The Volkswagen air-cooled engine is an air-cooled

Air-cooled engine

Air-cooled engines rely on the circulation of air directly over hot parts of the engine to cool them.-Introduction:Most modern internal combustion engines are cooled by a closed circuit carrying liquid coolant through channels in the engine block and cylinder head, where the coolant absorbs heat,...

 boxer engine with four horizontally opposed cast iron

Cast iron

Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...

 cylinder

Cylinder (engine)

A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

s, cast

Casting

In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process...

 aluminium alloy

Aluminium alloy

Aluminium alloys are alloys in which aluminium is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories...

 cylinder head

Cylinder head

In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...

s and piston

Piston

A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...

s, magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

 crankcase

Crankcase

In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...

, and forged steel crankshaft

Crankshaft

The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

 and connecting rod

Connecting rod

In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion....

s.

Variations of the engine were produced by Volkswagen plants worldwide from 1936 until 2006 for use in Volkswagen's own vehicles, notably the Type 1 (Beetle), Type 2 (bus, transporter)

Volkswagen Type 2

The Volkswagen Type 2, officially known as the Transporter or Kombi informally as Bus or Camper , was a panel van introduced in 1950 by German automaker Volkswagen as its second car model – following and initially deriving from Volkswagen's first model, the Type 1 , it was given the factory...

, Type 3

Volkswagen Type 3

The Volkswagen Type 3 was a range of small cars from German manufacturer Volkswagen , introduced at the 1961 Frankfurt Motor Show, Internationale Automobil-Ausstellung ....

, and Type 4

Volkswagen Type 4

The Volkswagen Type 4 is a mid-sized car manufactured and marketed by Volkswagen of Germany from 1968-1974 in two-door and four-door sedan as well as two-door station wagon body styles...

. Additionally, the engines were widely used in industrial, light aircraft and kit car applications.
Like the Volkswagen Beetle

Volkswagen Beetle

The Volkswagen Type 1, widely known as the Volkswagen Beetle or Volkswagen Bug, is an economy car produced by the German auto maker Volkswagen from 1938 until 2003...

, the first Volkswagen Transporter

Volkswagen Transporter

The Volkswagen Transporter, based on the Volkswagen Group's T platform, now in its fifth generation, refers to a series of vans produced over 60 years and marketed worldwide....

s (bus) used the Volkswagen air-cooled engine, a 1.1 litre

Litre

pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...

, DIN

Deutsches Institut für Normung

is the German national organization for standardization and is that country's ISO member body. DIN is a Registered German Association headquartered in Berlin...

-rated 24 kW (24 PS, 24 bhp), air-cooled four-cylinder "boxer" engine

Flat engine

A flat engine is an internal combustion engine with multiple pistons that move in a horizontal plane. Typically, the layout has cylinders arranged in two banks on either side of a single crankshaft and is sometimes known as the boxer, or horizontally opposed engine. The concept was patented in 1896...

 mounted in the rear

Rear-engine design

In automobile design, a rear-engine design layout places the engine at the rear of the vehicle. The center of gravity of the engine itself is past the rear axle...

.