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Topic: Mk2 Jetta cooling diagrams  (Read 418 times) previous topic - next topic

Mk2 Jetta cooling diagrams

Hi, I have a 1990 VW Jetta 1.8petrol.  When I bought it it wasn't blowing any hot air through the vents into the cabin. I have changed the heater matrix, the thermostat and still there is still only cold air coming through the vents. Would anyone have any cooling diagrams to help me get a better understanding of what I will have to do next?
Thank you.

Re: Mk2 Jetta cooling diagrams

Reply #1 –
It will most likely be the foam covering that has perished and disappeared from ion the flaps within the heater box. It’s the flaps that direct the hot and cold so without you can’t shut off the outside cold airflow.

The only other thing it could be is if the matrix bypass valve is still in situ, it could be bunged up with gunge and reducing water flow to the matrix.

Heater box foam replacement and the bypass issue is documented on this site if you browse around the technical areas.