[Jims5543]

My RX7 has a low oil level sensor that will alert me if I am a quart low. It will go off when I am Autocrossing and getting all the oil to one side of the pan its a light and a very loud buzzer.

It also has a coolant level sensor that triggers a light and the same loud buzzer if my coolant is more than 1/2" from the top of the radiator.

This car was built in 1987.

My sons E30 has the same deal for the oil, it will tell you if your a quart low. I am not sure about the coolant and suspect it does not because right after he bought it and we got it home we pulled the radiator and in only had a liter of water in it.

As far as a gauge goes I think that would be overkill and sensor that indicates your at your low limit seems to work just fine.