The orifice in the heater control valve is pretty small and easily
blocked. In the early water-cooled models the long coolant pipes are
metal and prone to corrode inside. The corrosion builds up into large
chunks and these chunks can break loose and start to move around the
cooling system.

If you verify that the the heater valve is being properly actuated by
the cable, try replacing the valve as they are less than $15. If that
does not help, flush the front heater system. I do this by cutting the 2
heater hoses as far to the rear as I can easily access them both. Open
the heater valve and run a garden hose into each end in turn to flush
the lines and heater core. The crap that comes out may surprise you.
Then use 2 house couplers and 4 hose clamps to reattach the hoses. If
you cut them an inch or so apart you can tell which end goes where. Use
one of the couplers to plug the other 2 ends together while you do the
flushing. This will greatly reduce the amount of coolant lost.

Mark

Dave Vieira wrote:
>
> hey !
>
> well its damm cold out(- 9 C)now and still no heat, im
> still
> tryin to figure out if its air or not that is causing
> it. but i donno .. i replaced the line that runs from
> the expansion tank to the res tank .. and now what
> happens is.. it dosnt over heat .. the temp noramal
> drving is little over the middle of the bulb to the
> end of the bulb .. when climbin up hill it gos little
> farther away from the bulb but not too bad it cools
> down when i get to top .. highway driving same .. the
> needle is at the end of the bulb .. but still blowing
> cold air.. after i get out of the van i do notice a
> smell of rad fluid and the res tank is little over the
> max but. .when i come back to it .. when it is cold ..
> the res tank is down in the middle of max and min. ...
> i still get no heat at all i do the oddest times . but
> it dosnt last long ..  i drove it from hamilton to TO
> on firday .a nd when i got to about the gardner i got
> heat for about 5 mins.. then cold .a nd on the way
> back got nothing.    what do you make of this ?
>
> thanks for you help
>
> 84, 1.9 Vanagon
>
> =====
> Dave Vieira
> Hamilton, Ontario
> Canada
>
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