Hi guys i have a mk1 focus zetec climate 2.0 that had water pump explode/replace before i bought it. The prob i have is the temp guage reaches normal fairly quick within 1.5 miles the heaters feel warm but when you put blowers on they go cold. Also when you pull up and turn off engine you can hear and aee the water bubbling in the expansion tank. Start engine count to 5 and it all stops. No sign of water loss. Could this be poss headgasket?