What Causes Bent Push Rods? 7 Reasons

A bent pushrod can severely impact the functioning of your car engine. But what causes bent push rods? Let’s find out.

It is no new information that the engine is the most important unit of your car. If there is any kind of problem with the engine, it is going to affect the working of the rest of your car. One of these components that can cause an engine issue is pushrods. 

These are small metal rods that function with the valve of a car engine, making sure the fuel intake by the engine is managed. But what should you do if there is a problem with the pushrods? Read on to find out. 

What Causes Bent Push Rods

What Is A Push Rod, And Why Is It Important?

A pushrod is a metal rod that is part of the overhead engine valve that is operated by a camshaft. This is a simple yet effective component that is used in valve engines and is one of the more inexpensive car components available. 

The function of a pushrod is to transfer motion from a camshaft to the valve, and it is inserted into the engine block. This rod runs through a series of plates which help to keep the pushrod aligned with the valves. It works like a rocker arm that opens and closes the valves of the engine. 

The pushrod is a hollow structure made from aluminum or steel — the dimensions of the average rod range between 5/16 to 3/8 inches. The size will depend on the design of the engine, but it will normally be somewhere between 6 and 8 inches. 

What Happens In A Bent Push Rod?

When the pushrod gets bent, there will be a significant delay in opening and closing the valve in the engine. This is because with the wearing out of the rod or any kind of damage, the pushrod will not slide freely, which will, in turn, affect the valve. 

There can be a number of reasons for the pushrod in an engine to be bent. It will start by decreasing the performance of your car’s engine, increasing fuel consumption, and causing damage to the surrounding components of the engine. 

What Causes Bent Push Rods

How Can A Bent Push Rod Occur?

Here are the most common reasons that your pushrod may be bent:

Wearing out over time

Before anything else, the pushrods are metal tubes that are attached to other components of the engine. Metal parts will wear out over time as they continue to rub against each other with motion. The friction caused due to the wear out can cause overheating and tears which damages the rods. 

If the wear and tear and not checked out early and the engine continues to put pressure on the parts, there is a chance for more damage. 

Overheating of the engine

In overhead valve engines, overheating can cause the metal in pushrods to expand. This will eventually lead to misalignment of the whole structure and damage to the valves. The first sign of this happening is when the engine starts misfiring and eventually gets damaged if left unchecked.
One way to avoid this problem is to keep the engine coolant level in check and not allow the engine to overheat. Try turning off the engine as soon as you see signs of overheating. 

Loose valve guides

A broken valve or loose valve guides result in the pushrods bending. When the valve guides are loose, they cannot contain the valves as they open and close. The disturbance of the valves can put pressure on the pushrods since they are constantly attached to one another. 

Pushrods are hollow metal rods that can actually be bent with any kind of little force on the rod. If there is pressure on the longitudinal axis, it will be bent and has to be replaced.  

Rocker arm getting loose

In overhead engines, pushrods transfer the motion from the camshafts to valves. The rocker arm is the main component that operates the valves, acting as a lever to open and close them.
When this rocker arm gets loose, the valves can start bouncing off the main path, and the pressure of this movement can bend the pushrods. In this case, the rod will not be able to transfer the required motion to the valves, which will cause the engine to consume more power. 

Sticking the hydraulic lifters

Sticking hydraulic lifters can be a major cause of pushrods being bent. These lifters are used in engines to improve the efficiencies of valves, and they work by adjusting the clearance by using oil pressure between the rocker arm and valve.
If these hydraulic lifters get stuck and you end up applying too much force to release them, they can bend the pushrods in turn. This is also one major cause of engine misfires and damaged valves. 

Incorrect installation of the pushrods

A common cause of pushrods getting bent frequently is incorrect installation. If the rocket arms are not properly torqued down, or there is some fault in the surrounding components, they can put excess pressure on the rods. Over time, this pressure will cause the rods to bend and result in engine problems. 

Damage due to accidents

If there has been an accident with the vehicle or the engine has been hit suddenly by some strong force, it can damage the pushrods. This can also happen if there is some kind of foreign object stuck in the engine that is affecting the other components. This is when you have to take it to a mechanic to be inspected closely. 

Additionally, if you are using rods that are made from weak materials, you run the risk of damaged pushrods that will easily bend. 

What Causes Bent Push Rods

What Are The Symptoms Of A Bent Push Rod?

Whenever there is some kind of problem with the pushrod, especially if it is bent for some reason, there are a number of symptoms that start showing in your car. These are some of the signs you should look out for. 

Ticking Noise

If there is a bent pushrod in your car, you might hear repeated ticking noises from the engine. This noise can be caused either by some kind of damage in the pushrod or worn-out rocker arms. 

When the pushrod is bent, the engine starts making a rocking sound. In case of wear out of the rocker arms, the valves do not open and close smoothly, so the noise made is different from usual. In either case, it sounds like a ticking coming from the engine. 

Rough Idling

In a car, rough idling is an occurrence when you start your car and keep it running without shifting gears or hitting the gas pedals. If it starts occurring without you starting up the engine, it is a sign that the engine is in some kind of trouble. 

