Volvo 340 1,7 '86

I have trouble with my fuel and temp gauges. They are not working constantly. They behave in the exact same way at the same time. They are apparently connected somewhere. When the fuel stops then the temp stops and vice versa. Most of the time they dont work.

When they work they ...

My 340 1,7l 1986 is leaking coolant pretty heavily. I have located it to come from a drain hole in the bottom of the water pump. I can't hear any special noise from the pump so I think the bearing is OK.

Do you think I have to replace the whole pump with a new one or could it be just a gasket or ...