if it is a 1.4 or 1.6 K series engine its underneath the inlet manifold towards the left hand side ( nearest the belts ) 2.0 T series engine - top left hand front of cylinder head
multiples of 12 are 12,24,36,48,60,72,84,96,108,120,132,144,156,168,and180
Usually located in a removable housing at the engine end of the upper radiator hose
one is located at the thermostat housing. the other is in the bottom of the radiator.
It is located on the top radiator line where it connects to the block. There should be 2 bolts that secure it to the block.
400 ft = 0.07578 miles (1 mile = 5280ft)
Just been looking myself and is 30.
try the left hand side under the bonnet at the front
It si right beside your thermostat housing
1.6 On the rovers the first number is the series model, yours being 4 makes it a 400 series.. the last two are the engine size yours being 16 makes it a 1.6L (commonly termed as a sixteen hundred engine) hope that helps.
It could be a Head Gasket, Thermostat, water pump, bad radiator or just needs coolant. start with the cheapest which is a thermostat.
the lower hose
Left side of the motor right near the distributor and air intake tubing