I did the mod as described in the original post about a year ago. I replaced a shut off valve in the heater inlet hose with the valve out of the Ford Ranger. I didn't like the water and coolant sitting in the heater core uncirculated for 8-9 months out of the year and this valve lets me open up the core and circulate the water from the drivers' seat.

It does a great job of making the vent, AC and Max AC settings much cooler and more efficient. I have to be careful on the highway unless its really hot outside or the AC is too cold (which is a great problem to have south of Houston on the Gulf Coast).

Personally, it was a very easy and great mod for me. Lots of ways to do this but I do like this one!

 

So my '02 already has the cut-off valve when Max AC is selected. When you go to any other setting, it opens the valve, so there's no issue of coolant sitting in the core for 8-9 months unless you never take the selector switch off Max AC (assuming the valve closes completely, of course). So far, no complaints about my AC (on Max) either. However, I read somewhere that the stock valve doesn't close it off completely -- is that true??

 

I've probably only used my heater a dozen times in the past 8+ years. The approach suggested by Markadeck of "just stopping it at the inlet and calling it a day." would be the easiest for me. Does anyone see any problems with this approach if I can remember to open the cut off valve and run the heater a couple of times a year to flush it out?

 

I don't think it'll cause any problems, Ernest. Plenty of folks run it that way, with just a simple manual cutoff valve.

 

Diesel Site says that the stock setup on the 99-03 7.3's and 03-06 6.0's does not shut off completely. Also, the setups in the Excursions are reportedly "shut-tight" configurations.
http://www.dieselsite.com/index.asp?...RODGROUP&ID=15

 

Is this the reason why when im parked and i have the it on max ac the air goes cold then warm then cold then warm etc.

 

Sounds like that might be correlating with either your compressor kicking on and off or the thermostat opening and closing on the engine... I would guess the latter of the two.

 

That's it. I am ordering the DieselSite kit and doing this right after my tank mods in a couple of weeks. Anyone that lives anywhere near Houston (I am 30 miles north) knows how important and how much of a good friend cold A/C is. You sold me. No such thing as "too cold".

Thanks.

 

Hey Scott... I lived for 9 years in Beaumont and drove an old '85 F150 25 miles to work and back every day. Problem was that the truck came from the factory with no air conditioning at all. Believe me, I know the value of cold air in SE Texas summers. I'm going to do mine when I do my water pump in the next month or so (assuming the pump lasts that long).

 

Hey Pete!

We make the run to Beaumont occasionally for Cory Morrow shows downtown. Also go through there on our way to Lake Charles for weekend getaways.

Can't imagine not having A/C in SE Texas.

 

Lots of ways to skin this cat - the key is keeping the hot water out of the AC airflow however you're most comfortable. I didn't know about the dieselsite valve and I like the Ford Ranger valve I put it. I've also done it with just shutting off the hot water like I said.

But like the rest of the guys in the south, no AC is too cold when its 100 degrees and 100 percent humidity. Gotta have a good AC and big glass of iced tea.

 

Guys, the $2 manual valve works great. I used it for 2 years and never had a problem. But my 3 year old would ask me to turn on the heater in the 50ish weather, when I normally am perfectly fine. The inconvenience of having to tunr the vlave on and off really made spending the $40 for the dieselsite valve a no brainer.

If you are gonna do it, I have to say to just so it right the first time. Get any kind of valve that is vacuumed controlled with your panel. That way you only have to pop the hood when YOU WANT TO.. LOL!!!

 

YOU COULD USE THE VALVE KIT FROM DIESEL SITE (oops caps) and just tap it into the vacuume line that nlemerise used with his system. I think that I'll go the autozone route and save a few $.

 

i did this mod and it is great!!! the reason u cant use just the two dollar shut off is because some mornings u need heat and in the same afternoon u need air, also they told me that the coolant would stagnate sitting in the core for 6 or seven months..
i have a digital thermometer that stays in my vent and sometimes idling it gets as low as 39.1 degrees.. before it only got down to around 53.6 degreees
it is not hard at all to do this mod...
here it is.......

http://www.forgotton.net/diesel/heaterbypass/index.htm


trust me this works and it took me about twenty or thirty minutes to do
i bought the valve on ebay for around seven dollars
the whole thing probably costed less than twenty, maybe even fifteen

 

make sure you get 5 feet of 1/8 in. vacumm line, an 1/8 in. tee, and get a pack of the little rubber adapters to fit different size vaccum lines ask for them at auto zone, cause you'll need em.. 4 5/8 hose clamps
i folded the glove box down and cut the red vacuum line and teed it there...there is a little rubber plug that goes thru the firewall in the far right corner just above the carpet, poke a hole in the plug and feded the line thru it, then just fish it right up there where you need it...
this is probably my favorite mod that ive done, but i like teeth breaking ice cold air