Keith Browning Posted February 15, 2014 Share Posted February 15, 2014 A 2009 F550 landscraping truck that had little air movement through the HVAC unit and the mode could not be changed. It just kinda gently blew out all of the vents and the floor. No defrost. I have never seen anything like this. First, I decided that with no DTC's there had to be an obstruction or something broken regarding the blend doors. Out comes the dash and some disassembly and I find a bunch of nuts and bolts, a twig, some pebbles and a bit of dirt preventing the floor defrost door from moving. Put it together and checked. The distribution now worked correctly but still very little air movement. UI pulled the blower motor and inspected/tested it and no problem there. We discovered that the cowl was PACKED with organic debris: broken down leaves, pine needles, twigs and dirt all packed on top of the HVAC inlet. Cleaned that out. Still no air. I suspected the "cores" were plugged at this point. By the way that box assembly is a bitch to get out with a 6.4L! Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted February 15, 2014 Share Posted February 15, 2014 Put a little BG Fridgy-Fresh in there, it'll clear that right out. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 15, 2014 Author Share Posted February 15, 2014 I scraped it with a wire brush and attempted to flush it with a garden hose but no luck. That crap is in there to stay. Quote Link to comment Share on other sites More sharing options...
Aaron Posted February 15, 2014 Share Posted February 15, 2014 I remember that stuff brad! Keith, there are products that HVAC guys use on cores like that in outside applications that foam and will take the most plugged looking cores and have them flow air again. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted February 15, 2014 Share Posted February 15, 2014 Meh, I would round file that fucker! Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 15, 2014 Author Share Posted February 15, 2014 He gots a new one. Quote Link to comment Share on other sites More sharing options...
mchan68 Posted February 19, 2014 Share Posted February 19, 2014 Is that the same evaporator used on the 6.7L trucks that like to go South? They use the same style instrument panel, so it only stands to reason that the evaporator has to be identical as well. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted February 21, 2014 Share Posted February 21, 2014 It seems like we spend an inordinate amount of time re-inventing the wheel. In the early 80s, the Escort platform would freeze off the mufflers in the cold (that would be cold on the Canadian scale). Fast forward to 02ish and we see the Fuckus with the muffler freezing off. It's like the lesson was never learned - or perhaps forgotten. Heater cores/evaporators junked off. What else? Young engineers may bring fresh innovations to the product but there is an old adage - if we do not learn from our history, we are doomed to repeat it. Look at it this way.... the guck on the heater core keeps the white flakes from landing on the instrument panel Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted February 21, 2014 Author Share Posted February 21, 2014 This is when you wonder why CABIN FILTERS are not available in Super Duty trucks. If there is a model in Ford's line up that could use one it's that. Can't tell you how many trucks I get in that when I crank the A/C up in the summer and I get a face full of dirt. Oh, and I have to add this: on my final road test with t his truck the blower stopped working... except for high. A new speed control module and it's gone. I am not surprised however as with no airflow to cool it down it probably had been running it little hot. 4 faults with this HVAC box. 4! Quote Link to comment Share on other sites More sharing options...
forddieseldoctor Posted March 2, 2014 Share Posted March 2, 2014 We've had a couple of those. Manegement makes us clean them by soaking them in a sink and then flushing with a hose. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 2, 2014 Author Share Posted March 2, 2014 Another consideration here is what the organic crap is. If there is a lot of pine needles or evergreen of any type it tends to become quite acidic combined with the moisture that condenses on the core. That corrodes aluminum pretty quick. We have seen a lot of that in our Chrysler shop and very little on Fords however. Quote Link to comment Share on other sites More sharing options...
YukonTyler Posted March 7, 2014 Share Posted March 7, 2014 Two of these in the shop on the same day. Both of them are from the same company but came from different job sites. I have one of the two ..... an 08 F350 gas job. It has no real flow from the vents. I pulled the mode actuator and made sure I could manipulate the door by hand - all good. Pulled the blower - nothing there. Dig into the cowling - all sorts of organic debris ..... called an evaporator and got the okay. I'll be doing it next week, and thanks to this thread I breezed through the diag. Thanks guys! Quote Link to comment Share on other sites More sharing options...
