Hoping for an A/C expert to help me.

[geosnooker2000]

I am re-posting this here because it has gone without comment in the A/C forum. Maybe it will catch the eye of someone who can help over here.

I replaced the evap core (because I inadvertently punctured it) on my '93 (R-134a) and the orifice and the drier. First I filled everything (EXCEPT the compressor) with A/C system cleaner and blew it out with compressed air as thoroughly as i could. The only thing I didn't clean actually in my hands (turning upsidedown to help drain while I was blowing clean) was the condenser, since it was still attached to the truck. I blew that clean from the driver's side to the passenger side. Who knows if I got all the old oil out?

Anyway, I reassembled the system with the new drier, evaporator, and orifice.

I hooked up to vacuum and was only able to pull down to a -21. I got there in about 5 minutes, then it wouldn't go any lower than that for over an hour.

I then let that sit for 30 minutes to find that I had no leaks.

I figured that was good enough, and started to refill. So I shut off the red and blue valves. I hooked up a can of R-134a and bled the yellow line at the gauge manifold. Then I opened the red valve and turned the can upside down. The pressure went up on the red valve to 80 or so, and the blue only to about 0 +/-.

After about 15 min. I shut the red valve off, disconnected the R-134a can, and hooked up a 3oz can of PAG100 and opened the blue valve.

Then I started the engine. I noticed the pressure go up to about 30 or 40 on the blue side, and the red side went up to about 100, maybe higher (it's hard to remember specifics as this was about 2 weeks ago). But I ran the rest of that PAG100 into it rotating it from upside down to right side up.

The compressor started cycling more and more frequently and I thought I was good, although I remember the lowside pressure readings being a little high.

I switched to the second can of R-134a and ran it in right side up. I checked the vents and they were starting to feel cold. The compressor started running full time, and I thought I was golden. I went to replace a piece of trim in the passenger floorboard, and all hell broke lose at the compressor. Sounded like bearing noise. I reached up and felt the vent and it was warm air, so I shut the engine off as soon as I could, and checked the gauge pressures. They were like 240 and 80.

I know I need a new compressor.
What else do I need, and what do I do now? I am assuming I will have to clean the entire system again, replace the drier and orifice. I want to do the oil right this time. Given my situation, how much oil and where?

And WHY couldn't I get below -20? And is that a possible cause of the compressor blow-up?

And what is that can looking thing about the size of a fist on the line going from the compressor to the condenser?

I am waiting for help here before I proceed, but i need to get this thing going!!!

Thanks in advance for any help.
George

 

[Marv]

I hooked up to vacuum and was only able to pull down to a -21. I got there in about 5 minutes, then it wouldn't go any lower than that for over an hour.
Sounds good, IF you are at an altitude of 8000 feet, IF you are at sea level it should be around 29 inches or more.
I then let that sit for 30 minutes to find that I had no leaks.
I think there is a leak.

Then I opened the red valve and turned the can upside down. The pressure went up on the red valve to 80 or so, and the blue only to about 0 +/-.
High side (red) and low side (blue) should read the same IF the compressor is not running. Sounds like the blue line was NOT connected right, or there is a major blockage between the high side and low side

I shut the engine off as soon as I could, and checked the gauge pressures. They were like 240 and 80.
With the engine OFF the pressures should be equal after a few minutes.

And WHY couldn't I get below -20?
LEAK or poor vacuum pump.

And what is that can looking thing about the size of a fist on the line going from the compressor to the condenser?
Filter.
Marv

 

[geosnooker2000]

I hooked up to vacuum and was only able to pull down to a -21. I got there in about 5 minutes, then it wouldn't go any lower than that for over an hour.
Sounds good, IF you are at an altitude of 8000 feet, IF you are at sea level it should be around 29 inches or more.
I then let that sit for 30 minutes to find that I had no leaks.
I think there is a leak.

Then I opened the red valve and turned the can upside down. The pressure went up on the red valve to 80 or so, and the blue only to about 0 +/-.
High side (red) and low side (blue) should read the same IF the compressor is not running. Sounds like the blue line was NOT connected right, or there is a major blockage between the high side and low side

I shut the engine off as soon as I could, and checked the gauge pressures. They were like 240 and 80.
With the engine OFF the pressures should be equal after a few minutes.

And WHY couldn't I get below -20?
LEAK or poor vacuum pump.

And what is that can looking thing about the size of a fist on the line going from the compressor to the condenser?
Filter.
Marv

If there was a leak, would I have not seen the -21 go toward 0, even only by a little amount in 30 minutes?

As far as the filter goes, I take it you can't change the filter without changing the whole two lines (one to the condenser, and one to the drier, connected by a manifold that bolts to the back of the compressor), correct?

Thanks Marv,
George

 

[Marv]

If there was a leak, would I have not seen the -21 go toward 0, even only by a little amount in 30 minutes?

