Bad Valve Spring Symptoms – How To Tell A Broken Valve Spring

Valve springs play an important role in the operation of your engine’s valves. Once they begin to fail, it can lead to various issues.

Thus, it is essential to know the bad valve spring symptoms so you can act quickly and avoid further damage.

Luckily, we have gathered a list for you in this article to help you maintain the vehicle’s normal operation.

What Do Valves Spring Do, And How Do They Work?

bad valve spring symptoms
How Do Valves Spring Work

What They Do

The valvetrain system of an engine bay depends heavily on valve springs. In essence, the proper function of valve springs is to maintain the closed position of the valves.

The camshaft lobe must overcome the car’s spring load each time the valve is opened since the valves are constantly spring-loaded to the closed position.

The ideal valve spring combines strength with flexibility to consistently open and close the valve while absorbing shock and vibration from the engine.

They are typically composed of high-strength steel and are available in many sizes and forms to accommodate various engines and applications.

How They Work

When the camshaft rotates, it pushes on the rocker arm, pushing down on the valve stem and opening the valve. Once the camshaft lobe has passed, the spring returns the valve to its closed position.

The spring’s function is to store energy when compressed and release it when the camshaft lobe has moved past, which closes the valve.

As the valve lift and opening duration depend on the camshaft design, valve springs must match the engine’s camshaft profile.

Suppose they are too weak; the valves won’t close properly, leading to poor engine performance or severe damage.

On the other hand, if they are too strong, they can cause signs of wear and tear on the valvetrain and increase the risk of valve float at high RPMs (revolutions per minute).

What Are Some Bad Valve Spring Symptoms?

symptoms of bad valve springs
The Symptoms Of Bad Valve Spring

Some Ford 6.2 broken valve spring symptoms include: power loss at high RPM or at any speed, rattling, strange sounds, engine warning light turning on, rough engine, and backfires or misfires.

Loss Of Power At High RPM

Engines run at high speeds, turning between 600 and 800 RPM at idle and up to over the 6,000 rpm range.

The camshaft will rotate at around half the crankshaft’s maximum speed when the engine runs at high revs.

Engines with brittle valve springs may have issues at high RPM.

In case your car has a defective valve seal before the subsequent combustion cycle, your cylinders might lose compression, possibly even resulting in an engine misfire. This is called valve float.

When the bad valves cannot maintain pace with the engine’s speeds, valve float essentially occurs. Also, if you have trouble with a high RPM range when starting the car, check out this guide.

Loss Of Power At High Engine Speed

A broken valve spring will have problems when the engine speed increases, and you will feel a lack of acceleration power.

Not only does a fractured valve reduce engine power and performance, but it can also seriously harm the engine, necessitating expensive repairs (maybe thousands of dollars).

Suppose the valve springs are weak; the valve may open when the piston climbs the cylinder during the compression stroke.

On occasion, the piston may even make direct contact with the valve. The valve can potentially bend due to this contact. The piston may even break in some circumstances.


Valve covers are where you’ll most likely hear rattling. There is a broken-off portion of the spring that is bouncing around the head of the cylinder, which is what is causing the rattling.

Yet even if the spring split in two, it needn’t be the case. Once more, a slight rattle is not a telltale sign of a bad spring.

Unusual Noises

If you leave it running like that, the engine will quickly self-destruct, making a loud knocking noise that is impossible to ignore.

This is due to the banging being brought on by a valve that fell into the cylinder and is currently being slammed against the cylinder head by the piston.

Hence, when you hear excessive valve noise (knocking, stop the engine right away and don’t start it until you’ve had the engine bay inspected to ensure quiet operation.

Illuminate Engine Warning Light

The check engine light will most likely come on when something is wrong with your car. Still, it is nearly impossible to diagnose a faulty spring using an OBD2 reader.

This is because misfire codes are returned since no procedures are in place to designate a valve spring. Yet, based on the failure code, you can identify the particular cylinder with a damaged valve spring.

Rough Engine

The poor performance occurs in an automobile engine running with a damaged valve spring at rough idle speeds.

When such is the case, the engine will tremble, backfire, and make a strange sound, similar to an air pump.

The main reason is that one cylinder is largely inoperative and a waste of space.

But once more, unless you experience over two of these signs of bad valves, you won’t be able to say with certainty whether the valve spring is to blame.

Backfires Or Misfires

The sole inevitable sign of a bad valve spring is a backfire and ignition misfire. When your spring snaps, the air-fuel mixture remains in the engine’s exhaust and intake manifold when your spark plug fires.

It implies that both the exhaust and the intake can lead to backfire

Misfires and backfires are ambiguous weak valve spring symptoms that are insufficient to conclusively diagnose anything. Learn more about misfire on 2 cylinders here.

What Happens If Your Car Has Broken Valve Spring Symptoms?

broken valve spring symptoms
If Your Car Has Broken Valve Spring Things Can Happen

Many performance and drivability issues in an engine can be brought on by damaged or weak valve springs.

Malfunction valve springs can seriously harm an internal engine, generate engine noise, and result in compression loss.

Often, the most catastrophic repercussion is not the actual breakage of the valve springs but the damage resulting from actions taken after the breaking.

When a spring snaps, it can just give way enough for the valve to fall into the cylinder and possibly be struck by the piston.

Furthermore, the valve stem keepers or locks may let go of the valve and enable it to fall into the cylinder, severely damaging the cylinder head, piston, and other adjoining components.

How To Check For Bad Valves (Diagnosis)

You require a compression tester to determine whether your engine’s valve spring is broken.

So, normally, all your cylinders will display low compression issues if your engine has a burst cylinder head gasket or worn piston rings.

Step 1: Locate the main ignition fuse or ignition module using the owner’s manual and take it out.

Step 2: Put the compression tester in place after removing the electrical spark plug from one cylinder.

Step 3: Check the compression on your tester by turning the engine over for a few seconds.

Step 4: Repetition of the procedure will reveal that any cylinder with no compression has a faulty valve spring.

Frequently Asked Questions

Can Valve Springs Increase Horsepower?

No. A valve spring does not increase horsepower. In actuality, the horsepower loss caused by valve springs is due to the requirement for the engine to overcome them each time a valve is opened.

For instance, a motor without springs that uses a desmodromic valve system can produce up to 30% more horsepower.

How Often Should I Replace My Valve Springs?

There is no fixed maintenance schedule for valve springs, so they are often replaced as you go along when you service the car’s head gasket or do another significant top-end repair.

But because damaged valve springs may completely wreck an engine, it’s a good idea to check them up at the 100,000-150,000-mile mark.

How Much Does It Cost To Replace A Valve Spring?

On average, the replacement cost is around 220 to 330 dollars, including labor. Still, the price can change depending on many factors, such as the valve quality, valve quantity, the facility you go to, etc.

The Bottom Line

Bad valve spring symptoms can be frustrating and concerning for any vehicle owner.

However, by understanding the signs of broken springs and taking action early, you can prevent more serious engine damage, maintain your correct valve operation, and avoid costly repairs down the road.

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