How to Replace Rear Main Seal Chevy 350?

Chevy 350 engines are an old but truly unique piece of engineering. You have to be a true car lover to still have this 1967 beauty in your car. These engines can be proven pretty expensive to maintain especially the rear main seal of Chevy 350. The procedure of replacing the rear main seal of Chevy 350 requires removing a number of parts and the following are a complete set of instructions but this can save you around 1000$.

You must be an antique car lover for having an engine like Chevy 350 installed in your car. The classic sort of car that is nearly extinct in many developing countries.

Right now, the world is rocked by car companies like Tesla, Ferrari, Lamborghini, Ford, BMW, and other special-looking modern cars. Camaro and Mustang also got new designs and structures like modern cars.

But once the Chevy 350 was the most popular engine in the late 1970s and 1980s for Camaro and Corvette.

An engine like this requires a lot of attention. And we know that you are looking for how to replace rear main seal Chevy 350.

It’s not a difficult task even though Chevy 350 is an engine from 1967. So, let’s not waste one more second here and get to know how to replace 1 piece and 2 pieces of rear main seal Chevy 350.

What cars had a Chevy 350 engine?

As we have mentioned earlier that the Chevy 350 was launched in 1967. You could find it on any Camaro and Corvette cars you touch. The first car it got installed on was a 1967 Camaro.

From 1987 to 1992, the engine was used in a lot of Malibus, Pontiac Firebird, and Impalas cars.

And from the 1980s to the early 1990s, it was the most used engine for the Chevy Police Cruisers just like how the 1991 Caprice was.

It was a small block engine, but a powerful one. The stock car racers named it ‘Mighty Mouse’. 

How to replace rear main seal Chevy 350

Even though the Chevy 350 was released in the 1960s, it’s still one of the best small-block yet powerful engines out there. And we understand if you wanted to replace your current rear main seal with a new one due to a faster engine oil leak rate.

Replace rear main seal Chevy 350 Infographic

1 Piece Seal and 2 Piece Seal:

Before we delve into how to replace a rear main seal, here are a few surface-level talks. If your Chevy 350 has a 1 piece seal, then you have to remove the transmission section from the engine, but if you have a 2 piece seal, then you don’t have to remove it. That was the basic difference between the two seal types, all the other procedures are pretty much the same. In short, the 350 Chevy rear main seal replacement is easy and straightforward.

Following are the steps for the rear main seal replacement.

  • First, you need to remove the battery and starter. This can prevent you from getting an electric shock while working
  • If you have a single-piece, the Chevy 350 1 piece rear main seal replacement requires you to remove the transmission. But you can replace 2 piece rear main seal without removing engine transmission.
  • Now depending on the car transmission you may need to remove the flywheel and clutch plate for manual vehicles or flex plate for automatic vehicle
  • Now remove the bolts from the seal housing using a flat-head screw drive
  • Now remove the seal from the seal housing. Seal is usually fixed on its seat so you need to apply some force here
  • After removing the seal, clean the seal seat and the old seal itself
  • Place the old seal on the new seal, they have to be of the same size
  • Now cover the new seal with a thin layer of oil
  • Place the new seal in the seal seat.
  • Spray sealant spray on the seal
  • Replace the cover and all removed parts back on the engine and now you know how to remove rear main seal.

Chevy 350 Rear Main Seal replacement cost

Regarding the Chevy rear main seal replacement cost, the replacement isn’t something you can get done for cheap. Chevrolet items were always expensive, and the Chevy 350 wasn’t an exception.

The estimated cost of a rear main seal itself would be 30 US dollars to 120 US dollars but the replacement cost of the rear main seal of Chevy 350 would cost over 1300 US dollars. 

You can deduct the repair cost by replacing the seal all by yourself. Although it engages so much risk.

Is it worth replacing rear main seal?

If you experience excessive leakage of oil from your car and you kept running short on oil every time, then it’s necessary for you to replace your damaged 350 Chevy rear main seal.

We are aware that the cost of replacing a rear main seal is pretty expensive. But when you look at the bigger picture, you will notice that you have to buy oil more than ever due to the faster oil draining rate.

Sometimes, you could get them for a cheaper price but sometimes you may go bankrupt buying only oil for your Chevrolet car.

So, now you should reconsider whatever your opinion was on: Is it worth replacing rear main seal?


A damaged Chevy 350 rear main seal can be a real pain in the back, but replacing the rear main seal could be more painful.

Either way, we are destined to spend a lot of money on this. At least our guide on how to replace the rear main seal Chevy 350 will help you minus about 1000 US dollars.

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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news

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Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at with a passion for the automotive industry.