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another 94 suburban question

jtstoney on Sat June 07, 2008 9:11 PM User is offlineView users profile

Year: 1994
Make: Chevy
Model: Suburban
Engine Size: 5.7
Refrigerant Type: 134
Ambient Temp: 95
Pressure Low: 50
Pressure High: 250
Country of Origin: United States

This truck, has never had sufficient cooling in the rear ac unit since day one.

I recently replaced the front evaporator and everything forward after a compressor bearing started to squeal.

Pulled vacuum and charged with approx 55 oz of R-134a, and ran a leak test. System is still short 9 oz (64 oz required) as of today, but no leaks detected.

All tests today were at 95 F ambient, 75% humidity

Front unit running only, 50 low, 250 high, 70 degree F vent at 2,000 rpm.

Front and back running, 45 low, 289 high, 70 F front, 80 F back at 2,000 rpm

Something doesn't seem right with the temps vs pressures, and I don't want to top off the system if I'm going to need to open it up again.

I'm afraid I'm going to have to replace the rear TXV, just a feeling.

Felt the lines into the unit in the rear, only slightly warm. Line out of the rear is slightly cooler than ambient.



Edited: Sat June 07, 2008 at 9:17 PM by jtstoney

TRB on Sun June 08, 2008 2:04 PM User is offlineView users profile

You need to get the proper amount of refrigerant int he system to have a proper diagnostic test. If it not leaking fill it up and get back with us.


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