If I want to get the part number of a car parts, how I can get it through online ? I do not want to go to a dealer to ask him for the part number. because maybe he will not give me the part number and I do not want to go every time to him.
and how the dealer get the part number ? is it from catalog ? if yes, from where i can get that?
Note: my car is chevy silverado 2011
You can usually go to any of the dealers that have an online parts store, and they have exploded diagrams with the actual OEM part numbers referenced.
Here's a 2001 Subaru Impreza Halfshaft example from parts.subaru.com:
Most dealer catalogs are now electronic, and no, you won't easily be able to get that. Older vehicles (maybe up to the 1995 MY) might be available on microfiche, but this is hard to get as well. Paper parts catalogs went out with carburetors and Hollander Interchange manuals.
Still, those "catalogs" are maintained online for free by dealers, and there's nothing that says you have to order from them. I usually find the part number, and then do a google shopping search for he best price.
@SteveRacer has a great answer, but to be more specific to your particular make of vehicle, try Chevy Online Parts. I'm not endorsing them, but a quick search revealed that you can search for your specific vehicle, and the site provides a list of parts categorized by the component group it belongs to. Then, you get a nice exploded view with labels and part names/numbers.
It's the closest thing I've seen to RealOEM but for Chevy's.
