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HVAC Gurus, I decided to replace my AC system since I was tired of sweating all the time...Long story short I replaced the compressor, AC lines, accumulator, and orifice tube. The old AC line rubbed against the control arm and created a hole, I used the harbor freight vacuum pump and gauge set to drain it, although there was nothing to drain because of the hole. The gauge did pull a vacuum down to -30 while draining, now that I have everything put back together it is not pulling a vacuum? What gives? I made sure all connections are tight, all new O-rings, even added Teflon tape for shiggles. Oil added to both compressor and accumulator.

The pump is running, and there is a vapor cloud coming from the pump, indicating moisture I believe, but it has been running for last 2 hours and still reading 0 degrees on low side. I wouldn't think the gauge is defective since it worked yesterday but then again it is a HF tool. Could there be that much moisture?

Thanks for any help!
 

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Discussion Starter #2
I pulled the compressor and lines off, checked everything and re-tightened everything, still no dice. I'm at a loss, I really can see anything that I've missed.
 

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HVAC Gurus, I decided to replace my AC system since I was tired of sweating all the time
Okay, when I first read the subject of the message a day or two ago, I assumed it was referring to an engine problem, and didn't look at the section where it was posted. I've got a lot of A/C experience and hope I can help, but first I'm going to ask you a lot of detailed questions which may seem over reaching, but I don't want to assume anything.

Long story short I replaced the compressor, AC lines, accumulator, and orifice tube.
1. Were these all new components?

The old AC line rubbed against the control arm and created a hole,
Okay been there done that originally with my 9C1. Now that you've installed the new hose assembly, do yourself a favor and get some heater hose and wrap it around each hose in the control arm area, and secure with nylon wire ties.

You can also 'massage/form' the hoses gently a bit away from the engine area itself as well. I had to do this to get greater clearance away from the Clear Image headers.

I know you've got your system together already, but as a reference I did this the last time I worked on the A/C system, by putting the bulkhead of the manifold assembly in a vise, and bending the tubing slightly. Then installing on the stud off the back of the compressor. I did this on and off for probably an hour before I had a good amount of clearance, but could still access the flange head nut holding it to the compressor well.

If you want to see some pix I can take some this morning once we get daylight when I get to work. I used to have some, but since Imageshack took away free images I'd have to search my SD Card for them.

I used the harbor freight vacuum pump and gauge set to drain it, although there was nothing to drain because of the hole. The gauge did pull a vacuum down to -30 while draining, now that I have everything put back together it is not pulling a vacuum? What gives? I made sure all connections are tight, all new O-rings, even added Teflon tape for shiggles
2. Did you install/replace -ALL- the O-Rings @ Each tubing connection, or only the connections you broke?
2A. Did you lubricate them with a touch of the PAG oil?
3. Did you install new sealing washers at the back of the compressor to bulkhead connection?
4. I can understand why you did the teflon tape, but it's absolutely doing nothing since the tubing connections seal by the flares at each end.


Oil added to both compressor and accumulator.
5. Not that it matters in the terms of pulling a vacuum, but since were covering all bases here, how much oil was added to each?
6. Did you drain oil from the compressor prior to adding?
*I know you mentioned you replaced it* but I have seen compressors shipped dry when they are supposed to ship with oil installed. I drain the oil from the compressor into a measuring cup to verify.
7. Which post of the compressor did you add the oil to?
*It should have been added to the 'S' (Suction) side, and then rotated the clutch to pull the oil thru the compressor.
8. Did you flush the condenser?
9. Did you flush the evaporator core?
10. Did you flush the lines?

It shouldn't matter whatsoever, but it's possible you could have too much oil in the system, depending how much you added if you didn't flush the components I asked about in questions 5-10. Too much oil will not allow the system to work properly, and it won't get as cold as it should, so it could be a hinderance to have too much.

The pump is running, and there is a vapor cloud coming from the pump, indicating moisture I believe, but it has been running for last 2 hours and still reading 0 degrees on low side. I wouldn't think the gauge is defective since it worked yesterday but then again it is a HF tool. Could there be that much moisture?
10. Okay. How is the vacuum pump connected? To where?

Are you connecting the pump directly to the accumulator/receiver-dryer?
OR
Are you using a set of gauges connected to the high & low sides, and then the compressor vacuum line connected to the center port of the gauges where you'd connect the can of freon?
-If the latter, it the low side valve open?

I pulled the compressor and lines off, checked everything and re-tightened everything, still no dice. I'm at a loss, I really can see anything that I've missed.
My questions may seem a little much, but to do some internet laptop diagnostics I don't want to assume anything, and need to cover all the steps I can think of to help you.

As a note, I had a friend who did a bunch of work, and then couldn't pull a vacuum either, and it came down to the expansion valve being stuck open. I'd have to go look at my service manual, but I don't recall if there is an expansion valve up by the evaporator core in the cabin.

Feel free to reply here or PM me.

LASTLY, are you working on a '96 as listed in your SIG, or what year and model is it?
 

