S-10 Forum banner

1 - 20 of 21 Posts

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #1
Last season my air conditioner worked. This season not working. The compressor clutch is engaging and the low side of the evap is reading normal, but the high side is way below normal. It's at like 100 lbs. Does this constitute a bad compressor? Or could it be something else?:dunno:
 

·
Nice Jorb
Joined
·
3,146 Posts
The orifice tube acts as a filter and a restrictor of freon. After the freon passes through the orifice tube, it then reduces pressure and it becomes the low side as it enters the evaporator. If it's not restricting flow properly, then the pressure would, theoretically, be lower then normal on high side and higher then normal on the low side. It also wouldn't allow the freon to evaporate. If you're gonna replace teh orifice tube, also change out the accumulator for the sake of your compressor.
 

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #5
Thanks for the info. That sounds like what may be the problem. Initially the low side was a bit high, but I released some of the pressure. Is there any way of making sure that this is the problem? If it is where would be the best place to pick up these parts?
 

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #7
Okay....now where is the orifice tube? I took off the accumulator and thought it was supposed to be right there at the end of the hose but it's not. And of course the haynes manual says nothing about the orifice tube.
 

·
Registered
Joined
·
218 Posts
It is in the bottom of the evaporator, pull the lower line and you will see it there.
 

·
I da numba wun tunda!
Joined
·
406 Posts
if suction pressure(low side) and discharge pressure(high side) are the same and the compressor is running then the valves or piston inside are damaged. I doubt the orifice would be feeding too much because its just a little brass disk with a hole drilled in it(at least thats I think it would be)

I would have to say compressor because you said "low side was a bit high" which is a sign of the compressor not pumping
 

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #10
Well I replaced the orifice tube and the accumulator and it still doesn't work. So.... I guess the compressor is the next step. Any one know where to get it for a descent price?
 

·
Broke as hell....
Joined
·
195 Posts
There $98.** at Advanve autoparts rebuilt a new one is around $200.00. I just bought compressor accumulator and Orifice tube. Oh and has your truck been converted to R134a?
 

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #12
I replaced the compressor, accumulator, and orrifice tube and the damn thing still dont work!!! The comp cycles on and off but the high side pressure is still only 50lbs. Does that mean that there's some kind of blockage in the system?
 

·
Anybody got 20's?
Joined
·
5,731 Posts
bagdbug said:
I replaced the compressor, accumulator, and orrifice tube and the damn thing still dont work!!! The comp cycles on and off but the high side pressure is still only 50lbs. Does that mean that there's some kind of blockage in the system?
What exactly are both ot the pressures? What year truck is it? Does the suction line get cold and sweat at all? Are you checking the charge with the A/C on max and the blower speed on high? The compressor should not cycle on and off when it is set on max. If it does it could be the pressure switch.
 

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #14
I charge the low side to 45 psi. the high side reads 50. This is with the system off. With it on max, it does cycle on and off and the low side drops considerably and the high side raises to about 80-100. This is on a 97 s10 4.3
 

·
Anybody got 20's?
Joined
·
5,731 Posts
bagdbug said:
I charge the low side to 45 psi. the high side reads 50. This is with the system off. With it on max, it does cycle on and off and the low side drops considerably and the high side raises to about 80-100. This is on a 97 s10 4.3
Wait do you charge it with it running or with it off? You are suppose to charge the lowside with the system running set at max. The charge can be anywhere around 40psig to 55psig depending on temp. outside and indoor air temp. The suction line should be cold and sweating. With you driving down the road around 40mph and up it should read close 40* coming out of the supply vents.
 

·
Anybody got 20's?
Joined
·
5,731 Posts
And by them way I believe the metering device you have is not a orifice tube but a expansion valve. Also how did you evacuate the system after you got done installing the new parts? Did you use a vacuum pump?
 

·
Resident Jackass
Joined
·
1,966 Posts
Oh, that is exactly what causes the low side to read right and the high side to read wrong, the internal compressor seals are leaking. Or at least they were. If you didn't evacuate the system correctly when you put it all back together, and didn't change the orifice tube and dryer, you are screwed, especially if you got a "Factory Air" brand compressor. I have had nothing but trouble with them, and finally went and bought a new compressor for my other ride. I hope you get it figured out.
 

·
I da numba wun tunda!
Joined
·
406 Posts
did you use two wrenches to tighten all connections? you may have kinked a line if not
 

·
SoCaliS10
Joined
·
336 Posts
Discussion Starter #19
You know what... I still need to evacuate the system. Since I don't have a vacuum pump, what should I do? And if I ran it for 1 minute with out evacuating the system, would that do any damage?
 

·
I da numba wun tunda!
Joined
·
406 Posts
if you dont evacuate the system just do a refrigerant purge. Hook up you gauge to the high side and the low side. Loosen(not remove) the hose on the low side of the gauge. hook up your refrigerant bottle to the high side a let the liquid refrigerant into the system. in a few seconds you should hear the refrig hissing from the low side hose. do this for about 10-15 secs and then retighten the low side hose. then bing +/-99% of the air is out of the system...

we do this all the time in refrigeration. auto a/c shouldnt be too much different.
 
1 - 20 of 21 Posts
Top