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What are the Symptoms of a Bad Camshaft? 6 Signs to Watch Out For

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The camshaft is rarely to blame when it fails. It’s usually worn timing gear, broken dowel pins, or mechanical interference in the valve train which causes it to malfunction. However, there are cases where this part simply fails from metal fatigue. To help you determine when this part might be bad, we’ve listed down the common signs of a bad camshaft.

6 Symptoms of a Bad Camshaft

When ignored, a busted camshaft may also cause extensive damage to some parts of the engine like the crankshaft and cylinder head.

Close up look of camshaft in white background
The camshaft is rarely to blame when it fails. It’s usually worn timing gear, broken dowel pins, or mechanical interference in the valve train which causes it to malfunction.

To help you prevent all of this, here are common camshaft wear symptoms to look out for:

  • Active check engine light
  • Loud ticking or tapping sounds
  • Metal debris in the engine oil
  • Cylinder misfire
  • Increased emissions as a result of misfiring
  • Visible signs of damage

Active Check Engine Light

The check engine light comes on whenever your vehicle’s computer detects a potential problem that may lead to an increase in emissions. This warning light can be triggered by multiple things, so you’ll need to connect your vehicle to an OBD scan tool to check what codes are stored. This serves as the first step in any engine performance diagnostic strategy.

Active Check Engine Light blinking
The check engine light comes on whenever your vehicle’s computer detects a potential problem that may lead to an increase in emissions.

Loud Ticking or Tapping Sounds

If you’re wondering what a bad camshaft sounds like, it usually makes loud ticking or tapping noises. As it starts to fail, you may notice odd sounds coming from your vehicle’s valvetrain.  Ticking noises are often linked to worn cam lobes. However, identifying the source of these sounds can be tricky as they are often intermittent.

Metal Debris in the Engine Oil

A worn camshaft lobe can result in metal debris circulating through the engine. Although you might not see the metal on the dipstick, there may be debris or metallic swirls in the oil after you drain it.

Cylinder Misfire

A vehicle with a damaged camshaft may suffer from reduced engine performance due to cylinder misfire. Your vehicle may hesitate and lose power, jerk or shake aggressively, consume more fuel than usual, and produce more emissions.

Increased Emissions as a Result of Misfiring

A worn camshaft can lead to an engine misfire, which in turn, causes an increase in tailpipe emissions.

Visible Signs of Damage

If your car has an OHC (overhead camshaft engine), lifting the cam cover will show you if your camshaft has any visible signs of damage. Look for issues such as worn lobes or scored journals that could indicate an internal failure that has damaged the camshaft. 

What Is a Camshaft?

A camshaft is a cast iron or hardened steel rod with round bulges called lobes. It is a crucial component in your engine, directly responsible for the volume of air and fuel that flows into the combustion chamber and the exhaust gases it expels in time for the next cycle or charge.

Camshafts and valve in oil on the car engine
A camshaft is a cast iron or hardened steel rod with round bulges called lobes.

The camshaft rotates, with the pointy ends of the lobes coming into contact with the cam followers or valve lifters, which push the valves to open at exact times throughout the cycle. It precisely actuates these valve lifters, coordinating these valve motions with the pistons’ movement in each cylinder and the firing of the spark plugs. Depending on your vehicle’s engine type, you may have one, two, or four camshafts.

What Happens When a Camshaft Breaks?

When a camshaft breaks, the components around it are also at risk of damage. The parts most vulnerable to damage are those located inside of your vehicle’s engine. These include the other valvetrain components, the crankshaft, cylinder block, cylinder head, pistons, and connecting rods.

A damaged camshaft can snap in two because of a crack or fracture caused by rough handling during shipping or some time before installation. If the camshaft is defective, it may appear bent. The cam can also chip or break off entirely after being hit by any of the engine’s rotating parts that may have come loose.

camshaft and valve springs in a tray
When a camshaft breaks, the components around it are also at risk of damage.

What to Do If You Have a Bad Camshaft

If you’re not a professional, it would be best to leave camshaft repairs to a mechanic. This is due to the extent of diagnosis needed before deciding on the best way to fix this problem. What you might have thought to be a completely damaged camshaft may be something else entirely.

Depending on the extent of wear, there are two options for fixing your damaged camshaft:

  • Replace your camshaft with a new one
  • Have your old camshaft machined

In terms of costs, buying a new camshaft is the most expensive option. A remanufactured camshaft costs less, while machining your camshaft (if it’s still usable) should be even cheaper since you’re supplying your camshaft to use as the core.

A camshaft replacement can go for anywhere between $50 and $300 plus labor costs. The price varies depending on the camshaft’s brand and condition. Depending on the severity of the damage, other related repairs may also be needed.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic.

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