Crankcase Breather Maintenance – Diesel Engine: Why does it leak?

Products 2022.02.18
Crankcase Breather Maintenance - Diesel Engine Why does it leak - Banner

What is Crankcase Breather?

Crankcase Breather

Crankcase breather is also known as crankcase oil separator or crankcase ventilation. As its name, the function of the oil separator filter is to clean the oil mist from the engine crankcase.

We all know when the diesel engine works, it causes pollution, not only to the environment but also to human bodies, this tells how important a crankcase breather is.

What does an oil separator do?

An oil separator is a device that separates oil from the air that enters the engine. Oil is necessary for lubricating the moving parts of the engine, but it can also cause problems if it mixes with the air.

Oil can contaminate the air intake system, reduce the efficiency of the combustion process, increase the emissions of harmful gases, and damage the catalytic converter. An oil separator prevents these issues by filtering out the oil from the air and returning it to the oil pan.

What is an oil separator gasket?

An oil separator gasket is a seal that fits between the oil separator and the engine block. It prevents oil leaks and ensures a tight connection between the two components. An oil separator cover gasket is usually made of rubber or metal and can withstand high temperatures and pressures.

Over time, however, an oil separator gasket can wear out, crack, or break due to exposure to heat, vibration, and corrosion. When this happens, it can cause oil leaks, poor engine performance, and increased emissions.

Understanding Product 20532891, a Volvo/Mack truck gasket

One of the most popular and reliable oil separator gaskets on the market is the Volvo/Mack 20532891 Oil Separator Gasket for D12/D13 Engine. This gasket is designed for Volvo/Mack trucks and is compatible with various models such as DD12,DD13, and more. The Product is made of high-quality materials and has a durable design that can withstand harsh conditions. It also has a precise fit that ensures a leak-free seal and easy installation.

Why does the crankcase breather leak?

The crankcase breather should be maintained regularly in a proper way or it might cause some leaking problems.

What are leaking problems you might face?

  • Leak from the hose of the crankcase breather filter. –If you do not maintain and clean the crankcase breather when the engine reaches a certain mileage, the oil will leak from the crankcase breather hose.
  • Leak from the mating surface of the crankcase breather and the engine. –If you do not use a new gasket for the side between the crankcase breather and engine block while you maintain the crankcase breather or you do not use a gasket with the correct and high-quality material, it could also cause leaking.

What do you need to do when you maintain the crankcase breather?

When maintaining the crankcase breather, not only to clean the filter inside, it is also important to replace the gaskets. When you open the crankcase breather, you can see the seals inside with the fuel and oil. After cleaning the grooves, it is important to use new gaskets, this would make the crankcase breather not leak again.

Where can you purchase crankcase breather repair gasket kits with aftermarket price and OE-quality?

Are you looking for aftermarket crankcase oil separator seals or seal kits, at the same time, you hope the products you get are OE-level quality? That’s what we offer, check out the items below.

Gaskets/ gasket repair sets for crankcase breather for Heavy-duty diesel engines – Volvo, Detroit Diesel, Navistar, John Deere


Detroit Diesel


John Deere

Gaskets for mating surface

Gaskets for the mating surface of the crankcase breather to the engine block.



John Deere


MJ Gasket is currently seeking those who are in need of heavy-duty engine gaskets and seals.

MJ Gasket has over 40 years of experience in manufacturing heavy-duty engine gaskets. Through continuous development and improvement of their technology, they have produced high-quality gaskets that have become a promising product in the market. MJ Gasket has assisted countless repair shops in expanding their businesses by providing them with high-quality gaskets.

MJ Gasket is continuously seeking partners who are willing to develop their business together. If you have any needs related to heavy-duty engine gaskets or require assistance in developing and manufacturing promising heavy-duty engine gaskets.

Some concerns and questions you might have when you would like to make an international purchase, check out our FAQ page for more details or contact MJ sales team now.