The service jack that is provided with your vehicle is designed for changing tires. It should NOT, under any circumstances be used to support the car while you crawl under it and work. To do so is to recklessly jeopardize your life. Whenever it is necessary to get under a car to perform service operations, always be sure that it is adequately supported using jackstands at the proper points. Also, be sure to always block the wheels when changing tires.
Once the jackstands are in position and the vehicle's weight has been lowered onto them, shake the car a few times before crawling underneath to make sure the jackstands are securely supporting the weight.
Service operations in this information often require that one end or both ends of the car be raised and safely supported. The ideal method, of course, would be to use a grease pit or a hydraulic hoist. Since this is beyond both the resources and requirements of the do-it-yourselfer, consider more practical equipment. A small hydraulic, screw or scissors jack; or else a floor jack will raise the vehicle sufficiently for almost all the procedures in this guide. The rolling floor jack is probably the easiest and most convenient of these to use. But the vehicle must still be supported by at least two sturdy jackstands, if you intend to work under the car at any time. When using a floor jack, raise the front of the vehicle by positioning the floor jack under either the subframe or body side rail behind the engine support bracket. The rear may be lifted by positioning a floor jack under either rear suspension body bracket. Under no circumstances should the vehicle ever be lifted by the front or rear control arms, halfshafts or CV joints. Severe damage to the vehicle could result. An alternate method of raising the car would be drive-on ramps. Be sure to block the wheels when using ramps. Spend a little extra time to ensure that your car is lifted and supported safely.