A tensioner comprising a piston slidably received within a piston bore of the housing having a plurality of grooves formed on an outer circumference, the piston forming a first pressure chamber with the piston bore. The tensioner uses a mechanism to remove a sliding pawl or expandable clip from engaging the grooves on the piston, such that the piston can move towards the housing and reduce chain load when fluid pressure is reduced in the first pressure chamber during engine shutdown, but not so much as to leave the chain uncontrolled during engine restart. The mechanism may for example be a fluid biased spool piston which engages the expandable clip or a pawl piston that engages a sliding pawl.

A number of variations may include a product including a tensioner for a vehicle engine chain comprising a piston housing body portion having a piston bore formed therein for slideably receiving a piston connected to a chain guide shoe, and a camshaft bearing support or a combustion engine cylinder block or an engine cylinder head, extending from the body portion.

A linear tensioner is provided for tensioning a traction mechanism provided in a drive system with a first adjustment element that has a hollow-cylindrical construction and a second adjustment element that is guided so that it can be moved longitudinally on this first element, wherein contact surfaces are formed on facing end surfaces of the adjustment elements, on which a compression spring actuating at least one of the adjustment elements in the tensioning direction is supported. A transport securing device is provided that prevents, in a specified locked position, a movement of the adjustment elements relative to each other by at least one locking element. For creating a linear tensioner, in which, due to the use of a transport securing device, the structural dimensions of the linear tensioner are not increased, the adjustment element is movable out of the locked position against the force of the compression spring into an unlocked position, in which the at least one locking element is automatically displaced into a receptacle of the one adjustment element, whereby the adjustment elements are permanently unlocked relative to each other.