Rocker arms, just like other engine parts, contribute to the overall functionality of the engine. If anything goes wrong with even one rocker arm, your car won’t run well.
In some cases, it won’t run at all. You probably might not know something is wrong with them until you start hearing unusual noises.
So, if you start hearing weird noises from your valvetrain or engine, check it out. They are likely to be the symptoms of a bad rocker arm. Rocker arms can last for a very long time. But if not cared for, they wear off and affect the engine.
So, knowing when they are bad and getting them fixed is crucial. In this article, I will walk you through what rocker arms are, what they do and how to know they are faulty. After which you will learn their repair and replacement cost. But first, what is a rocker arm?
What Is Rocker Arm?
Now before we dive into more complex topics, let’s cover some of the basics and learn what the rockers are in general.
Knowing this stuff will help you out understand how you can tackle this issue on your car more easily. If you are already familiar with these components you can jump to one of the following chapters, if not, keep up with us for a bit.
Are these rocker arms like to rock? Well, close enough. These are components that serve a good purpose on your engine.
The rockers are mounted basically on each pushrod engine. A pushrod engine is an engine design that implements pushrods to open and close the valves.
The rockers are there to serve as a bridge between the pushrod and the valve. They transfer the energy and help open and close the valves.
When the rod is pushing, the valve opens up. Once the valve is open then the camshaft spins and releases the pressure on the lifters and the rod retracts with the help of the spring that is on the valve.
Overall, these components have a really simple task and that is to transfer the force from the rods to the valves and do this precisely every time in order for the proper combustion to be achieved.
Types of Rocker Arms
There are three types of rocker arms based on how they were manufactured: forged, cast, and stamped steel.
#1. Forged.
Forged rocker arms are the strongest among the three because they require expensive manufacturing operations. They usually have bushings and bearings that help reduce friction and increase durability.
#2. Cast.
Cast rocker arms are not as strong as forged rocker arms, but they’re satisfactory for passenger-vehicle service. They also cost less than forged rocker arms.
#3. Stamped Steel.
Among the three types, stamped steel rocker arms are considered the most cost-effective and lightweight type.
What Does Rocker Arm Do?
The purpose of a rocker arm is to move the intake and exhaust valves when the camshafts are not mounted directly above them.
They are most commonly used on engines without overhead camshafts, where push-rods are located between the camshaft and rocker arms.
The rocker arm is designed to reduce the cam follower and push rod’s movement while maintaining the required valve lift. To do this, the most rocker arms have a motion ratio of around 1.5:1.
Symptoms Of Bad Rocker Arm
The most common symptom of a bad rocker arm is clicking or ticking noises coming from the cylinder head of the engine. It can also cause misfires or a stalling engine together with a check engine light on your dashboard.
If you suspect that your car has a damaged rocker arm, the chances are that your vehicle is showing some of these signs. Here is a more detailed list of the signs of a bad or failing rocker arm to look for:
#1. Clicking or Ticking Noises.
If you hear a clicking or ticking noise when you start your engine, a worn rocker arm might be the problem.
There are also various other reasons that a clicking or ticking noise might be occurring. Once you’ve ruled out any external causes, you can start worrying about internal issues like a broken rocker arm.
If you hear a clicking or ticking noise and suspect a broken rocker arm, listen to see if the noise is coming from the top of the engine. If it’s a V-shaped engine, the noise will only be coming from one side.
Once you’ve identified the location of the ticking or clicking noise, the only way to verify that it’s a broken rocker arm is to tear apart the top end of the engine and look at what’s going on.
#2. Misfires or Stalling.
The rocker arm controls the amount of time each intake and exhaust valve is open, so it makes sense that if one of them isn’t functioning correctly, you’ll notice some performance issues. While weaker than normal engine performance is typical, a stalling engine is not.
While it’s certainly possible, most engines can run if one cylinder is misfiring or not functioning correctly.
You’ll notice the drop in performance, but if an engine is stalling because of a single worn or broken rocker arm, chances are there’s another problem you’ll need to address too.
#3. Check Engine Light.
There are tons of sensors monitoring your engine’s performance. Everything gets checked and verified for proper function. So, while there’s no sensor for each rocker arm, the decreased engine performance can easily lead to a check engine light.
The exact code on that light will vary because the broken or worn rocker arm’s side effect tripped it, not the rocker arm itself.
That’s not to say that the code won’t mention a rocker arm – it definitely can – but it might point you towards an actuator or a switch when that’s not necessarily the problem – but it could be!
#4. Physical Deterioration.
Once you suspect a broken or worn rocker arm, the only way to 100 percent verify that the rocker arm is the issue is to remove the valve covers and see what’s going on underneath.
If your vehicle has worn rocker arms, you’ll notice excessive play or metal underneath the rocker arm. If the rocker arm is extremely damaged, you might even find a cracked rocker arm.
