On Big trucks you have to order the truck with the water shut off valves (i used to work at freightliner and it was an option when specing a truck). this has been by far the best and cheapest mod done to date. My buddy and his girlfriend rode in my truck tonight to watch fireworks and he even made mention of it being cooler and he has not ridden in the truck in several months.

 

Some numbers for today. Ambient at 93 degrees running 65mph on the highway. Vents set to outside air the driver side register temp is 40 degrees. Vents on recirc the driver side register temp is 38 degrees.

Good enough for me!

MikeyB

 

THANKS MIKEYB, I love my truck even more now!!!!!!!!One of the best mod's I have done. My fingers are blue now and I love it.

 

I'm figuring theirs no reason you can't, but you could do this on a 92' also I would guess right?

 

How about a 2002 24V?

 

would probably work the same as the 3rd gen. git r dun Roper and let us know.

 

I will go get the goodies today!

 

I don't do a whole lot of driving in my truck but the A/C seems adequate to me, even in 100 degree weather I'm able to keep fairly cool when in recirc with the blower speed at 3/4 even driving thru the city.

Anyway this mod sounds great and I love a reason to mess with the truck, just curious if you could get some comparison numbers with it flowing like it did originally in the same conditions just want to know how much of a difference in temp we're talking about here.

 

OK, did the mod on the 2002 CTD. It did not have good AC before and I just did the one side but it made about a 60-70% improvement. When i moved the dial back over to heat, I could get some warm air, but by far it is BETTER.

 

All the old cars used a heater water valve - some were cable and some were vacuum operated. When I was doing auto AC work in the 60s I always checked the water valve condition by putting a thermometer in a diffuser and pinching off the water line with a pliers to prove if the valve shut off tight. In the early years of auto temp control the mfgrs still used a valve and let heater water flow in all the AC modes except for max cool. Then they eventually did away with the valves and did all the temp control with the dampers. Heater cores last longer cuz they don't fill up with sediment and corrode. All engines have a bypass built in somewhere to keep from deadheading the water pump before the t-stat opens. D & F did it with an external hose and C did it with a passage in the water pump. My 12 valve had an ext. hose bypass but I haven't looked at my 03 closely enough to see how they did it on the CR. Also, a lot of t-stats have a tiny hole next to the disc. One valve will stop flow thru the heater core but make sure it's in the supply. There's a LOT of pressure in the block til the t-stat opens and I wouldn't trust a heater core to take that high pressure forever. The outlet of the core is plumbed to the inlet of the pump so the core will only see suction pressure instead of discharged pressure if the valve is in the supply. I wouldn't use 2 valves without a pressure relief to protect the core. Also if the intlet valve leaked internally and the outlet valve sealed tight... there ya are with full pump head on the core. Craig

 

So does that mean you souldn't use 2 valves only the one on the Inlet side?

 

By doing this mod, does that mean you only get full cold, with no tempature adjustment.

I have to back mine off 4 or 5 click's to make it where I want or it get's too cold. Actually, I have to keep going back and forth. One click either direction is either too hot, or too cold.

 

I put shut off on a 1977 ford when the heater was leaking. cbrahs that was a good looking job. I am thanking of doing my D 3500. I thank I will use a three way so my water can still flow. I thank it will help cool.
new member as of 7-06-08

 

It occurs to me that anyone with a 5.9 and a Jake brake could use the vacuum pump for the Jake to put in a fancy valve. I wouldn't know how to do it, but I bet someone out there does.

 

Glad to hear that!

MikeyB