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How to Replace Rear Main Seal Chevy 350

The rear main seal on a Chevy 350 engine is a critical component that helps to prevent oil leaks and maintain engine performance. Over time, the seal can wear out and begin to leak oil, which can cause damage to the engine if left unchecked. In this article, we will explore how to replace the rear main seal on a Chevy 350 engine.

Symptoms of a Bad Rear Main Seal on Chevy 350

If you suspect that your Chevy 350 engine has a bad rear main seal, there are several symptoms to watch for, including:

  • Oil leaks from the rear of the engine
  • Low oil pressure
  • Engine smoking or burning oil
  • Unusual engine noises, such as knocking or ticking

Tools Needed for Replacing Rear Main Seal on Chevy 350

  • Socket set
  • Torque wrench
  • Pry bar
  • Screwdriver
  • Oil pan gasket
  • Rear main seal installation tool

Steps to Replace Rear Main Seal on Chevy 350

  1. Disconnect the negative battery cable and drain the engine oil.
  2. Remove the transmission and flywheel from the engine.
  3. Use a pry bar to remove the old rear main seal from the engine block.
  4. Clean the sealing surface on the engine block and install the new rear main seal using a rear main seal installation tool.
  5. Install a new oil pan gasket and reattach the oil pan.
  6. Reinstall the flywheel and transmission.
  7. Refill the engine with oil and reconnect the battery cable.

How hard is it to change a rear main seal?

Changing a rear main seal can be a difficult and time-consuming task, especially for those who are not experienced with automotive repairs. The process usually involves removing the transmission and flywheel from the engine to gain access to the rear main seal, which can be challenging for those without the proper tools or knowledge. Additionally, it’s important to take care when installing the new seal to ensure that it is properly seated and doesn’t leak oil.

However, with patience and attention to detail, it is possible for those with some mechanical knowledge to successfully change a rear main seal themselves. It’s important to weigh the time and effort required versus the cost of having a professional do the job to determine the best course of action.

How often should I replace the rear main seal on my Chevy 350 engine?

It’s recommended to replace the rear main seal on a Chevy 350 engine every 100,000 miles or sooner if you notice any symptoms of a bad seal.

Can I replace the rear main seal without removing the engine from the vehicle?

While it is possible to replace the rear main seal without removing the engine, it can be difficult and time-consuming. It’s usually easier to remove the engine from the vehicle to replace the seal.

How much does it cost to replace the rear main seal on a Chevy 350 engine?

The cost of replacing the rear main seal on a Chevy 350 engine can vary depending on the labor rates in your area and the cost of the parts. It’s generally a good idea to budget for around $500-$1000 for parts and labor.


Replacing the rear main seal on a Chevy 350 engine can be a daunting task, but with the right tools and knowledge, it can be done at home. It’s important to watch for symptoms of a bad seal and replace it as soon as possible to prevent damage to the engine. By following the steps outlined in this article and taking the time to do the job correctly, you can ensure that your engine stays in good working order for years to come.

Rachael McAdams

I'm Rachael, CEO of AutoGeeX, bring unrivaled expertise and passion to the automotive industry. With extensive knowledge and a deep understanding of cars, she shares captivating tales, invaluable insights, and practical tips with readers. As an active presence in the car community, Rachael ignites excitement, revolutionizing the automotive landscape with AutoGeeX's pursuit of perfection.

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