1997 Ford Mondeo Has my head gasget gone?

Engine Cooling problem
1997 Ford Mondeo Front Wheel Drive Manual 176000 miles

I have an Rreg Mondeo and I have recently noticed that my coolent level keeps dissappearing I can see some water leaking from the lower Left near the sump sort of area. My car heats up quite quick but the other day I filled the expansion tank with anti-freeze and drove for 15miles and when I got home it was all gone. I think that the water dissapears when I go round a sharp corner but it does not seem to circulate but pipes rad pipes are hot and heater works so it must be but I see no return to expansion tank. I sat out side hoem earlier with the expansion tank full to max let the car heat up reving around 2000 revs till the fan kicked in but no water curculated but again hot rad pipes. I think that possibly the water pump or leaking head? As no obvious signs of head gasget gone ( no white stuff in oil starts and runs fine) there also seems to be pressure in expamsion tank as normal. Also temp gauge works ok then when I go round a corner it stops working. Please help just hope it not head gasget.