Passat b5 poor heating in cabin

Passat b5 poor heating
So the passat has low heating the motor flap for hot hoses all the temperatures on the 90c hose from the heating of the small cooler the hot wind it is possible to be caught and a bit slack only?

is possible that the fridge clogged cabin to check it?

heater core is probably clogged. Common issue

I have had good success flushing them out with a garden hose and some CLR or vinegar.

Had mine back flushed year ago.
Still working fine