Can anyone tell me what the oil filter adapter is for? Based on our book we have this installed on our 96, but it appears to have a leak... What the heck is it? What is it doing for me?

the oil filter adapter allows you to put an oil filter on, it probably also connects to the oil lines going to the radiator for cooling. The gaskets for it don't cost much, but can be a little bit of a pain to change them.