I need to change my oil filter and need to know what size to buy for the oil filter cap/wrench.

If you can't remove the filter by hand just use a common oil filter wrench. The filter is easy to access and remove. When you buy your new filter you can find the correct size filter cap wrench which is most likely a 64 mm.

You only need a few. You need a wrench or socket that fits the oil pan drain plug. Car makers have used all sizes of drain plugs, don't know Saturn's, anywhere from 13 millimeter to 19 millimeter size wrench or socket. One of them will fit yours.
So one wrench (when you find the right one) and you will need a drain pan to catch the oil. Next you will need an oil filter wrench or tool. There are several types and sizes-when you buy the new oil filter you can get the filter remover that fits your filter . A parts person should be able to help you select the right one. Also buy a small funnel to pour new oil into the engine .And don't forget to have a few rags handy to clean up spills and wipe off areas. That's about all that is normally required.

most cap -- ie filter wrenches, use a 3/8 drive

1. Ramps or jackstands (do not do this with only a jack)
2. Appropriate wrench to fit the drain plug
3. Filter wrench for your filter size (when you buy the filter you can decide which size you need - there are 2 sizes)
4. Drain Pan
5. Oil filter and Appropriate amount of oil (recc - 10W30)
6. Creeper for comfort if you prefer
7. A bundle of rags

It is an internal filter. It is located in the oil pan. It has a cap on the oil pan that almost looks like you can take it off with your hand. Chances are however you cant. You can change it yourself with the correct size oil filter wrench. I wish I could tell you what size it was but I use a strap wrench to take it off. Most places sell the filter. Fram # is Ch8765.

for the time being a 12 inch cresent wrench will do but be carefull ;once you break it louse use your fingers to do the rest.remove the filter and replace with new 1.snug it tight then 1/4 turn if that,refill through the valve cover.hope this helps

I'm not sure why everybody is going to the oil filter canister system. Doesn't make my job at work easier.
You'll need this tool here: TOY640
http://www.toolrage.com/prodview.asp?sku=ASM-TOY640
Any other tool will crack the cap and make life go bad after that.

Good luck, Mike.

the engine takes 4qts w/filter and the drain plug is 17mm.

Under engine, look for a round big plug plastic with star head. Need special oil filter wrench, can buy it at any auto parts.

If you have never changed your oil before use care:

0.) Safely Jack up vechile
1.) remove oil filler cap
2.) remove oil drain plug on oil pan
3.) Let oil drain into a container
4.) Flush a quart of through with the drain plug removed to get any deposits out.
5.) remove and drain oil filter
6.) install new oil filter(make sure you put some oil on the filters gasket by hand)
7.)Install oil drain plug
8.) Re-fill with oil
9.) Put oil filler cap back on

Hope this helps and again use with care if you have never turned a wrench before, people get hurt easily by being careless while working under a car.