Had a 98 E150 with a complaint low air flow through the HVAC. I suspected a plugged heater or evaporator core. To test I hooked up my Smart Smoke to the blower box motor vent and used the water column pressure setting to check the back pressure. 1.5 might not seem like a lot but blower motors are designed to move a lot of air at low pressure so 1.5 inches of water column is a lot. Next I took the cover of the heater core (easy to do), no drop in back pressure. Removed the AC evaporator, plugged with 20 years of debris. Installed a new evaporator core at my suggestion over just cleaning it. Now the back pressure just .4. And air flow is back.
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Last edited by greasybob; 11-05-2017, 08:12 AM. -
Think I would have just hooked up shop air pressure to the evaporator drain and if there was sh@t all over the inside of the cab after letting it rip , I would have known there was stuff in the evaporator.
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I should have added that the measurements were taken with the blower motor on high. The Smart Smoke was used as a low pressure measuring device only.Comment
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Pretty inventive use. Makes ya kinda wonder why the Mid Eastern guy and the Hippie guy sometimes take the machine with them during lunch break.I should have added that the measurements were taken with the blower motor on high. The Smart Smoke was used as a low pressure measuring device only.
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