i have 95 jetta 1.8 litre. The heater does not blow hot air and hasn't for a couple of years. last year i replaced t-stat and that helped a very small amount. 2 months ago the water pump started weaping so i replaced it and the timing belt of course. The hoses going in and out of the heater core are very hot so i know that the hot coolant is running thru the core. I thought that maybe the core was plugged or something so i took the hoses off acouple of months ago and flushed the core. i had very good flow and the water was very clear so i know that the core isnt full of rust or corrosion. i have moved the temp control **** and have heard the blend door moving ( makes that light thump sound when it reaches full swing in either direction. I have considered removing the dash and just doing some exploratory surgery to see what i can find, but i thought i would ask to see if anybody could offer any insight.
Thanks