Found the post. This is the 3-way valves. (http://www.valvestore.com/products.asp?dept=1549).
Looks like they will be about $40.00 eack "ouch". Maybe cheaper some where else or just do the 1 ball valve + one "T" fitting.
By the way, my old 51 Chevy pickup came stock with the valve to cut coolant off to the heater in the summer. What a great idea. This will allow you to use the outside vents without air on days when AC is not needed. That is why we neeed the AC on most all the time even when just pulling in outside air.

 

You'd need 2 of those instead of 3 regular right?

 

Not sure on yours but as I see it on 5.9's, one on the in side (toward the heater core) and then either one on the out side (from the heater core) or a "T" on the out side. Should be the same on yours I'm thinking. I agree that I would have to have the bypass system as my truck has an auto.

 

After measuring the ac temp on a few trips with the valve either open or closed, I'm only seeing at most a 2 degree difference. Yes it helps, but not much. Is it worth cutting off water flow out the back of the head? I think not. I would recommend a bypass circuit of some sort if you are going to do this.

 

Yea, I have been following this thread to see if anyone would actually post what the temp difference is - Thanks! I did not think it would be much as my truck will get down to 40deg on recirc @ the vents which is right where you want it to be, it just takes a long time to cool down these large dark colored cabs after sitting in the sun for awhile. I used to do A/C work and if you got them much cooler then 40deg. they would freeze up on a humid day even here in Virginia.

 

I see on average, 8 - 12 degree difference in my dry climate. I have a " T " setup to keep the fluid flowing to the head, I open the valve every other week er so, to keep the fluid from becoming stagnent. ..

My AC is a joke with a Giant leak somewhere . . . But when filled it will show low 20's

 

I'd love to have 40* at the vents. Right now, I run about 56-60* at the drivers vent on recirc. Full charge on the A/C and the shop can't find anything else wrong.

Although I have noticed it will drop closer to 50* when idling, then it runs back up closer to 60* when I'm on the road.

 

I was gonna do this mod but my "New" early 04 truck actually has the best A/C of any of the Dodge Rams I have ever had. It starts blowing cold within 30 seconds and I will have to turn it down within a few minutes because it starts getting too cold.. N"ICE"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

I gained about a 6 degree delta on Recirc with the ambient at 95 degrees. Before it was 44 degrees and with the valve closed it's 38 degrees. That makes a big difference in our SE Texas hot and humid climate.

MikeyB

 

me too. i will have to stick a thermometer on it now just to see exactly how much lower the temp is. i never checked it before or after, because i knew before the mod the temp was ridiculously high. i would have to run the a/c on high the entire time i was in the truck and still was not comfortable. now i run it on high for 3-4 minutes then switch it to 1st or 2nd fan speed. the air is MUCH colder. so i do't really care how many degrees it changed. i just know now i am comfortable apposed to before the mod. a lot more than the 2* that was talked about above. like mikeyb said, it makes a major difference in the Texas heat!

 

You should never design the system to have temps below freezing. The moisture inthe air will condense out and freeze on your evaporator. Then you'll lose all A/C when your evap turns into a block of ice.

 

Yea, that was what I was trying to get across in my post above, I have gotten systems down to 35DEG and had them come back from freezing up during humid conditions. Whatever your output air is on recirc the evaporator is 4 to 6 DEG colder on the surface so that is why they freeze up in high humidity, if I could get a system to 40 in the garage bay I knew it was where it needed to be....

 

I noticed on my road trips last weekend the AC froze up after about three hours. So I had to take a break and let it thaw out. It's a drag that my passenger side blows about 25- 40 degrees warmer than the driver side. so the truck never really gets cold.

 

Your truck is low on R134a. That should fix you up somewhat, well as good as the design is which isn't too good. LOL

 

I fill it every other week, with the small can from the auto parts store . . . its a real PITA . .