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compressor issue

italian_guy007us01 on Sun May 11, 2008 4:06 PM User is offline

Year: 1995
Make: chevy
Model: tahoe
Engine Size: 350
Refrigerant Type: r134a
Pressure Low: 75
Pressure High: 30

Hello
After replacing the receiver drier and filling with 4oz of double end capped pag150 oil, I vacuumed down to 30mmHG for over 4 hrs. When I went to charge, I charged liquid first on the high side with the can upside down and then I finished with low side as gas. However, the low side pressure inched up to 80lbs and the high side stood at 30. the compressor did not cycle on at all so I jumpered the wire at the accumulator to get it to turn on. While it was running, no suction or discharge from what I can tell. Clutch did engage however. At times while engaged, it seemed like the compressor drag was going to stall the motor. Im thinking this R4 is toast. If the compressor is bad, what options do I have as far as replacement. I see that a remanufactured and new is offered here on this site. Which route should I go?

Thanks
Ben

TRB on Sun May 11, 2008 5:11 PM User is offlineView users profile

Did you remove the connections on the condenser? Believe this is a year where both fittings are the same. Odd pressure readings is making me think the connections got switched. I always suggest a new R4 just because of the design of the compressor.

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bohica2xo on Sun May 11, 2008 5:24 PM User is offline

The static pressure differential looks like either a connection that is not depressing a schrader valve, or a nasty obstruction.

With a static pressure of 80psi, there should be no reason to jumper the switch. Switch jumpers sell plenty of compressors...

How long did you run this system with the compressor jumpered? You said it nearly stalled the engine?

What did the orifice tube look like when you pulled it before replacing the dryer?

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

italian_guy007us01 on Sun May 11, 2008 6:47 PM User is offline

Thanks for the replys so far. Believe it or not, I did not even attempt to disconnect the fittings from the condenser since I would have to disassemble the front grille assembly and that to me, seems kinda involved. I didn't even take out the orifice tube because isnt that located in the line which runs to the condenser? Honestly, I was just hoping to to R&R the receiver drier, vacuum down and recharge. As far as the conpressor looking like it was stalling the engine, it seemed like it had a huge internal drag which was placing more stress on the serpentine belt. In other words, what I am alluding to is the possibility of an internal seizure (if that is possible). If it matters any, when I pulled the old accumulator out, there was no oil in it..NONE...which I found strange because I was always under the impression that the accumulator held close to 3 oz of oil......dunno...
Jumpering the switch...well, after I charged the first amount through the high side, I thought that the compressor would have enough to kick on but nope....so, I took a short piece of 12-2 wire and jumpered it long enough so I can watch the pressure. Sure enough the low side creeped to 75+ and the high stood at 35-40..50 tops...and this reading was at 800RPM idle...revving it produced the same results.....
Also, I might add that I changed out the rubber o seals on the back of the compressor with new ones and also new green O-rings on the accumulator fittings (replaced the black ones)...AND blue nylog on everything......
prior to this year the A/C worked great until one day this yr i fired it up and no A/C. Also on that day, I was greeted with a loud, piercing squeal and some smoke....but I thought it was the power steering pump (it did have a bad leak). I just finished replacing the pump and both hoses so now Im tackling the A/C. This was my g/friends truck and I got it off of her and she claims that she had it charged one time in the past for 300.00...outside of that nothing else was done.
Further comments are always a welcome!

Thanks
Ben

bohica2xo on Sun May 11, 2008 8:58 PM User is offline

Looks like it is time for some new parts...

Your compressor sounds like it is dead. Smoke, high drag, no oil in the accumulator.

The serpentine condensor is highly suspect. The 2mm channels will trap the big pieces from the compressor, and it is not easily cleaned. I would spend the 130 bucks for a new condensor. A new compressor, cycling switch, accumulator, O rings, orifice tube...

Clean everything else well. If the hoses have mufflers, a new hose set too.

About 400 bucks in parts should have it working as well as new.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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