oil pressure gauge

  1. M

    Does anyone know what the hole to the left of the oil pressure sender is for??

    I was replacing the oil pressure sender on my 1989 mustang 5.0 when I accidently knocked a plate off this hole. It was very badly attached by a previous owner and I have no idea what belongs here. I found pictures of what goes here but I have no clue what it is or does. I’ve been running my...