as title, put this up for a mate, basically the heater is set to hot but blowing cold? what is up with it, thermostat?

 

First thing id be checking is the water level

 

More than likely to be the thermostat

 

If this issue is merely a coincidence with the cold weather then so be it, check the thermostat in a pan of boiling water (or alternatively, for the cost just fit a new one), but i suspect not.

As said, check coolant level, and anti freeze content. Bleed system if applicable.

It might be the case the pipes to the matrix have frozen...?

Tom

 

What is the gauge on the dash doing?

 

Could the water pump be faulty. not sure on the tdi but my octavia water pump broke into 4 bits due to it being made of plastic

 

Thats right, some VW pumps have plastic blades, and shear with or without ice.

Tom