Volkswagen Repair: heating problem, wv polo, g12 coolant

Question
I have a WV polo 1.4 year 1997

My cabin heater is not working.Everyting seems to be in order. The heating just stooped while i was driving. I checked all parts of heating system.The fan is working,radiator is new,switch is working.I don't think the air is problem.Please help me,thanks.
Best regards,Silvio!  

Answer
Silvio,
  I believe you should try having the system back-flushed.  Sometimes there is sludge buildup, especially if you mix different types of coolant.  Refill with VW G12 coolant only.  See this post:

http://forums.vwvortex.com/zerothread?id=4130196

Rick