I'm experiencing a similar problem with my '87-S10 w/o AC. I've traced it down to a broken link on the damper/valve inside the distribution box set just in front of the front floor console, mounted up against the firewall, and 3/4 under the dashboard.
When I change the control panel settings between FLOOR, VENT & WINDSHIELD, I can hear the damper moving, then all of a suddden there's a clunk and nothing realy changes. I am getting a moderate flow of warm air at all locations, but I'm not getting anywhere near the volume I used to get.
I've replaced the heater core - It was OK, but got damaged in the removal process. I had to flatten the piping in order to remove the hoses, which was too bad because the replacement core is not near as good as the original equipment. All it realy required was a good dusting.
Once I removed the shroud covering the heater core under the dashboard, I was able to see into the central distribution box. What appears to have happened is that the hinge pin which ties the actuating arm to the damper (connected I think, to the vacuum control valve located on the left (driver's) side of the distribution box) has broken off. As the arm passes by the damper's lever arm, it snags on the hinge pin and attempts to lift it, then slips off resulting in the clunk sound that I was hearing.
Any help would be appreciated.
11-13-2004, 10:43 AM
