Vectra c no heating

[David2572]

Can anyone help, my car has no heat just blows cold air, temp staying at 100 degrees Celsius

Coolant temp rising in expansion tank when it gets to operating temp. Garage said its a blown head compression to coolant I have done a block test which was negative and a compression test which was 127psi across all 4 cylinders. Only 1 pipe is hot on the heater core it isn't blocked though as water is flowing through. New water pump and thermostat fitted. Any ideas what else could cause this

[soulman]

It may be that your thermostat is fropard , cheap and easy to swop,
ar just read you have changed the thermostat/ was it a cheap ebay one or genuine stat ??

[troutybrown]

Air lock and also expansion tank caps failing is a common problem. These engines run at 105 degrees the cap allows the pressure which raises boiling point of coolant. When valve in cap fails it starts to boil at 100.

[Jon1796]

If the rest is ok could be mixer flap control motor is broken or dead. As no movement to to allow hot water through.