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the process you did is not proper. ac hose on the control arm worn and leaks . no need to put vacuum pump on it ..

replace compressor and the filter drier .. use the ac flush to wash out the condenser and evap.. use air pressure to blow out all the cleaning product ..then you install all the components back with new O rings and put some ac oil on them... you do not use any tape LOL... when put back the pump is not creating vacuum well then you add some 134 and find out where it leaks.. when installing a new compressor you must use the proper oil and the leak dye .. this will reveal leaks easy..

on the ac compressor mounting the front of the compressor is bolted on first.. then in the rear is an ear that holds it to the frame.. that metal support must be loose at the frame then tighten the support metal on compressor then tighten the frame end ... this is important because it can stress out the compressor body causing the seals to leak ,, that was the hardest part of the job for me very tight area .. documented info about the rear support on compressor stress due to heat/cold ...

my compressor stated pag150 oil but ??? your compressor it can be different.. my 96 OEM did come with r134 and Pag 150 ..
 

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Discussion Starter #5
1. Were these all new components?
A: Yes they are


2. Did you install/replace -ALL- the O-Rings @ Each tubing connection, or only the connections you broke?
2A. Did you lubricate them with a touch of the PAG oil?
A: The new hoses came with new o-rings so I left those on there,

3. Did you install new sealing washers at the back of the compressor to bulkhead connection?
A: Yes and lubed with pag oil

4. I can understand why you did the teflon tape, but it's absolutely doing nothing since the tubing connections seal by the flares at each end.
A: makes sense, and I ended up taking the tape off

5. Not that it matters in the terms of pulling a vacuum, but since were covering all bases here, how much oil was added to each?
A: 4 oz to compressor (no instructions came with it so I added oil to both S & D marked holes and also the middle bolt in the compressor had a hole so I added some oil to that). I attached the new lines and some oil seeped into those, since snaking the lines through the engine bay was 'fun'. Added 3oz to accumulator, again adding it through each hole. I'm hoping thats not my issue but who knows

6. Did you drain oil from the compressor prior to adding?
*I know you mentioned you replaced it* but I have seen compressors shipped dry when they are supposed to ship with oil installed. I drain the oil from the compressor into a measuring cup to verify.
A: Yes

7. Which post of the compressor did you add the oil to?
*It should have been added to the 'S' (Suction) side, and then rotated the clutch to pull the oil thru the compressor.
A: see answer above

8. Did you flush the condenser?
A: yes

9. Did you flush the evaporator core?
A: yes

10. Did you flush the lines?
A: no

It shouldn't matter whatsoever, but it's possible you could have too much oil in the system, depending how much you added if you didn't flush the components I asked about in questions 5-10. Too much oil will not allow the system to work properly, and it won't get as cold as it should, so it could be a hinderance to have too much.

10. Okay. How is the vacuum pump connected? To where?
A: Red line to High side, Blue to low side/accumulator, yellow line to pump

Are you connecting the pump directly to the accumulator/receiver-dryer?
OR
Are you using a set of gauges connected to the high & low sides, and then the compressor vacuum line connected to the center port of the gauges where you'd connect the can of freon?
-If the latter, it the low side valve open?




My questions may seem a little much, but to do some internet laptop diagnostics I don't want to assume anything, and need to cover all the steps I can think of to help you.

As a note, I had a friend who did a bunch of work, and then couldn't pull a vacuum either, and it came down to the expansion valve being stuck open. I'd have to go look at my service manual, but I don't recall if there is an expansion valve up by the evaporator core in the cabin.

Feel free to reply here or PM me.

LASTLY, are you working on a '96 as listed in your SIG, or what year and model is it? Yes it is my 96
 

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these vehicles have NO expansion valves !!! that is why it has the IN LINE orifice..

you must take it all apart and remove all that teflon tape ! as was mentioned oil on O rings..

I forgot to say YA I have AC license .. also I did work on ac units as big as the impala the Whole car ...those huge units do have expansion valves .... reason they had that valve is the massive flow of refrigerant ... the units had 2 expansion valves ...

shoot some gas in the system and see where it leaks .. R134 or perhaps you have some nitrogen gas ....if you do use the nitrogen keep in at 100psi ...
 

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Discussion Starter #7
I pulled everything a third time, flushed it all with 2 containers worth of AC flush, removed all Teflon tape, drained all oil and re-added it back to compressor and accumulator, and put it all back together...still reading 0 on the gauge :(

So I'm taking the gauge set back to HF to exchange it and see if that is my problem. I didn't want to add R134 yet till I get a vacuum but that will be my next move. I'll keep you all posted.
 

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[SNIP]

So I'm taking the gauge set back to HF to exchange it and see if that is my problem. I didn't want to add R134 yet till I get a vacuum but that will be my next move. I'll keep you all posted.
This was going to be my final suggestion, as it really doesn't make sense as long as the vacuum pump is operating okay.

I suppose you could also try connecting the gauges to a working vehicle prior to attaching to your car to ensure they work properly.

Keep us in the loop....
 

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Discussion Starter #9
Good news...it was the manifold gauge set being defective. I exchanged it at Harbor Freight and the new one pulled a vacuum. Bad news is I think there is a small leak somewhere because after I pulled a vacuum for 3 hours, I left it sit for 5 hours and it lost 2 degrees. I put in some UV dye with R134a so we'll see where it is at. I did bend the lines slightly to clear the TriY headers but they are still too close for me. I also put some old radiator hose cover the area with the control arm, we'll see how that hold up...

Thanks for everyones help so far, really appreciate it
 
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