, and valve lift and duration are altered, your engine’s efficiency often begins to decrease. This can result in a noticeable drop in fuel economy that gets worse over time.
Because the valves aren’t opening to the correct height or for the proper duration, your engine isn’t burning fuel as efficiently as it should. You’ll likely find yourself filling up more frequently. This decrease in fuel economy often happens gradually, so monitoring your gas mileage regularly can help catch camshaft problems before they lead to complete failure.
Camshaft Replacement Cost
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Camshaft replacement tends to be a rather costly repair. However, the exact cost can vary due to a number of factors, and is highly dependent upon the make and model of your vehicle. Generally, you can expect to pay between $1,500-$2,500 to have your vehicle’s camshaft replaced.
The cost associated with camshaft replacement is split fairly evenly between the price of a replacement camshaft plus all related components, and the labor expense for performing the work. It’s also important to understand that camshaft replacement costs can tally much higher when attempting to repair luxury or high-performance vehicles.
Related: Camshaft Position Sensor Replacement Cost
Is Repair an Option?
In certain cases, camshaft repair might be a viable method for getting your engine back in working order. When a camshaft has become lightly scuffed/scratched, showing minor to moderate wear, re-machining or reconditioning of the camshaft is possible. This machine work typically costs between $250-$500, not including labor for removal or installation.
On the other hand, camshafts that are broken, deeply pitted, or excessively worn are seldom good candidates for reconditioning. In these circumstances, complete replacement is advised. In such cases, your old camshaft can typically be used as a core exchange at the time of purchase, potentially reducing the cost slightly.
Common Causes of Camshaft Failure
One of the most common causes of camshaft failure is a lack of sufficient lubrication. Your engine’s camshaft can be damaged significantly if it doesn’t get enough oil, even for a brief period of time. This lack of lubrication typically leads to scarring and premature wear of the camshaft’s individual lobes.
Another common cause of camshaft damage is lifter-related failure. When roller lifters seize or hydraulic lifters collapse, they can put too much stress on the camshaft. Additionally, broken or damaged lifter guides can allow roller lifters to become misaligned with the camshaft, causing similar damage.
What Happens If a Camshaft Breaks?
If your engine’s camshaft breaks, you’re likely to notice quickly that something is seriously wrong. A broken camshaft typically results in significant and continuous misfires, as well as a noticeable reduction in engine performance. In some cases, your vehicle’s engine might even stall completely and fail to restart.
When a camshaft breaks, there’s also a significant risk of further engine damage occurring. Your engine’s block and/or cylinder head(s) can also be damaged during such failure. If your engine is an “interference” design, improper valve timing can result in piston-to-valve contact, which can cause catastrophic internal engine damage.
Maintenance and Prevention Tips
Following these key maintenance practices can help extend the life of your camshaft and prevent costly failures:
- Follow Regular Oil Change Intervals – Change your engine oil at the manufacturer’s recommended service intervals. Fresh oil provides proper lubrication to your camshaft and prevents premature wear of the lobes.
- Use the Correct Oil – Make sure that only use oil of the proper viscosity and quality rating when servicing your vehicle. Using the wrong type of oil can accelerate camshaft wear.
- Service Timing Components – Have your timing belt or chain serviced at the intervals specified in your owner’s manual. A worn timing belt or loose chain can affect camshaft operation and potentially cause damage.
- Warm Up Your Engine – Allow your engine to warm up properly before driving aggressively, especially in cold weather. This gives the oil time to circulate and properly lubricate the camshaft.
- Avoid Over-revving – Try not to push your engine to excessively high RPMs, especially when the engine is cold. This puts additional stress on the camshaft and valve train components.
- Address Check Engine Lights – If your check engine light comes on, have it diagnosed right away. Early detection of camshaft-related problems can prevent more serious damage.
- Listen for Unusual Noises – Pay attention to any new or unusual engine noises, particularly tapping or ticking sounds from the top of the engine, and have them investigated by a qualified mechanic.
- Consider Oil Additives – For high-mileage engines, consider using oil additives designed to improve lubrication and reduce friction, which can help protect aging camshafts.
Types of Camshafts
If it gets to the point of needing to replace or repair your camshaft, knowing the different types can help you make the best choice going forward. Here are the most common camshaft types you’ll encounter, especially in modern cars.
1 – Stock Camshafts
These are the camshafts installed by the manufacturer in your vehicle. Stock camshafts are designed for everyday driving, emphasizing reliability, smooth operation, fuel efficiency, and a balanced level of performance. For most car owners, sticking with a stock camshaft is the best choice when it comes to replacements.
2 – Variable Valve Timing (VVT) Camshafts
Many modern engines use variable valve timing technology, allowing the camshaft’s operation to adjust automatically based on driving conditions. This helps optimize fuel efficiency, reduce emissions, and improve power across a wide range of engine speeds.
3 – Hydraulic Camshafts
Hydraulic camshafts work with hydraulic lifters, which use oil pressure to automatically maintain proper valve clearance. This results in quieter operation and less maintenance compared to older solid lifter designs. Most modern vehicles use hydraulic camshafts for everyday convenience and reliability.
4 – Roller Camshafts
Roller camshafts use lifters with small rollers that ride on the camshaft lobes, reducing friction and wear. This design is common in many newer engines and can help extend camshaft life while supporting better performance and fuel economy.
5 – Performance Camshafts
For drivers seeking more power, performance camshafts feature more aggressive lobe profiles to increase horsepower and torque, usually at higher RPMs. While they can boost performance, they may also result in rougher idling and reduced fuel efficiency. This makes them best suited for enthusiasts or those who use their vehicles for racing or spirited driving.
6 – Solid (Mechanical) Camshafts
Solid camshafts are typically found in older or high-performance engines. They require solid lifters and periodic manual adjustment to maintain proper valve clearance. While they offer precise valve control at high RPMs, they’re less common in everyday vehicles due to the extra maintenance required.
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