Different kinds of gaskets, #4 indicating a V4 head gasket.

A replacement head gasket sitting loosely on top of a four cylinder engine block. One positioned correctly the cylinder head will be bolted down on top of it.

A head gasket is a gasket between the engine block and cylinder head in an internal combustion engine. Its purpose is to seal the cylinders to ensure maximum compression and avoid leakage of coolant or engine oil into the cylinders; as such, it is the most critical sealing application in any engine, and as part of the combustion chamber, it shares the same strength requirements as other combustion chamber components.^[1] Image File history File links Download high-resolution version (510x700, 72 KB)Gaskets: o ring fiber washer paper gaskets cylinder head gasket Scan, upload MH 11:06, 2005 Jun 19 (UTC) I, the creator of this work, hereby release it into the public domain. ... Image File history File links Download high-resolution version (510x700, 72 KB)Gaskets: o ring fiber washer paper gaskets cylinder head gasket Scan, upload MH 11:06, 2005 Jun 19 (UTC) I, the creator of this work, hereby release it into the public domain. ... 1700 cc High Compression Ford Taurus V4 A V4 is an engine in V configuration, with 4 cylinders. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2560 × 1920 pixel, file size: 683 KB, MIME type: image/jpeg) Please see the file description page for further information. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2560 × 1920 pixel, file size: 683 KB, MIME type: image/jpeg) Please see the file description page for further information. ... Some seals and gaskets 1. ... An engine block is the main part of an internal combustion engine. ... The cylinder head from a GMC van. ... This article does not cite any references or sources. ... A combustion chamber is part of an engine in which fuel is burned. ...

Types of Head Gasket

• MLS - stands for "Multiple Layers Steel,". Most modern head engines are produced with MLS gaskets. These typically consist of three layers of steel.

The contact faces are usually coated with a rubber-like coating such as Viton that adheres to the cylinder block and cylinder head respectively whilst the thicker center layer is bare. Viton® is a synthetic rubber and fluoropolymer elastomer commanly used in o-rings. ... The cylinder block of a Ford I4 DOHC engine The cylinder block or engine block is a machined casting (or sometimes an assembly of modules) containing cylindrically bored holes for the pistons of a multi-cylinder reciprocating internal combustion engine, or for a similarly constructed device such as a pump. ... The cylinder head from a GMC van. ...

• Solid Copper - A solid sheet of copper, and typically requires special machining called 'o-ringing' that places a piece of wire around the circumference of the cylinder to bite into the copper. When this is performed copper gaskets are extremely durable. Recently companies have started producing copper gaskets with integral sealing wires permitting their retrofit into engines without the removal of the engine block for machine work.

• Composite -- an older technology. Typically these are made from asbestos or graphite but are more prone to blowouts than newer gaskets. Asbestos gaskets are becoming increasingly rare due to health concerns.^[2]

Cylinder with piston in a steam engine A cylinder in the central working part of a reciprocating engine, the space in which a piston travels. ... An engine block is the main part of an internal combustion engine. ... Fibrous asbestos on muscovite Asbestos Asbestos Blue asbestos (crocidolite) from Wittenoom, Western Australia. ... Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): to draw/write, for its use in pencils) is one of the allotropes of carbon. ...

Gasket problems

Occasionally, the compression in the cylinder may cause a leak to form in the gasket (a "blown" head gasket). This problem has been exacerbated by the use of aluminum rather than iron cylinder heads; while lighter than iron, aluminum has a much greater thermal expansion rate, which in turn causes a great deal more stress to be placed on the head gasket. Engine makers have responded to this by adding a non-stick coating such as Teflon to the surface of the head gasket. Bold text The compression ratio is a single number that can be used to predict the performance of any engine (such as an internal-combustion engine or a Stirling Engine). ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... In physics, thermal expansion is the tendency of matter to increase in volume or pressure when heated. ... Teflon is polytetrafluoroethylene (PTFE), a polymer of fluorinated ethylene. ...

A damaged head gasket can cause compression to leak between cylinders.

If the gasket blows, a variety of problems can occur, from compression loss (leading to power reduction, or a rough engine), to exhaust gases being forced into the cooling system, leading to the engine overheating and increased engine wear due to the motor oil being mixed with antifreeze. Coolant can leak into the cylinders, causing the exhaust to issue steam;^[3] if a very large amount of coolant does this, hydrolock can occur, causing extensive engine damage. Sometimes, all that may happen when a head gasket is blown, is excessive steam erupting from the tailpipe and the engine may act and drive like normal. Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2560 × 1920 pixel, file size: 876 KB, MIME type: image/jpeg) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2560 × 1920 pixel, file size: 876 KB, MIME type: image/jpeg) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A typical container of motor oil, with some in a glass. ... Antifreeze is a water-based liquid coolant used in gasoline and diesel engines. ... In automotive terminology, a hydrolock is the immobilization of an engines pistons by a liquid (usually water, hence the prefix hydro-). Hydrolocking occurs when liquid fills a cylinder on the intake stroke and, due to the incompressibility of a liquid, makes the compression stroke impossible. ...

Head gasket condition can be investigated by checking the compression pressure with a pressure gauge, and the pressure in the cooling system. Oil mixed with coolant and excessive coolant loss with no apparent cause can also be signs of head gasket problems. Driving with a blown head gasket (if possible) can cause additional extensive damage due to overheating or loss of lubrication. Many techniques have been developed for the measurement of reduced or increased pressures. ...

References

External links

• Ask's Head Gaskets and Valve Covers Q&A