Automotive Air Conditioning Information Forum (Archives)

rgnprof on Sat July 02, 2011 3:39 PM

Year: 1993
Make: Ford
Model: E350 Motorhome
Engine Size: 7.5L
Refrigerant Type: R12
Country of Origin: United States

'93 Ford E350 - A/C colder at idle

Postby rgnprof on Sat Jul 02, 2011 9:53 am
I recently recharged my motorhome A/C (Ford E350 460 motor) - had some leaking orings, but other than that everything looked ok. I pressurized the system to test for leaks before drawing a vacuum for well over an hour...

I had plenty of R12 so I went back with that...left OK 2 1/2 weeks ago and used the A/C on the way out of town - cooled ok, vent temps in the upper 40's, but it leaked on the passenger side floorboard - I can see the condensate dripping down from the evaporator, but I can't find the drain to unplug it. Didn't need the A'C in Montana...

Came back into town yesterday thru KS and OK - very hot! Outside temp 100+ degrees - vent temps run about 78 at WOT and drop to around 60 at idle. I think I am slightly undercharged - I can't exactly remember the pressure readings - or the ambient temp when I charged it several weeks ago, but I do know that I added about 4-6 ozs less R12 than the system called for...

Any ideas about the condensate drain and the weird increase in vent temps at idle?? My experience is that it is usually the other way around - vent temps decrease while cruising.

ryan

TRB on Sat July 02, 2011 10:42 PM

Why the undercharge?

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rgnprof on Sun July 03, 2011 10:03 AM

I think the pressures were good where I was at...so I didn't start another can. I am gong to double-check them again this week.

JJM on Sun July 03, 2011 2:10 PM

Cooler at idle likely because the system is running continuously, where as at higher speeds the system is short cycling, due to low charge or poor airflow over the evaporator. You need to charge by weight, not stop when pressures look good, since that could mask other problems.

You need to unplug the evaporator drain. Could be a lot of muck in there, restricting air flow and again causing short cycling at highway speeds. After nearly two decades. it probably wouldn't be a bad idea to give the evaporator a good cleaning. You'll probably see an immediate increase in cooling performance.

Joe

When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com

rgnprof on Mon July 04, 2011 1:49 PM

Thank for the help - one question - what's the best way to clean the evaporator? How do I get to it on this Ford E350?

ryan