Engine mounts do not need much maintenance, although damaged or worn mounts are to be changed as soon as possible because they add an additional load to some of the components of the drive line and can lead to damage or wear. In order to test the mounts, lift the engine a little to take off the weight of the mounts. Start with a car and place it on jackstands while keeping it high to avoid its damage, and place the jack below the engine oil pan with a big woodblock. When the engine is only held by a jack carefully raise it until the weight is removed off the mounts, and no portion of your body is under the weight of the engine. Checks of the mounts to be made on cracks, hardened rubber, or separation between the mount and the bushing in the center. Test the relative motion between the mount and engine or chassis with a large screwdriver or prybar, and in case movement is detected, lower the engine and adjust engine mount fasteners. To change the battery, first, you have to take off the battery cover and disconnect the negative battery terminal and then you have to raise the vehicle and then hold on to it using the jackstands unless you have already done that. Make sure that a floor jack is placed under the engine, with a wood block, and then make the jack a bit higher to take pressure off the mounts. Unscrew the screws and take the mount off the frame/body and engine making sure not to unscrew more than one mount at a time unless during an engine removal. The opposite of removing is installation, which involves adding thread-locking compound to the mount bolts and tightening them up.