E350 Dash vents blow hot

[ebflow]

Originally Posted by SheepShagger

Is this what you mean?
MAX AC ASSIST AC Control Valve for 1994-2003 7.3L

Is states 7.3psd but it's valid for a lot of vans also. Stops the coolent flowing into the cabin heat exchenger.

If you are going to do it, I personally think this is a better way, as rather than blocking the flow, it bypasses the core completley.
Heater Bypass Mod: Cooler A/C! - Ford Truck Enthusiasts Forums

I did the MAX AC mod from Diesel Site. Works GREAT! no more warmer air issue. Plus the AC is SO COLD! Installs above alternator in the coolant line, on the left side of the tee.

[scummy]

Glad to hear this. I just received mine in the mail, just need to find time to install it. Did you have to drain the radiator?

[ebflow]

I did have my radiator drained for other work. But I wouldn't imagine it would loose much. Just make sure to clamp hose left side of cut and should be fine.

[scummy]

So I installed the maxair and hooked the vacuum up to the blue tube in the dash, but I only get air blowing through the defrost vent. Is That the right one? I chose port 4 (blue) per Scalf77 recommendation which gives you vacuum in vent, A/C, and MaxA/C.

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[Scalf77]

Did you put a T in the line, it just T's into the blue or Port 4. It should not change the vent's.


-greg

[scummy]

Originally Posted by Scalf77

Did you put a T in the line, it just T's into the blue or Port 4. It should not change the vent's.


-greg

Yes I put a tee in the line. As soon as I do, I only get air through the defrost vent. When i take the tee out I functions normally.

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[Scalf77]

So i guess I would suspect a cracked hose or a problem with the airmax valve.
The vacuum is no longer getting to the vacuum control motor for the floor/panel door, so I would suspect a leak.

-greg

[scummy]

Ok, the Airmax valve I received had two issues going on with it. First was there was a vacuum leak in the hose they sent with the kit. The second issue was there is a plastic welded seam where the butterfly valve is installed that was not completely welded or failed, and left me with a good sized coolant leak. I called Dieselsite and they sent me a new one right away. Got the new one in and all is well. I now have no more heat in the vent position and my A/C works much better. Thanks for all of the help.

[JWA]

The key issue to this situation is completely blocking the warm coolant flow from the cabin heater core. Assuming the blend door, its drive motor and the control switches of the electrical system are functioning properly. If any of those devices aren't work to design temperature control and A/C efficiency is greatly reduced.

The link to articles on FTE are the best approaches IMHO. They use the least amount of parts and tend to be very simply for more DIY's to accomplish.

FWIW there was a time I'd bypass a leaking heater core to avoid doing the repair and still drive the car for the time being.

This warm vent air vents (no A/C selected) is aggravating to be sure---glad to see most of us can still provide how-to-repair guides for a cure!