These are actually classic torsion springs. They work in the same way as the ones which have not received any treatment. They are mounted over the shaft and apply torque to the drums and cables to enable the lifting of the overhead door. The unique thing about them is their make. They are made from steel wire which has been dipped in hot oil. The presence of the oil eliminates the need for lubrication maintenance. At the same time, the component gets a lower rate of wearing. These special springs are recommended for heavy doors and for ones which are used many times during the day. Their only drawback is that they leave residue on the door while working. As a result, the panels require cleaning more often.
The role of garage door springs is to counterbalance the door. For this, they get loaded with energy whose amount corresponds to the weight of the door. When this energy is higher or lower than the optimal, problems with closing and opening occur. The good news is that the tension can be checked regularly with a simple test. It starts with disconnecting the opener and lifting the door manually. When the door is halfway open, it is released. If it shoots up, the tension has to be reduced. If it drops down, the tension should be increased. The adjustment involves unwinding or winding the spring respectively. Usually, there is no need for further repair. The test is repeated to ensure that the door works as it should.