No need just open the valve every so often during the summer to stop stagnant fluid.

My A/C gets almost freezing in my cab with this trick that tells you how much hot air is leaking in from the heater core.

 

Very true.. I might just try it out.. I already have the lines spliced where i back flushed when I flushed my system out.. the only other question I would have is what kind of pressure increase is being caused there as the Heater core system also acts as kind of a bypass as well. I know the Therm has a small little hole there with a piece of brass there but not much of a bypass not like what I'm used too on the old fords.. though..

 

I don’t think there is any worry about back pressure it was more speculation. When you think on it the first 15 minutes as your car warms up the system is blocked by the thermostat if it can take that it can take cutting off the flow through the heater core.

I tell ya my A/C is so much cooler with the heater core flow cut off its great.

If you are worried get two valves and block the in and the out side of the heater core with this you have no pressure in the heater core at all.

 

My cab vents are still not flowing as good as I want I noticed I still need the window down a crack just not as big a crack so I drilled me 4 more holes. Now I get a very small amount of cabin pressure but don’t think I need the window open at all… YES.

That’s going to be nice no more needing a window open all the time like the last 14 years.

 

At the very least.. iiiiffff*** by some chance it was too much pressure i would just open the little tiny hole up bigger on the thermostat. No biggy.

I went down today to Lowes as Sears and Ace did not have anything. I got some PEX shut off valves that are brass? Metal? Anyways.. I couldnt find any other kind that would work.. tried the 3/4 inch in a 5/8 ID tube they had and with a little spit.. i could force it in.. with that and the clamps should work fine.

I'm going to try this out.. Anything to get a little better AC is worth a shot.

 

You will see a 10% to 20% improvement in cold air coming out your vents be prepared you may be surprised at how cold it can get without the heater core flowing.

 

Did you block off both hoses or just the "In" line that is going from the intake manf. to the core?

 

just the one I put the valve on the in hose the flow going into the heater core.

 

This might even help with Temps very slightly.. You know.. its taking hot engine fluid off the engine.. pushes it through the heater core.. and when not in use.. its simply passing the fluid back to the water pump that pushes it into the engine mixing your coolant coming from your Rad and that already heated coolant.. if you can understand what the point I'm trying to make.

I have not tested it yet.. I'm waiting on getting a new fan blade for my Clutch from a Jeep Liberty..

 

Oh also I was talking to my dad how my temps rise about 10-15 degrees when the AC is on... He was telling me that's a little high and things my Hi-pressure side has too much pressure.. he was telling me it will cause my cooling to be **** poor as well as cause engine temps to rise as it causes the condensor to become super hot.. more than normal which is not allowing the Rad to cool down cooler.. Like driving in 100 degree weather when its really only like 80. If you know what i mean. I still havent checked it but thought it was worth throwing out there..