My 1998 vauxhall corsa only blows cold air even when the heating is on?

You need to replace the Thermostat.Follow the Upper Radiator Hose,it should go into a Metal Housing on the outside of the Engine Block.Should be Two Bolts holding that Housing to the Engine Block(Thermostat Housing).Undo the Jubilee clip on the upper Radiator Hose and remove the hose from the Car.Unbolt the Thermostat Housing from the Engine.You may have to undo other Waterhoses before you remove the Housing,all
cars differ.You will find the Thermostat inside the Housing,be careful you install the new one the same way/do not remove the Thermostat until you are sure which way it is fitted.install new Thermostat, clean the Housing Surface where it bolts to the Engine/be sure to clean the Engine block side too. Apply Red or Blue Gasket Maker to the Thermostat Housing End, then fit it back to the Engine and rebolt it to the Engine Block..reinstall hose You are done and just saved yourself 50/ 75 quid labour! Should take less then an Hour.Your old thermostat is no longer opening,thus no heat!
You need to buy..
1. Thermostat
2.Waterpump/Thermostat Gasket Maker
Should be about 15 quid all in!
You could buy a new Thermostat Gasket, it is cheaper to use Gasket maker.Good Luck!

englander1971
March 2008