YukonTyler Posted March 11, 2014 Share Posted March 11, 2014 2008 left, 2011 right Quote Link to comment Share on other sites More sharing options...
ktmlew Posted March 12, 2014 Share Posted March 12, 2014 This is when you wonder why CABIN FILTERS are not available in Super Duty trucks. If there is a model in Ford's line up that could use one it's that. Can't tell you how many trucks I get in that when I crank the A/C up in the summer and I get a face full of dirt.Oh, and I have to add this: on my final road test with t his truck the blower stopped working... except for high. A new speed control module and it's gone. I am not surprised however as with no airflow to cool it down it probably had been running it little hot. 4 faults with this HVAC box. 4! So anyone have any ideas on how you could retrofit a cabin air filter to these? Quote Link to comment Share on other sites More sharing options...
Aaron Posted March 12, 2014 Share Posted March 12, 2014 There used to be an outfit called cab fresh that made Aftermarket setups. Not sure if they are still around. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 12, 2014 Author Share Posted March 12, 2014 So anyone have any ideas on how you could retrofit a cabin air filter to these? If you remove the plastic cowl trim and look at how that area of the truck is configured you will come to the realization that retrofitting these trucks with a cabin filter is near impossible. The inlet area is encapsulated in sheet metal and the PCM that inserts through the firewall sits directly above the fresh air inlet. Even if you could get a filter mounted in there, servicing it would be difficult at best. This is something that would have to be planned for when the vehihicle is being designed... or redesigned in the furture. Quote Link to comment Share on other sites More sharing options...
8WA Sman Posted May 1, 2014 Share Posted May 1, 2014 I have not seen any evap cores plugged like this but the way I check evap cores for blockage is by watching the high side A/C pressure. With the A/C on and cabin fan on low note the high side pressure then crank the blower to high pressure should raise fairly quickly, then shut the vehicle off turn the key back on with blower on high, pressure should drop quickly. I possible everyone already knows this but just in case someone does not I thought I would throw it out there 1 Quote Link to comment Share on other sites More sharing options...
forddieseldoctor Posted May 1, 2014 Share Posted May 1, 2014 I have not seen any evap cores plugged like this but the way I check evap cores for blockage is by watching the high side A/C pressure. With the A/C on and cabin fan on low note the high side pressure then crank the blower to high pressure should raise fairly quickly, then shut the vehicle off turn the key back on with blower on high, pressure should drop quickly.I possible everyone already knows this but just in case someone does not I thought I would throw it out there Hmm I learned something new today. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted May 1, 2014 Share Posted May 1, 2014 I don't see how that's going to work for air flow restriction... Is my feeble old mind missing something? Quote Link to comment Share on other sites More sharing options...
Aaron Posted May 3, 2014 Share Posted May 3, 2014 If it's not blowing air across the core, the refrigerant can't remove heat and the AC system won't work as hard to cool what it thinks is already cool due to lack of hot air flow. Quote Link to comment Share on other sites More sharing options...
8WA Sman Posted June 6, 2014 Share Posted June 6, 2014 Here is one of the cabin filters that I replaced on GM truck today. Just by replacing the filters I dropped the vent temp over 15 degrees and eliminated the rapid a/c compressor cycling. I would think that the above plugged evap core might have had similar symptoms but each HVAC design has different characteristics and have not ran into an '09 SD to know for sure. Quote Link to comment Share on other sites More sharing options...
Buddy_M Posted October 21, 2014 Share Posted October 21, 2014 Did diag on one about 2 weeks ago with no airflow and just came in to start on it late yesterday, got box out this morning and taking break now before it goes back together.. yea I now understand why these are hell to pull in a 6.4, I popped out the dipstick and made it quite a bit easier to get the two nuts behind the engine. This truck has just over 50k miles, but engine hours are nearing the 11k mark. It sits on location just idling for weeks at a time during frac as this is the on site crew truck, they have 2 other trucks that come out to rotate crews. Quote Link to comment Share on other sites More sharing options...
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