I know with the heated water passing thru the core and the blend door closed the heater box itself gains heat ... so with that going on the A/C air must overcome the heater box ambient temps inside!!! That is why I installed the by-pass valves. To get maximum cold temps from the A/C I covered the "cold" line out of the compressor going to the heater-A/C box, with appropriate sized foam pipe covering (Home Depot/Lowe's) to retain as much "cold" as possible ... and it's working !!!! Dave !!!

 

Bingo!

Simply allowing the A/C to work its' magic....That's all..

 

im getting 28 degrees at my vents.the thing will freeze ya.

as long as your blend door works good,there's no need for a bypass valve.i don't have one.
just wrap the entire heater box and make sure you hear the loud THUD when you turn the MAX A/C and have a properly charged system.
wrapping that heater box dropped my temps big time.i was getting warm air all the time at the vents.now i feel the true outside air.when i drive down through a cool shaded valley i feel the cooler air driving through when i have VENT selected,were i never did before..........then i charged the a/c and now i just freeze.
the stuff i used:
EZ Cool Automotive Insulation heat barrier and noise reduction for cars, trucks, classic cars, street rods and much more

pay no attention to the check valve.i posted it for my mechanical to electrical vac pump swap originally.

 

Thanks for the linky!

Would one of the hood insulation panels for the diesel trucks be of use to me?

Just trying to contain the heat, etc...

Also..What about header wrap?

 

That cold line coming ot of the compressor going to the A/c box is actually refrigerant returning to the compressor from the Evaporator(A/C Box). You may actually be shortening your compressor life.

The refrigeration cycle works like this:
Low temperature/low pressure gaseous refrigerant enters the compressor
Refrigerant is compressed and discharged as a high pressure high temperature gas.
From there it goes into the Condenser where it is condensed into a low temperature high pressure liquid
A short stay i the reciever/dehydrator and it is on to where the Magic happens.
The TXV/Orifice Tube. Here low temperature liquid is converted into low er temperature GAS through the magic of PTR( Pressure temperature Relationship)
Next is the Evaporator(A/C Box). Here the low temperature low pressure refrigerant picks up heat from the air and is sent back to the compressor.

Now hopefully everything is working correctly and there isn't any liquid refrigerant leaving the TXV/Orifice tube and it is picking up enough heat in the EVAP to change any liquid to a gas, but id not that is o.k. because thesuction line going back to the compressor will allow it to pick up some supreheat to make sure no liquid makes it to the compressor. Because we all no how incompressable liquids are.

So you see by adding extra insulation to the cold line between the A/C Box and the compressor you may be allowing the compressor to be slugged with liquid refrigerant

Matt

 

So my idea of keeping the "cold" in that line is all wrong .... "well I'll be dipped" that just showes how much I didn't learn when I skipped A/C class. My thought was to finish the job that the factory didn't !!! So you would recommend removing the extra covering I installed in the areas where there was none. There are some areas along that line that WERE covered, but that insulation has turned to stone and fallen off.... would it be OK to leave that section covered ???
My truck was converted to 134a by a professional about 3 yrs ago. The only issue has been the screw-on conversion adapter for the high side had a schreader valve start seeping, so we put the red cap on tight stopping the leak and the complete adapter was just replaced about 2 weeks ago !!!
Thanks for the info for the uninformed DUH !!! And, Lord knows we NEED our A/C here in the Nevada desert... our average high this time of year is 104*.... but it's a dry heat ... Dave

 

Yes you can do with out the extra insulation. The only reason you will see insulated on refrigerators and parts of the home a/s is to mitigate condensation where that would be bad, like your attic where mold can grow. It is not as much of an issue under your car because it will just drip on the ground.

Matt

 

Thanks Matt, I got it, geeze, now I have another project to do I hope the others viewing this thread learned a lesson in A/C too. The camers in my phone is being a P.I.T.A. otherwise I would post some pictures ... Sorry !!! Dave

 

I am glad I could help. As far as insulating the air box, the more insulation the better, Engine compartments get hot, and that heat transfers right through adding heat load. Another thing you can do on these older trucks is to check the iar side of the evap. These things didn't come with cabin air filters so it wouldn't hurt to clean the evap.

matt

 

I dont know what the issue is, My truck blows 34.4* air at and IDLE and even colder when driving

 

I used a meat thermometer in the vent closest to the D/S door in mine..

39* at Idle...Max A/C and the foam is missing between the ductwork...


I have another dash to swap in, and I'm wanting to insulate the ductwork on it....

 

Well I just reinsulated my evap and fan housing, using that foil faced stuff. I also moved the vac switch to the firewall to lose a bracket. I'll let you know how it works out. I'll send pix once I get enough posts.