I have a 2006 Chevy Malibu 2.2 Ecotech. I can't loosen that pulley unless I take off that motor mount that's in the way.I don't have a jack so. Can I successfully remove the motor mount then put on the belt on my new alternator. Or is the engine gunna fall without the mount?? I know probably a dumb question...
Option 1: use your spare tire jack with a 2x6 and jack engine at oil pan. Do not lift too hard or you'll damage pan.
Option 2: remove hood and use a come a long and lift from the top.
Best option: you are doing your own work so it is important to have the right tools to do it. This is for efficiency and safety. If you buy an adequate jack you will still save money and will be able to utilize it for future endeavors.
If you only have a bumper jack, try it this way. Raise the fromt bumper about 6 inches at the proper side. Loosen the motor mount bolts a bit. Place sturdy wood blocks under the engine close to the motor mount side. Start to lower the bumper jack and you will see the engine rise. Remove the bolts and continue to lower the front bumper. Stop lowering as soon as you can wiggle the mount away and out. Reverse to install the new one.
One way to support the engine without a jack to remove the motor mount is by using an engine support bar. I've used one for a timing belt change when the motor mount had to be removed. The photo below shows how it works. You could make something like this out of lumber, a threaded rod and some chain, or you could possibly rent one. Photo credit: ECStuning.com
Alternatively do it a different way
I found it hard to believe that replacing a serpentine belt would need anything as drastic as removing engine mounts. True enough when I did a quick google (for "chevy malibu 2.2 ecotech serpentine belt"), the answer is simply that you're not doing it right.
From this link and various others, it seems that a special tool exists which is basically a very long, thin wrench. You can buy this tool, or fabricate your own. Granted that this is going to be an expensive tool, it's still going to be way cheaper than buying an engine hoist, or a long-reach jack and stands. And it's going to be waaaay cheaper than the time you'll spend lifting the engine, not to mention the distinct possibility that you'll bust the pan and have the extra cost and time of replacing that too.
That search also put up a bunch of Youtube videos. I've not checked them myself, but it seems likely you can learn from other people's experience on doing the same job.
Just as a general point by the way, please do google your problem before posting. The link above was just the first page from that search, so you could have found it yourself for less time than it took you to post here.