If you’re not sure, compare the rocker arms against each other – they should all look the same. If any rocker arm shows signs of wear or damage, you should replace them all.
Causes of a bad Rocker Arm
- Bad Fuel Injectors: Defective injectors incompatible with the vehicle are the most common causes of bad rocker arms.
- Contaminated Fuel: Old or contaminated fuel is one of the most common causes of a bad rocker arm. A contaminated or insufficient fuel supply may stop the engine from working.
- Bad Manufacturing: The bad manufacturing of rocker arms is one the most common factors of their failure. This comprises any effects that cause cracks and increased stresses in the assembly. In the literature, improper heat treatment is believed to be the primary cause of maximum failures.
- Damaged Valves: If the engine valve is damaged, it will remain open. Most commonly, poor engine timing damages the valves.
- Contaminated Oil: Old or contaminated oil may also cause bad rocker arms. Your vehicle must have sufficient and clean engine oil to work the rocker arms efficiently.
- Engine Overheating: Engine overheating is one of the most dangerous things that you must avoid. It may damage different parts of the vehicle or cause complete engine failure. Different factors lead to engine overheating, including a bad radiator or insufficient coolant.
- Damaged Timing Chain or Belt: A bad timing belt can prevent the engine from starting or turning. This can damage rocker arms, push rods, and valves.
How to Diagnose a Bad Rocker Arm at Home?
#1. Listening Test.
You can check for a bad rocker arm by listening to your engine. Start your car and open the hood. Listen for a ticking sound from the top of the engine.
I use a special tool to hear engine noises better. It’s called a mechanic’s stethoscope. But you can use a long screwdriver too. Just be careful not to touch moving parts.
A bad rocker arm makes a sharp, metallic sound. It gets faster when you press the gas. It’s different from other engine noises. Once you hear it, you’ll know what I mean.
I taught my son how to do this test. He can now spot rocker arm problems just by listening. It’s a skill that comes with practice.
#2. Using Engine Diagnostic Tools.
An OBD-II scanner can help find rocker arm problems. This tool reads codes from your car’s computer. You plug it into a port under your dashboard.
Look for codes like P2646, P2647, or P2662. These codes point to valve train problems. They don’t prove you have a bad rocker arm. But they give you a good clue.
Some scanners show live data. They can tell you which cylinder is misfiring. If one cylinder keeps misfiring, its rocker arm might be bad.
I use these tools every day in my shop. They save me a lot of time guessing what’s wrong. They help me find problems faster.
#3. Visual Inspection Steps.
To see if a rocker arm is bad, you need to look at it. This means taking off the valve cover. Here’s how I do it:
- Make sure the engine is cool
- Disconnect the car battery
- Take off parts blocking the valve cover
- Remove the valve cover
- Look at each rocker arm with a bright light
- Check for cracks, wear, or loose parts
- Look for metal bits in the oil
Be careful if you try this at home. Engines have many small parts. It’s easy to lose something or put something back wrong.
I’ve been doing this for 20 years, and I still take my time. It’s better to be slow and careful than fast and make a mistake.
When to Get Professional Help
Sometimes you need a mechanic to help you. Here’s when I’d say it’s time to call a pro:
- If you’re not sure what’s wrong
- If your car runs very rough
- If the check engine light is flashing
- If your car won’t start
- If you’re not comfortable taking things apart
I’ve seen many customers try to fix things themselves. Some do great. Others make the problem worse. It’s okay to admit when you need help.
A good mechanic can find the problem fast. They have the right tools and experience. They can also spot other issues you might miss.
Remember, it’s better to pay a little now than a lot later. A small problem can become a big one if you wait too long.
How to Fix A Rocker Arm?
You can fix a rocker arm yourself or have a professional do it. To do this, first, remove the faulty rocker arm. Then, replace it with a new one. But before you start, ensure that your tools box and work light are close by.
To Remove
- Open your car’s engine cavity; locate the negative battery cord and disconnect it.
- Remove the cover from the assembly of the air cleaner and pop out the air
- Get a socket and ratchet; use it to remove the nuts. Then raise the assembly from the engine
- Tag each spark plug cable with a marker and masking tape. Please take note of each plug’s location.
- Hold the spark plug cable at the end and remove each cable from the spark plug
- Clear all wires from your workspace and path
- Separate the throttle cords from the throttle body
- Remove the wire stand from the input plenum and set it aside
- Take out the bolts from the valve’s cap
- Take out the valve’s cap from the head of the cylinder
- Remove nuts from the damaged rocker arms.
- Loosen the camshaft
- Take off the rocker’s arms
To Replace
- Place the new rocker arms and torque the nuts
- Torque the camshaft
- Place the valve’s cap over the new gasket
- Install and tighten the bolts
- Install the throttle cord stand to input space and tighten it
- Attach the throttle wires to the body of the throttle.
