Should AC air out of vents be colder?

[Pinky 1352]

2003 Expedition XLT 4.6L 2WD with front and rear air/heat with manual control.

My previous post mentioned that I *finally* got all new AC parts installed (front and rear), and now we also have any and all leaks at connections found and fixed.

My problem now is that the air temp coming out of the front vents still leaves a lot to be desired.

For reference, today it was 95 degrees late this morning with 25% humidity.
And parked in the shade, with only front AC engaged (after car had been running with recirc) and I'm getting a paltry 60° out of the front center vent. If I also turn on the rear air, it raises to 65° at front vent, and then is also 65 at the rear ceiling vent.

I've had to go thru 3 mechanics/shops to try and get this all right, with the last to work on it being PepBoys.


They *supposedly* vacuumed the system and refilled.

With these gauge readings with both front and rear AC on, a neighbor is telling me I may be a little short on freon?


What do those knowledge here think?


Does it need a bit more Freon, or did they maybe not do a thorough enough vacuum (because at this point who knows how much oil may have been put into the system when the other two useless mechanics worked on it!)?

I'm almost certain that when I first bought the car a bit over a year ago, and they AC worked for a short time, that I was getting sub-50° out of the vents.
I'm in Las Vegas, and if 60°, at idle in the shade on a 95° morning, is the best this thing is going to do, it's going to be very unpleasant when we got those 115° days and I have to drive in the sun!

(When I left PepBoys yesterday, I was seeing somewhere between 60-65° during street driving, a steady 60° on the highway, and creeping near 70° while stopped at lights!


I went with PepBoys because they at least guarantee their work for 90 days, so I'll be going to them for whatever this needs now.


See pic for gauge reading after a half hour of running in the shade, with front AC set at speed 2 on blower dial for front vents, and full speed for rear AC vents.


TIA for any suggestions!

 

[dmpaul4691]

I'm having a similar problem. Going to try cleaning the condenser and evaporator and see if that helps.

 

[chuck s]

30°-35°F below ambient temperature is all car AC can normally deliver. 95° day expect 55°-60°F air out of the vents. 115°F day? 80° is about all you can expect. This differential works on ambient temperature so recirculate (MAX) is necessary. The lower you can get the inside temperature the lower the AC can make it.

Thought just occurred to me that if the outside air is less hot (hard to type cooler) than the inside air from a closed car the AC may be able to supply less hot air out of the vents for a while that recirculated air. Never tried it but I have found opening all the windows and the roof does help at first.

-- Chuck

 

[SafariGoneWrong]

This is from my 2006 Ford Expedition Service Manual, Volume I: For a 95 degree day, discharge pressure range is about 180-260 psi and the suction side is 35-74 psi. Ford says to check with all windows and tailgate open, blower front and rear on high, outside air (versus recirc) and temp selector at coldest setting.

On my 2006, "Max A/C" turns off coolant flow to the heater core (both front and rear I think per the wording in the manual). Check operation by watching the valve in the heater hose just forward and right of the air cleaner. It stays open in all positions but Max A/C. You'll see the lever move if it's working. There's quite a difference in my '06 between Max A/C and non-Max A/C.

Your pressures seem reasonable. I suppose your blend doors/actuators are working as they should. I feel your pain.

Some trivia:
-Pressure Cutoff Switch
Open 455-495psi
Closed 295-355 psi
-Low Charge Protection Switch
Open 9-11 psi
Closed 16-24 psi

--Dave

 

[Dustin Gebhardt]

Your vent temperatures seem high. I routinely see vent temperatures in the 40's while highway driving, ambient weather is about 90'F with humidity in the 70s/80s (Oklahoma summer). Yet your pressures seem reasonable, although perhaps the low pressure is a bit high, but not by much. This could be a slight overfill of refrigerant, or a poorly performing evaporator. You say that you got all new parts. Does this include the evaporator?

As mentioned, your blend door could also be opening the heat side and allowing the hot air to mix with the cold.

 

[Dustin Gebhardt]

In my '07, I can drop down the glove box and see the evaporator box. I drilled a small hole in the box and I sometimes use an instant-read thermometer to see what the evaporator box air is reading or use a boroscope to see if the evaporator is icing over or covered in crud. I also use this hole whenever I need to run some coil cleaner spray. When not in use, I cover the hold with some aluminum duct tape.

 

[getdealtwith]

Ford A/C Quick Tips #6: NEVER use Static Pressures for Diagnosis

A quality R134A Gauge Set is a must for an accurate Diagnosis-http://amzn.to/2bwIij6In this video we go over how misleading these readings can be.My Company ...

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