Why does a crankshaft pulley break?

Asked By: Onkar Gayarre | Last Updated: 23rd April, 2020
Category: automotive auto parts
4.8/5 (1,379 Views . 12 Votes)
It is connected to the crankshaft on the engine and reduces vibrations that originate from your engine. In addition, it serves as a pulley for the drive belts. This resonance causes too much stress for the crankshaft. If this stress continues, the crankshaft will break and your vehicle will be inoperable.

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Similarly, you may ask, why would a crankshaft pulley break?

When an engine has a bearing failure, the excessive clearance can cause the crank to have a “jump rope” effect inside the engine. The crankshaft can bend severely or even break in some cases. In cases where a nitrided crankshaft is bent, it is usually not recommended to straighten.

Secondly, does the crankshaft pulley move? The camshaft and crankshaft pulleys are directly attached to the engine (camshaft and crankshaft) and will only rotate if the engine is running or manually rotating the engine by placing a socket and breaker bar to the crankshaft pulley bolt.

Just so, how do I know if my crankshaft pulley is bad?

Bad Crankshaft Pulley Symptoms

  1. 1) Engine Vibrations. The first symptom that will likely come up are engine vibrations.
  2. 2) Alternator Failure. The crankshaft pulley is responsible for powering the alternator.
  3. 3) Power Steering Pump Failure.
  4. 4) Transmission Damage.
  5. 5) Irregular Idle Engine Speed.

How do you know if your crankshaft is broken?

Symptoms of a Bad Crankshaft Position Sensor

  1. Your “Check Engine” Light is Blinking.
  2. It's Difficult to Get Your Vehicle to Start.
  3. Your Vehicle is Stalling and/or Backfiring.
  4. The Engine is Making Your Vehicle Vibrate.

39 Related Question Answers Found

Can a crankshaft be repaired?

Nick Boes of Shaftech in Fostoria, Ohio, emphasized how repairing a crank can take less time than replacing it. “The lead times for most new crankshafts are approaching 12 weeks in most cases, which is the better part of most racing seasons. Repairing a crankshaft may be less costly and faster than racers think.

How do you remove crankshaft pulley?

Disassemble the crankshaft pulley
You just have to place one end on the bolt-removing tool and slacken the bolt using an impact wrench. With the bolts included in your tool, you may now tighten the bolt remover tool. Keep doing this step until the crankshaft pulley is finally released.

What does a crankshaft pulley look like?

Definition. A crankshaft pulley, also called a harmonic balance wheel or crankshaft sheave, is a grooved, wheel-shaped device that connects directly to the vehicle's crankshaft. The crankshaft essentially converts the linear, or straight, movement of pistons into a rotational motion.

What causes crankshaft damage?

Insufficient lubrication can cause bearings in the crankshaft to fail. An over pressurized cylinder occurs when the crankshaft's liner has a coolant leak. The pressure causes the crankshaft to slip or bend. Cracks most commonly occur at the fillet between the journal and the web on the crankshaft.

Is crankshaft pulley and harmonic balancer the same thing?


A harmonic balancer is a front end accessory drive component that is connected to the crankshaft of an engine. Harmonic balancers do have many names, though, such as damper, crankshaft pulley and crankshaft balancer, among others.

Can you drive with a broken crankshaft?

Yes. It's called a "driver". If that safety system overrides itself, well then, the car is pretty vulnerable. Yes a car can run with a broken crank, sometimes; if the crank is broken in such a way that the pieces still force each other to rotate.

How do you fix a pulley?

Part 1 of 1: Replacing an idler pulley
  1. Materials Needed. Replacement idler pulley.
  2. Step 1: Disconnect the battery. Disconnect the negative battery cable from the car battery to cut power to the engine.
  3. Step 2: Remove the drive belt.
  4. Step 3: Remove the old pulley.
  5. Step 4: Install the new pulley.
  6. Step 5: Torque the pulley.

What does a crankshaft pulley do?

The crankshaft pulley (harmonic balancer) is mounted on the end of the crankshaft. Its purpose is to turn the drive belts that operate the engine accessories (alternator, air conditioning compressor, etc.)

Where is the crankshaft pulley?

The crankshaft pulley is bolted to the harmonic balancer and turns the belt, or belts, to operate other engine components like the alternator or air conditioning compressor. It is located at the end of the crankshaft near the bottom of the engine.

How much is a crankshaft pulley?


Prices for most OEM crankshaft pulley replacements should hover around $100 - $250, and it should only go higher if you're getting a high-performance replacement that's designed for racing applications.

Can you fix a harmonic balancer?

It is not due to the seal being faulty. Instead, the groove allows for oil to migrate out. The good news is, the harmonic balancer can easily be repaired with a kit that usually retails for under $10.

What happens when harmonic balancer fails?

Engine vibration
If the harmonic balancer gets too old or fails and can no longer properly absorb the harmonic vibrations, the engine will shake excessively. The shaking will become even more pronounced, and therefore dangerous to the engine at high speeds.

How does a harmonic balancer go bad?

Over time, the crankshaft harmonic balancer can go bad from constant exposure to chemicals, the elements, or from old age. Signs that your crankshaft harmonic balancer needs to be replaced include: The engine is loud and you feel vibrations coming from your engine.

Can you weld a harmonic balancer?

Hello - No, welding the harmonic balancer to the crankshaft is not a good idea for at least 2 reasons. Welding the hub to the crank will almost certainly pass enough heat to the rubber portion of the balancer to damage it.

Can you drive with a bad crankshaft pulley?


Indeed, if it's the crank pulley and the harmonic balancer comes off with it and the engine continues to run that can damage the crankshaft. That would be very bad. Other pulleys could get distorted if a fastener is missing and in such condition could damage the drive belt riding on the pulley.

How do you remove a crankshaft from an engine?

How to Remove a Crankshaft From Under the Car
  1. Remove the engine's belts.
  2. Remove the pulley which attaches to the harmonic balancer.
  3. Remove the harmonic balancer.
  4. Drain the radiator by removing the radiator's drain plug.
  5. Remove the water pump.
  6. Remove the timing chain cover.
  7. Remove the timing chain.
  8. Remove the oil pan.

How do I know if I need a new harmonic balancer?

Signs that your crankshaft harmonic balancer needs to be replaced include:
  1. The engine is loud and you feel vibrations coming from your engine.
  2. The pulley belt may slip causing your vehicle to backfire or misfire.
  3. The vehicle's ignition timing will be off.
  4. The vehicle will not start at all.