I have 1996 F450 7.3 want to know if I can put shut off in only one line in heater core and which one thanks Ray

 

Yes, you can do it. That begs the question, "Why do you want to do that", though. It would be best in the inlet line, but either line would work.

 

Not sure what Ray has going but pulling the heater hoses from the heater core and "looping" the coolant flow dropped the AC temp on my '84 a good 10*+.

A straight shut-off valve would make it simpler, but right now I'm trying to work out a way to set up an inexpensive three valve for the heater core (input off, outlet off, by-pass before the other valves on) so I can switch this easily.

Wasn't sure if I could block off the coolant flow to the heater core with no ill effects.

(LOVE those old "covered wagons"!)

 

FWIW, regarding my old 93 Exploder, Ford issued a TSB to install a vacuum-operated valve that would cut off heater core flow when in MAX. Seems that truck didn't quite cool the interior well enough until the heater core flow was removed.

Steve

 

Some Chrysler products used an H valve in the heater hoses that does just what you are describing. I don't remember which ones though. Look around, they were pretty common.
On that 450, the doors in the system under the dash should be enough to block airflow through the heater core if everything is working right. If a shutoff valve is needed, there's something wrong in that area. Your 84 had a similar problem. A shutoff valve shouldn't have been needed.
Maybe I'm being **** retentive, but I prefer to fix the problem than try to work around it.

 

Yep. I remember that one well. Ford came out with this when they discovered the Blend Door Actuators were getting flaky while they were still under warranty. It was easier to close off flow to the heater core than for them to pay for removing the instrument panel to replace the actuator.
When the actuators finally failed completely, the trucks were out of warranty. Pretty shady IMHO.
The Techs had mixed emotions about it. It was a really shi**y way to pass on the ultimate repair cost to the customers, but we were relieved to not have to pull all of those IPs for the meager amount it paid under warranty. Either way someone was going to get screwed, but it wasn't going to be Ford Motor Company.

 

I have a 2005 F450 and a 2008 F350, I have owned 3 rangers,3- F150s, 2- F250, 2- F350s , 3- E350s , 1- F550. I am currently in the process of returning my F450 under the lemon law. My F450 has only 7500 miles on it, I bought it new and started having problems with the heater the first time I drove it for longer than an hour. No matter what position I have the vent selector, or the temp selector, the heater is on and blowing hot air. if the vent selector is off, the hot air boils out from under the dash. After an hour the cab becomes unbearably hot and I have to open a window, or both windows. Ford has replaced the blend door actuator twice and another actuator once and the entire heater box once without solving the problem. Ford told me to run the A/C. As far as I know A/C is an option and the manual tells me to turn the temp selector to the blue "cool" side to recieve cool air when in "vent" mode. I am towing a 14,000 lb trailer and need the extra HP the A/C would use up. I run my F350 A/C all the time because it has a temp control system, but on really warm days on longer trips it barely cools, so I am assuming it has the same blend door problem. Ford just does not want to fix this continuing problem. The ford techs I talked to said the heater core is on all the time. I believe the heat from the core is warping the blend door, causing more and more heat to enter the cabin the longer you drive. I believe most of the A/C posts stem from the blend door problem causing the A/C to stay on longer than it should, thereby causing overheating of the system components.

 

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http://www.dieselsite.com/index.asp?...PROD&ProdID=21