Littlebeefy Posted July 23, 2020 Share Posted July 23, 2020 Hi folks, My original A/C on my 351W worked for about 60 days after I got it "fixed" a few years ago, and has not worked since. Just blows warm air. I finally had a mechanic who knows these trucks look at it and he said, "this is the original system; don't try to fix it, just replace the compressor and hoses." I replaced a broken heater blend door behind the dash earlier this year, and now everything HVAC related in the interior seems to be operating (except for the lack of frigidity). So my question is, since I know I'm replacing the compressor and hoses, any suggestions on upgrades to the system while I'm at it? Should I just get a rebuilt or factory-similar compressor or is there a better aftermarket option? Also, I've seen some interesting new thermal radiation technologies (fins and what not) to improve on the basic condenser. Anyone seen one of those for the 351W? Appreciate any suggestions to help me get the most chill for my buck.... Link to comment Share on other sites More sharing options...
85lebaront2 Posted July 23, 2020 Share Posted July 23, 2020 The later (1994 - 1996/7) underhood system will mount to the 1984 firewall. Wiring location changed in 1987, but that is not a major problem, Gary Lewis addresses it in his Big Blue thread. He is keeping the older condenser (1990), I used a new 4 Seasons one on Darth. Where the problems come in are the compressor and lines. The 1984-87 (I believe that is the change point) use the FS6 compressor, the later trucks use the FS10. The FS6 has what is referred to as "axial mounts" meaning meaning the mounts run parallel to the shaft, they also use a V-belt drive and the belt tension is adjusted by moving the compressor in it's mounts. The FS10 is a "tangent" mount which means it has 4 bolts that run tangent to the shaft, they also use a poly groove belt and on the 302/351 engines is a serpentine belt system using a reverse rotation water pump. This would require a complete replacement of the timing cover and all accessory brackets and pulleys (good point, the 3G alternator is used with this system). The AC line connections at the compressor also changed, FS6 uses service valves and O-ring seal screw on fittings, FS10 uses a block connection with the high pressure and suction lines integral to it. Aftermarket, Sanden makes a nice compressor and it is popular on street rods, resto modes etc. A company called "vintage air" makes some very nice kits using the Sanden compressor and has some lines available along with components to make lines. I did initially do a conversion from R12 to R134 on Darth, using all the original components and it cooled quite well with the exception of a hot restart where it would take a bit to get cool. This was more due to the design of the system, the poorly sealing blend door and uninsulated evaporator case (underhood) and once everything cooled down again it was fine. Hope this helps. Link to comment Share on other sites More sharing options...
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