My 2002 Protege ES is due for an oil change. Can anyone tell
me where the oil filter is located? What is the size for the
drain plug. Thanks for your help.

 

My P5 drain plug is 19 mm. The filter is on the back of the engine underneath the intake manifold. In order to reach it, lay down under the car with your shoes sticking out the front. Scoot back until your chin is just past the oil drain, and look up. There's a cavity there and the oil filter is in there... feel around a bit, and you'll find it. Oh... and the OEM filter is black, so you can't miss it in the dark ;-)