Low side normal /high side low stumped

[tbirdtbird]

Is the engine fan shrouded?

There are no auxiliary electric fans in front of the rad?

[JohnHere]

By fans you mean the fan on the engine yes it’s pulling plenty of air as well as the cabin blower motors . And I did charge it with both front and rear on max settings the blend door is working and so is recirculate

Yes, the fan(s) on the engine. So all of that sounds good.

The low-side pressure you last measured was in the upper 40's, so I'm beginning to suspect the orifice tube. Do you recall whether the OT you installed had a main body that was red in color? If so, it should be the correct part for your vehicle and have an orifice of 0.062" according to Ford. An incorrect OT having a larger orifice than that would tend to raise low-side pressures above the optimum range and result in higher duct temperatures.

Did you install it in the right direction, with the red side and longer screen pointing toward the condenser? Were the o-rings in place on the OT itself?

[Excursion2001]

Is the engine fan shrouded?

There are no auxiliary electric fans in front of the rad?

Yes it’s not cracked or anything and it’s only mechanical fan that’s it

[Excursion2001]

By fans you mean the fan on the engine yes it’s pulling plenty of air as well as the cabin blower motors . And I did charge it with both front and rear on max settings the blend door is working and so is recirculate

Yes, the fan(s) on the engine. So all of that sounds good.

The low-side pressure you last measured was in the upper 40's, so I'm beginning to suspect the orifice tube. Do you recall whether the OT you installed had a main body that was red in color? If so, it should be the correct part for your vehicle and have an orifice of 0.062" according to Ford. An incorrect OT having a larger orifice than that would tend to raise low-side pressures above the optimum range and result in higher duct temperatures.

Did you install it in the right direction, with the red side and longer screen pointing toward the condenser? Were the o-rings in place on the OT itself?

I can’t remember the color I have the part number 38639 OT . The guy that I was talking to on my diesel forum said that this OT works better I don’t know it is supposed to he sweared by them in making colder ac , I have the factory one still in packaging. I did put it in long end sticking towards condenser . I looked up a video on how to install it just so I made sure not to screw it up . But why would my low side drop in pressure and my high side go up in pressure when I raise the rpms up ?

[Tim]

It calls for the orange OT, the same as the part number listed.

[Excursion2001]

It calls for the orange OT, the same as the part number listed.

The factory one from Ford is like a dark red

[Excursion2001]

An incorrect OT having a larger orifice than that would tend to raise low-side pressures above the optimum range and result in higher duct temperatures.

Slightly OT (as in Off Topic ). Pretty interesting. Even a smaller than normal one will raise duct temps, but due to a starved evap this time. And, paradoxically, the evap may well progressively freeze up due to the lower than normal suction, beginning from the inlet where that little amount of liquid is able to boil. Metering devices are very delicate equipment. With TXV equipment, a field manual will say things like "valve closes too narrow than specified" "valve opens too wide than specified" once proper charge level is assessed.

So I should put the factory one back in because the different OT will cause the txv to function different?

[JohnHere]

It calls for the orange OT, the same as the part number listed.

Digging into this a little deeper, there seems to be conflicting information on which OT is correct for the 2001 Excursion. My local Ford dealer lists Part Number 38639 as the red OT with a 0.062" orifice while others list the same Ford part number as the orange OT with a 0.057" orifice. Which one is correct? I don't know. However, on this vehicle, it seems to me that the orange OT would reduce the low-side pressure somewhat and lower the temperature of the evaporator (and vent temps).

[Tim]

Industry cross seems to be wrong on more than one site I just checked. From Motorcraft. YG346 is red.

fordred.jpg (166.37 KiB) Viewed 4835 times

[Excursion2001]

Industry cross seems to be wrong on more than one site I just checked. From Motorcraft. YG346 is red.

fordred.jpg

Should I put the red on back in ? It was 83 degrees this morning and my ac could only drop to 62