I've always installed a T fitting behind the oil pressure switch to run a oil pressure gauge...Prince Valiant said:Most engines I've worked with, it's not unusual to have multiple drains for the coolant.
Another possibility is it could be an oil galley plug. Most are contained within the engine, but some engines will have a threaded external galley plugs...Could be a spot to have a mechanical oil pressure guage threaded in as well.
No, I don't have one in my Insight, I had one in my old Civic.pretendtobenormal said:So you have an oil pressure gauge in your Insight? What size and how do you have it mounted?