Heater doesn't work so good - 74 Duster
Sounds a lot like the air door not coming open or inlet opening is blocked. Getting into these things under dash is a good line of work for a contortionist. Hose hook up matters because thermal convection helps pull flow through the core evenly. Hot water goes to the lower half of horizontal tubes, rises up on the small tank end and comes back across the upper set of tubes. It doesn't work too well trying to push hot water downward through the restriction of the core tubes, steam bubbles tend to restrict water flow.
Sounds a lot like the air door not coming open or inlet opening is blocked. Getting into these things under dash is a good line of work for a contortionist. Hose hook up matters because thermal convection helps pull flow through the core evenly. Hot water goes to the lower half of horizontal tubes, rises up on the small tank end and comes back across the upper set of tubes. It doesn't work too well trying to push hot water downward through the restriction of the core tubes, steam bubbles tend to restrict water flow.
