Head Gaskets Diesel - Cummins, Duramax, Powerstroke

Head gaskets are the most important sealing application in the engine. Being part of the combustion chamber, it must be as strong as the other pieces of a vehicle’s combustion chamber. They sit between the engine block and cylinder head. The part’s purpose is to keep the cylinder’s sealed, ensuring the maximum level of compression while assisting in preventing coolant or oil from leaking into the cylinders. It also seals water and oil passageways between the head and the block. Many modern engines are fabricated with MLS (Multiple Layers Steel) gaskets. These consist of three steel layers with contact faces that are usually coated with a rubber-like adhesive which grabs onto the cylinder block and head, leaving the thicker center layer bare. Solid copper sheets are another way of manufacturing these gaskets, but they usually require special machining called 'o-ringing'. This process surrounds the cylinder with a piece of wire to bite into the copper. These copper gaskets are some of the most durable, and many companies have even started producing them with all of the sealing wires needed to allow the newer gaskets to be adapted to the engines without necessitating removal of the engine block for machine work.

What Can Happen When a Head Gasket Blows

Blown gaskets can cause serious engine damage, and if left untreated, can require more expensive work than to repair the initial problem. Aluminum is lighter than iron, but expands much more rapidly with heat. This causes more and more stress to be put on the head gasket. Gasket failure causes a variety of problems to occur, from compression loss to exhaust gases being forced into the cooling system, which causes the engine to overheat and increases engine wear as the oil mixes with the antifreeze. Sometimes, the cylinder’s compression can even cause a leak to form in the gasket. If this occurs, then the gasket will need to be replaced. This is usually called a blown head gasket, but the problem usually has more to do with the aluminum based composition of the cylinder heads. Blue or white exhaust smoke can be indicative of oil or coolant burning, respectively. Air pockets can form, causing the engine to shoot out coolant into the overflow tank, which reduces how much is available in order for the engine to maintain its cool temperature. Leaking head gaskets can be classified as external or internal. Oil which contains a substance looking like mayonnaise, seen on the dipstick or cap is another good sign of head gasket failure. This is not definite evidence of gasket failure, since the oil can mix with coolant through other routes.