What is the Difference Between a Diesel’s Engine Wet and Dry Sleeve?

All internal combustion engine use sleeves or as some  can call it, liner. In terms of cooling system, engines can be classified as water cooled and air cooled engine.

The air cooled engine use a different type of sleeve with fins. But the liners of water cooled engine can be divided into two, the dry sleeve and the wet sleeve.
Let’s talk about the dry sleeve. A dry sleeve simply means there is no contact between the sleeve and the coolant. It means the coolant is not directly touching the sleeve. Rather the sleeve has another metal wall which is refered to as engine block. The dry sleeve is installed in this metal wall of the engine block.
This means that the coolant is in direct contact with the metal wall of the engine block not the sleeve. If for any reason the coolant is in contact with the sleeve, it means there is a crack on the metal wall which the sleeve was installed.

Let’s talk about the wet sleeve. The wet sleeve is the opposite of the dry sleeve. The coolant is in direct contact with the sleeve. There is no metal wall between the sleeve and the coolant is cooling the sleeve via direct contact.

What are some differences between the two:
1. The wet sleeve usually has sleeve rubbers or liner seals but dry sleeve do not have the seals. Because the coolant is touching the wet sleeve, seals are needed to prevent the coolant from going down to the sump. 
2. Another difference is that the wet sleeve is usually thicker than the dry sleeve: Because of direct contact with coolant there is need for the wet sleeve to be thick so that corrosion will not quickly damage it. Since there is no metal wall that protects it, the wet sleeve needs to be thick.
These are the major differences between the wet sleeves and dry sleeves.