Automotive Air Conditioning Information Forum (Archives)

bob234 on Mon May 23, 2011 3:10 AM

Year: 1994
Make: Chevrolet
Model: Silverado
Engine Size: 5.7
Refrigerant Type: R134a
Ambient Temp: 96

Just picked up a 1994 Silverado dirt cheap that had a A/C with poor cooling despite being fully charged. Had it evacuated, and went home and pulled the orifice tube. This is what I found(pic below). I replaced the condenser, compressor, manifold hoses, and the accumulator. I also flushed the liquid line and evaporator, then took it to a shop for a evac/recharge. Blows ice cold now even in 100 degree heat. I installed a Seltec in place of the R4 as I hate them with a passion.
Isn't this the worst black death orifice tube you have ever seen?

bob234 on Mon May 23, 2011 3:23 AM

The orifice tube I put back in the system after I repaired it was the standard white one. I think the old one was white at one time, but a variable one which I didn't feel was needed.

GM Tech on Mon May 23, 2011 8:06 AM

The OEM orifice tube is condenser mounted and is black to designate it is built backwards- the tabs are on the opposite end from a standard evap mount which is white. So did you use an evap mounted OT in the condenser outet? If so you have made a classic mistake- I have pulled out the white ones that "Ace" mechanics have stuffed into the condenser outlet- which was causing cooling concerns, see- they don't seal properly if you don't use a condenser outlet specified OT.

That "black death" you describe is just about normal for a worn out compressor- did you notice the OT plastic housing is black? Black death has become a wide spread term to encompass almost all failures. I use black death to describe overheated, melted teflon, that has rehardened after it cools- from Ford SP failures.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......