Last Updated on April 6, 2021
Rocker arms are a lesser-known but crucial part of some types of internal combustion engines. Their deterioration can cause weak engine performance or even failure, so it’s important to know when replacement is necessary and how much the rocker arm repair cost will set you back.
What is a Rocker Arm and How Does It Work?
Rocker arms are typically located between the pushrod and intake and exhaust valves. They are pushed and pulled by pushrods to “rock” up and down, opening and closing the exhaust valve and intake valve of the combustion chamber on engines with a camshaft below the engine.
Pushrods move up and down as the camshaft below them rotates, driven by the crankshaft. In this way, power can flow from the combustion chamber of the engine through various parts to the wheels to put the vehicle in motion.
With broken or loose rocker arms, the exhaust valves and intake valves can’t function correctly and the cylinder associated with the faulty rocker arm will be disabled. This will ultimately limit the performance of your engine and your ability to drive the car smoothly and safely.
Related: SOHC vs DOHC vs Cam-in-Block Engine
Common Symptoms of a Bad Rocker Arm
Your engine may exhibit one or more of the following symptoms if one or more rocker arms is failing. Although, there may be another defective part causing the problem.
Regardless of the cause, the problem should be resolved by yourself or a mechanic before the vehicle is driven again.
#1 – Clicking or Ticking Noises
Unusual noises involving valves often sound like a rapid clicking or ticking, similar to a sewing machine. You should inspect the rocker arms and surrounding parts while the engine is running if you hear this noise. Faulty rocker arms can get stuck or ineffectively open and close the valves.
There are many other possible causes of strange noises in the combustion chamber and surrounding parts, such as lack of lubrication between moving parts, warped valves, and worn camshaft lobes.
If the rocker arms appear to be working well on visual inspection, a bit of troubleshooting done by yourself or a mechanic is the next step to solving the problem.
#2 – Weak Engine Performance or Stalling
Careful timing is everything to a functional internal combustion engine. For maximum efficiency, valves must open and close at just the right time. If the vehicle’s faulty rocker arm is getting in the way of this process, you’ll notice decreased power and poor acceleration.
In severe cases, the engine can suffer to the point of stalling while driving. Eventually, the vehicle won’t even start until the broken component is replaced.
#3 – Check Engine Light On
The vehicle will recognize weak engine performance as well, and will warn the driver by illuminating the check engine light. This signal should never be ignored. You’ll want to use a diagnostic scanner to check for any stored codes.
Some examples of rocker arm related DTC codes include P2646 (A rocker arm actuator system performance or stuck off bank 1), P2647 (rocker arm oil pressure switch), and P2662 (B rocker arm actuator sys stuck on bank 2)
#4 – Physical Deterioration
Visual inspection of the rocker arms can also reveal any cracks or wear. After removing the valve cover, look for pieces of metal below the rocker arms, as they can grind on the pivot point and valves when they are in poor condition.
Degraded rocker arms should be replaced even if no other symptoms are present, because problems will soon follow.
Replacement and Repair Cost
A single rocker arm itself costs between $15 and $60 depending on the vehicle and whether it’s an intake or exhaust rocker arm.
Rocker arm kits, which typically cost between $100 and $500, include other necessary components like guide plates and pushrods, and may be the better way to go if you are confident that you can perform the replacement job yourself.
Often the rocker arms all fail around the same time, so replacing them all at once would be a good idea. This makes the full kits the most common purchase option.
Because rocker arm repair is tedious work, it can be time intensive so hiring an auto mechanic or dealership to do the job is not cheap. Expect to pay anywhere from $500 to $1,500 (parts + labor) depending on the vehicle.
A good chunk of the expense is for labor as it can take a long time to access the necessary parts. Taxes and fees may increase the grand total.
Which Type of Rocker Arm to Buy?
Rocker arms are often made from stamped steel, which is basically flat sheet metal that was put through a stamping press and then shaped by a die. Steel is inexpensive while still being strong and fairly lightweight, and thus is a good option for economy cars.
High-performance vehicles usually use aluminum rocker arms, as they are much lighter. Truck engines often require even stronger rocker arms made from forged carbon steel or cast iron.
Some research is necessary to know which rocker arm to purchase if you are doing the job yourself. Automotive parts stores may stock the needed kit for your vehicle, or may be able to special-order parts.