I'm thinking this part is a sensor for oil pressure. it is located on the back of the block and actually screws down into the block behind the intake manifold. when i took my block apart to get it rebuilt, i unscrewed it out of the block and found that the plastic is actually breaking apart from the metal elbow. i need to know for sure if thats what that part is so that i can order a new one. thanks.
dave

 

It sounds like the oil pressure sending unit.

 

Yup thats what it is...i forgot to take mine off and the machine shop lost it, errrr 25 bucks for a new one from napa...it never ends.