As far as the filter goes, I take it you can't change the filter without changing the whole two lines (one to the condenser, and one to the drier, connected by a manifold that bolts to the back of the compressor), correct?

Thanks Marv,
George

Check your gage and vacuum pump by leaving both blue hoses connected to the manifold and open blue valve, should be able to pull vacuum below 28 inches. Then connect the blue hose to the low side on your AC, should be able to pull same amount of vacuum.
Sometimes a leak will not be a continus leak, but will leak above a certain pressure say 21 psi.

Filter can be replace, but getting it put into your hoses will cost about the same as a new complete hose set.

Marv

 

[alone]

the can is usually a muffler installed on compressors. (retired so things change) When I started used copper lines on cars, Last time I worked on cars rubber hoses have tiny pin holes so will not let you pull a perfit vaccum. Check screen on metering device(expansion valve) these sometimes block up-if it is, oil did not return to your compressor-it ran dry therefore froze up, A/C compressors pump oil which needs to return. Before installing new compressor must find your restriction.

 

[geosnooker2000]

the can is usually a muffler installed on compressors. (retired so things change) When I started used copper lines on cars, Last time I worked on cars rubber hoses have tiny pin holes so will not let you pull a perfit vaccum. Check screen on metering device(expansion valve) these sometimes block up-if it is, oil did not return to your compressor-it ran dry therefore froze up, A/C compressors pump oil which needs to return. Before installing new compressor must find your restriction.

Thank you alone. Great suggestion. I pulled that evaporator coil at a junk yard, and it had an orifice that had a LOT of "shrapnel" in it. I thought I cleaned it out thoroughly, but maybe I didn't?

Edit: Cleaned out the Evap coil...... Not the orifice. I threw that away.

 

[geosnooker2000]

Check your gage and vacuum pump by leaving both blue hoses connected to the manifold and open blue valve, should be able to pull vacuum below 28 inches. Then connect the blue hose to the low side on your AC, should be able to pull same amount of vacuum.


Marv

My (rented from AutoZone) gauge set only had 1 blue hose (low side), 1 yellow hose (hook to pump or cans of refrig), and 1 red hose (high side). Can you re-state what you are trying to say here, because I think you are on to something. Notice I said "rented'.

 

[Maniak]

I "think" he is trying to figure out if the pump, guages or the system is causing you to see a low vacuum.

Basically, pull vacuum on the gauge set with the lines not connected to the system and make sure you pulling 29" or so of vacuum. If not, the pump is bad, or the gauge set is bad. If you get 29" of vacuum on the gauges/hoses alone but not when you connect the hose to the system, then you have a leak in the system.

~Mark

 

[Marv]

My (rented from AutoZone) gauge set only had 1 blue hose (low side), 1 yellow hose (hook to pump or cans of refrig), and 1 red hose (high side). Can you re-state what you are trying to say here, because I think you are on to something. Notice I said "rented'.

Should have said, both ends of the one blue hose connected to the manifold.
That way one end is pluged off and the other end to a vacuum. Just to check the guages and pump.

Marv

 

[geosnooker2000]

I "think" he is trying to figure out if the pump, guages or the system is causing you to see a low vacuum.

Basically, pull vacuum on the gauge set with the lines not connected to the system and make sure you pulling 29" or so of vacuum. If not, the pump is bad, or the gauge set is bad. If you get 29" of vacuum on the gauges/hoses alone but not when you connect the hose to the system, then you have a leak in the system.

~Mark

I don't have the $280 right now to rent the gauge set and pump so I can test it. I suppose I could go up there and ask to test it on their property. I guess the whole crux of the matter is, if the pump was too weak to pull a -29" vacuum, does that change what I have to do now? As of right now, I am planning on having to:

1) Disassemble all hoses off the system
2) run cleaner into all parts (except new compressor and new drier)
3) blow clean with compressed air
4) pour 2oz into new compressor, drier, and condenser (should = +/- 8oz because there will prob. be at least 2oz I can't blow out of condenser and evaporator)
5) insert new orifice and put it all back together
6) try it again, but verify that those rental gauges and pump can handle the job

Does that sound about right?

 

[Maniak]

I'd buy a set of gauges from HFT (harbor freight tools) for $40-$50 before I'd rent a set. If you really wanted a vacuum pump you can pick them up from HFT too. The cheaper electric vacuum pupm is $99 and I know it can pull 29" vacuum.

You list of steps does sound right though.

~Mark

 

[Jason94sport]

I'm having similar issues. Replaced the compressor, condenser accumulator, o rings & orifice. I borrowed a pump & gauges from someone. I can not get the gauge below 0. I don't know if it's the gauge, pump or a bad leak.

Since I do not have the time to mess with it & I'm going to give it to a shop to put a vacuum on it, leak test it & recharge with the freeze 12 I have.