How to replace the crankshaft oil seal
Auto repair

How to replace the crankshaft oil seal

09.11.2022 /

Engine oil leakage is prevented by the crankshaft oil seal. Replacing requires several tools such as a hammerless hammer and a band wrench.

The purpose of the crankshaft seal is to divert oil back to the oil sump or oil pan to maintain the proper oil level and prevent it from leaking to the ground. Your engine has two crank seals; one seal is located at the front of the engine, behind the crankshaft balancer, and the other at the rear of the engine, behind the flywheel.

This article will discuss how to replace the front crankshaft oil seal. Although the steps below are the same for most engines, there are many different engine designs, so please refer to the factory service manual for detailed instructions for your specific vehicle.

Part 1 of 1: Replacing the front crankshaft oil seal

Necessary materials

  • Breaker (1/2" drive)
  • Combination wrench set
  • Hammer with a dead blow
  • Paul Jack
  • Gear puller to match the design of your harmonic balancer
  • Jack stands
  • New front crankshaft seal
  • Screwdriver Set
  • Seal removal and installation kit
  • Socket set (1/2" drive)
  • Tape key
  • Torque wrench (1/2" drive)

Step 1: Prepare the car. Jack up the vehicle high enough to access the harmonic balancer located at the front of the engine and attached to the crankshaft. Fix it on jacks.

Step 2 Remove the accessory drive belts.. Many modern vehicles have an automatic spring-loaded belt tensioner that can be rotated to loosen the belts.

Depending on the design, you may need an open end wrench or ratchet. In older vehicles, and even some newer ones, the mechanical tensioner needs to be loosened.

  • Functions: Take a photo of the belt pad for future reference.

Step 3: Remove the harmonic balancer bolt.. Remove the harmonic balancer bolt using a strap wrench to hold the balancer still while loosening the bolt with a socket and ratchet or broken bar. It will be very tight, so pull hard.

Step 4: Remove the harmonic balancer. Use a puller to remove the harmonic balancer. Place the hooks in an area that is not easy to break, such as the edge of a pulley.

Some vehicles have threaded bolt holes in the balancer that can be used to attach a puller. Tighten the center bolt with a ratchet or a broken bar until the balance bar is free.

  • Functions: Most harmonic balancers are kept from rotating on the crankshaft by a key. Don't lose your tree key as you will need it for reassembly.

Step 5: Remove the old crankshaft oil seal.. Using a puller, carefully remove the old seal from the crankcase.

The goal is to try and get hold of the seal between the seal and the crankshaft and release it. It may take several tries in different positions to completely release the seal.

Step 6: Install a new crankshaft oil seal.. Lubricate the new seal with fresh engine oil to prevent seal failure and facilitate installation. Then position the seal with the lip towards the cylinder block and push it in by hand.

Place the seal on the crankshaft using a seal crimping tool and use a non-hammer hammer to gently tap the seal into place.

  • AttentionNote: You can also use a large deep flare socket or pipe socket as the seal driver, as long as it has the same outside diameter as the seal itself.

Check that the new crankshaft seal appears to be properly installed.

Step 7: Install a New Harmonic Balancer. Align the keyway in the new balancer with the key for the key, and carefully slide the balancer onto the crankshaft, making sure the keyway remains in the correct position.

Install the center bolt and tighten until the correct torque is reached.

Step 8: Reinstall the straps. Turn or loosen the belt tensioner to reinstall the removed belts.

  • Attention: Refer to any photos you have taken or the factory service manual to determine the correct belt routing.

Step 9: Lower the car. With the vehicle under floor jack, carefully remove the jack stands and lower the vehicle. Start the car to ensure proper assembly and operation.

Replacing the crankshaft oil seal is doable if you follow the right steps. However, if you are not comfortable doing such a task yourself, a certified technician from AvtoTachki, for example, will have the tools and skills needed to replace the front crankshaft oil seal for you.

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