The hood on your vehicle is held open in one of two ways. It is either supported by a long metal rod that you swing up from the inside of the engine compartment and insert into a hole in the hood, or by a pair of hydraulic struts that resemble mini shock absorbers.
A hood support strut is a metal cylinder with a metal rod that telescopes from one end. The cylinder is also filled with hydraulic oil or inert gas that constantly pushes to expel the rod, effectively extending the strut to its full length, kind of like a pogo stick. One end of the strut is attached to the hood, and the other is attached to a structural part of the vehicle body. Also found at each end of the strut is a ball and socket or a hinge that can move with the hood.
When the hood is opened all the way, the pair of struts work to keep it open. But when the hood closes to a certain degree, somewhere around halfway, the weight of the hood overpowers the struts, and the hood closes
Hood support struts are usually replaced in pairs, except in the less-common case that the hood only features a single strut. Some support struts are held in place with a screw-in stud at one end and a hinge bracket at the other. Some have a retaining spring-clip that holds the ball and socket together. The methods required to detach them are slightly different.
To replace the support struts, a technician will take the following general steps