Whether you have a sedan or a truck, your car has a set oil intake. If you plan to do your own oil change, you first need to determine your car's engine oil capacity. You don't want to overfill it because the oil may find its way into parts of the engine where you don't want it to go. You also don't want to under fill it either, since you may find the engine under lubricated and subject to overheating.
How to Find Out How Much Oil Your Engine Takes
Your Owner's Manual
Most owner's manuals list the engine oil capacity under 'Lubrication System' in the 'Vehicle Specifications' section.
The Manufacturer's Website
Once on the website, look for a section of the site specifically for vehicle owners, usually found at the bottom of the page.
Other Online Resources
If you're still having trouble locating the information, do quick search online. There are several websites that list the oil and fluid capacities of a number of different makes and models of cars and trucks.