Probably already been asked, but AC question

[jthebigjay]

I rebuilt the system on my 99 4 door Tahoe with Rear AC. new compressor, orifice tube, 3 cans of freon, 1 can of oil, and drier about 6 months ago.

All of the sudden the rear AC evaporator spring a leak *caused by the clip that holds the expansion valve on rusted out and rubbed a hole on the evaporator*. So i ran a can of Super Stop Leak through it with no luck. Replaced the rear evaporator today. Pulled a vacuum, put 2 cans of freon in, and now the front is blowing warm and the rear is ice cold.

But the sticking point is that when i leave both blower motors on low or off the Low pressure drops to about 20-25 psi. When i turn both fans on high, it pegs out around 60 psi.

Am i just 1 can short of full charge or did the super stop leak plug up my orifice tube or front evap?

I'm stuck and don't want to burn another $20 can of freon on a hunch or put too much freon in and loose anything i've already fixed.

Just looking for some advice.


ttt

Jay

 

[SunlitComet]

It sound like your front evaporator orifice tube got plugged. Do you happen to have a high side reading?

 

[jthebigjay]

HIgh side was holding about 225. I went a head and put another can in yesterday for the hell of it, it helped some, but not near as cold as it was before.

I guess i need to find a shop with a freon recovery system and get them to evac the system and change the orifice tube.

With freon going form $9 a can to almost $20 down here in the past couple of weeks, its not work loosing all the freon i have in the system.

 

[SunlitComet]

It sounds like the pressures are in the normal ranges. I don't suppose you got a thermometer that can clamp on to different parts to take reading or maybe an IR one.

 

[jthebigjay]

I guess my diagnostic question is that is it normal for the low pressure to jump up to near 60 with both fans on high but then drop down to 25 with both fans off but the high side doesn't move during this swing?

I"ll hook the gauges back up when i get home and pull some temps.