- Plug the spark cables to the right spark according to the tag you placed when taking them off.
- Push each cable until they fall into the position
- Attach the spark plug cables to the clips.
- Put the air cleaner on the engine and tighten the nuts with a wrench. Attach the negative battery wires. Then, use a wrench to fix the nut.
Prevention and Maintenance
While rocker arm failure can occur, taking preventative measures can help extend their lifespan and prevent premature wear.
- Regular Oil Changes: Maintaining a regular oil change schedule is crucial for lubricating all engine components, including the rocker arms. Using the correct type and viscosity of oil, as recommended by the vehicle manufacturer, is also important. Clean oil helps reduce friction and wear, extending the life of the rocker arms.
- Proper Engine Maintenance: Following the vehicle manufacturer’s recommended maintenance schedule can help identify and address potential problems before they lead to rocker arm failure. This includes checking and adjusting valve clearances as needed.
- Avoid Aggressive Driving: Aggressive driving habits, such as frequent hard acceleration and high-speed driving, can put excessive stress on the engine and its components, including the rocker arms. Driving more conservatively can help reduce wear and tear and extend the life of the engine.
- Listen to Your Engine: Pay attention to any unusual noises or changes in engine performance. Early detection of problems can prevent further damage and potentially save on costly repairs.
How Much Does A Rocker Arm Repair Cost?
Rocker arms repair costs between $500 – $1500. And almost all the money mentioned here goes into labor. Normally, the price of a rocker arm is around $5 – $20. But that’s not the only thing needed to repair it.
For example, there are some gaskets you will need to remove in other to access the faulty rocker arm. So you will end up replacing all the gaskets connected to it. In other cases, you may drain out oils which cause money to replace.
Rocker arms get worn out almost the same time. So to save labor cost, ensure the expert checks all. Because the labor cost to change one is the labor cost to change all. So you might only need to spend extra money on buying an extra rocker arm.
However, do not try doing it yourself because of the expensive labor cost. This process requires technical know-how. So give it to an expert to do.
FAQs.
Q: What Does A Loose Rocker Arm mean?
Not only a bad rocker arm can limit an engine’s performance. A loosed rocker arm can do the same. When a rocker arm is loose, it means that the rocker arm bolts in your engine are not tightened well. But what causes a rocker arm to come off?
This could be from the manufacturer’s end or you trying to adjust rocker arms at certain times. Other causes could be a bad valve seat or faulty valve springs.
A loose rocker arm noise is also like a sewing machine ticking and clicking rapidly. So whenever you hear that sound, it may be that you have a loose or a bad rocker arm.
Q: How Do You Tighten Rocker Arms?
To tighten your loosed rocker arms, simply do the following?
- Start the engine
- Remove nuts until your engine starts clicking
- Slowly tighten the nuts until the clicking stops
- Tighten again, but this time in a quarter(¼) turns
- Do them one after the other until you tighten all the loosed rocker arms.
You may need to get new nuts because nuts tightened and loosened over and over would not be able to hold properly.
Q: What Are The Various Designs Of A Rocker Arm?
There are different types of rocker’s arms specially designed for specific vehicles. Their durability and friction levels make them different from each other.
But what makes each special is the way they move a car’s camshaft. Please note that not all rocker arm fits all engines. So ensure you use the one recommended for your engine.
- Roller-tipped rocker arms: Made with aluminum, these types of rocker arms have rollers on their tip. Thus, help to reduce friction and prevent valves from wearing out. This rocker arm also helps to increase horsepower.
- Shaft rocker arms: This one has a shaft that passes through the rocker arm’s head that helps to generate rigidity. With rigidity in the valve train, you have more control over the car’s engine.
- Stampede steel rocker arms: Fast and easy to produce, they are the most used rocker arms.
- Center pivot rocker arms: This type does not use pushrods. Instead, they use a camshaft to push the rocker arms.
- End Pivot Rocker arms: This rocker arm has a pivot point at its end. With the camshaft in the middle to push down on the end pivot region.
Q: How Long Can You Drive With A Bad Rocker Arm?
I have seen people drive with a bad rocker arm. But how long can you drive with a bad rocker arm? I won’t advise you to drive with a bad rocker arm.
Not only will it limit your engine’s performance. It will cause the valves to malfunction and damage the cylinder connected to the bad rocker arm.
Last words
The most common symptom of a bad rocker arm is the tapping sounds coming from the engine. However, try to take note of other symptoms like the engine check light. And ensure you replace the bad rocker arm immediately.
A bad rocker arm would not just obstruct the functionality of the valves and lower the engine’s performance. But you may also experience engine starting problems.
The process of replacing a faulty rocker arm is technical. So using an expert to do it might be a wise thing to do. Making mistakes while fixing them yourself may rise to worse problems.