If you have a bent pushrod, there might be problems with the valve opening and closing. This can cause the engine to malfunction. 

Engine Misfiring

Engine misfiring is one of the basic symptoms of a bent pushrod. When the valve is not opening and closing correctly, it can cause the fuel mixture to enter the cylinder at the wrong time, which can cause a misfire. 

Make sure that you have ruled out the potential causes of an engine misfire, like a fault in the ignition system, fuel injector, or even a faulty spark plug. Once you have checked these out, try to sort out the bent pushrod problem. 

Failed Compression Test

When a pushrod gets bent, it is not able to transfer the power from the camshaft to the valves, so the valves will not open all the way. The failure of the valves causes a drop in the air levels in the combustion chamber, so the compression ratio of the engine becomes low. 

As a result of the compression decreasing, the engine will not have as much power to generate. This can be checked by a compression test, where you have to check the compression readings of your engine. If it is low on one side, it might be time to check for a bent pushrod. 

Increase In Emission 

A bent pushrod might be the reason that there is an increase in the emission levels of your car. When the fuel/air mixture in your car is not able to burn properly, the residual fuel will also be expelled from the exhaust. Higher than normal emissions can be a symptom of your pushrod having an issue. 

Poor Acceleration Performance 

If your car’s performance has suddenly gone down and there is not enough power generated on acceleration, you can trace the problem back to a bent pushrod. The pushrod will not be able to transfer the required amount of power to the engine, which helps in acceleration. 

If you are putting the accelerator but notice a significant drop in the performance of your car, you should check for the pushrod and whether there is wear out in the valves involved. 

What Causes Bent Push Rods

How To Prevent This Problem?

There are a number of things you can do to prevent a pushrod from being bent:

  1. Change the engine oil timely

Changing your engine oil is mandatory to avoid friction between the metal parts of a car. If the engine is kept lubricated, the metal-to-metal contact is reduced, and the push rods will also avoid too much friction and not be bent over time. 

  1. Reduce the engine vibrations

Vibrations in cars can become one of the leading causes of a bent pushrod. This can be done by using balanced weights on the car, installing engine mounts, and adding damping material to the bay of the engine

  1. Go for high-quality pushrods

Pushrods are fairly inexpensive compared to other automobile parts. So if you are purchasing new ones to replace any damaged rods, make sure to purchase the best one available. The ones with better quality will ensure that it doesn’t break under pressure. 

  1. Make sure to install the pushrods correctly

Installing a pushrod in a car makes sure that it will not get bent or damaged if they are under any excess pressure. The rods should also stay in place to help in the opening and closing of the valves in the engine. 

  1. Avoid excessive stress on the rods 

Try not to put too much pressure on the pushrods by avoiding hard starts and sudden stops. This helps not to overload the engine and keep the rods intact for longer. 

 

These are just safety measures that can help you out with the care of your car components without seeking professional help every time.

Replacing A Bent Push Rod

If there is a bent pushrod issue in your car, the only option you have is to replace it. Since it is a fairly difficult task in car maintenance involving the replacement of a component in the combustion engine by opening up the parts. This is why the best idea is to take your car to the mechanic when you run into this problem. 

The average cost of replacing a pushrod can be anywhere between $800 and $1200. It can get more expensive if some of the important surrounding components have been damaged due to the wear and tear of the rods. 

There are a few common expenses incurred in the replacement of a pushrod. This will involve the price of the main pushrod and additional components, which is often called a pushrod replacement kit. It includes components like rocker arms, pins, a new valve cover, gasket, and seals which will cost between $350 and $500. 

With the amount of work involved in replacing the pushrod, you have to consult an experienced mechanic. The labor charge will be an additional charge for the entire task, but it will ensure that it is a job well done and your car’s engine will function efficiently after the replacement. 

What Causes Bent Push Rods

Frequently Asked Questions

How long do push rods last?

Pushrods have an average lifespan of five to seven years, which range between 50,000 to 70,000 miles. How long the pushrods will last will also depend on their quality, what model your car is and how you have maintained it over the years. 

Do push rods wear out?

Yes, pushrods can bend out over time due to the pressure that the rod is carrying with regular functioning. It can also occur due to maintenance issues, accidental damage, or any kind of problem with the valves. 

What is wrong with push-rod engines?

The pushrods are actually the main problem of pushrod engines. They have rocker arms that work with the rods to open and close the valves in the engine. These pushrods, once bent, can reduce the performance of the engine by a huge margin. They can also be an expensive replacement cost. 

Why do my pushrods keep bending?

In a diesel engine or petrol engine, hydraulic lifters or gaps between the rod and lifter can become the main reasons for repeated bending of the pushrods. The rods can also bend due to loosening valve thimbles or wearing out of rocker arms. 

Conclusion

Your main priority should be to maintain your engine regularly so that you can figure out the first sign of damage. Replacing the pushrods in your engine can be a complicated and expensive task, so make sure you take preventive measures before the rods are bent before their expiry dates. 

We hope this article helps you out when there is an emergency with your engine. Thank you for reading!

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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