99 7.3 A/C Problem

[Cowboyup]

I have an e99 that has about 190,000. A few weeks ago it started to get hot out and tried to start using the a/c on it. The vents were not blowing cold air which in turn found that the clutch was going bad on the compressor. I decided to replace the compressor instead of just the clutch to remove any headaches later on being the original compressor that came with the truck. I bought a compressor from Napa, it’s just Napa's Cold Power, not a 4 season. Tore everything apart and replaced the receiver drier, compressor, orifice tube and flushed out the whole system using about a quart of flush. Put everything back together, including 9oz of pag oil and replaced all the o rings. Put the system under a vacuum for 5 minutes and then shut the gauges down and let it sit for 5 minutes, to check for leaks. Found no leaks so preceded vacuum the system down for about 30 minutes to makes sure the system was clean. The low side vacuumed down to 25 psi and the high side pegged all the way down. Hooked up a can of Freon and bled the line and opened up the low side to start filling. The sticker on the truck says it takes 2.6 lbs but I was only able to get it to take 12 ounces and wouldn’t take anymore. The compressor was spinning and the clutch was engaged. Checked the vent temperature and it had not moved any from ambient temperature, bout 75 degrees. With this I thought I had received a bad compressor from Napa, so I took it back to them for warranty. They had another one in stock along with all the parts that I had got with the last one receiver dryer, orifice tube, along with buying a new condenser. Got back to the shop and pulled off everything and flushed everything out that I was not replacing, evaporator, lines going from compressor to condenser, from condenser to orifice tube, and from the evaporator to the receiver dryer. Sprayer the lines out with air for extra time just to make sure no flush was still in the system. Hooked everything back up replacing all of the o rings and put new pag oil in. Vacuumed the system down for 5 minutes and found a leak on the low side switch, just a crack on the plastic, so I pulled that off and just ran a jumper wire in the plug just to see if this time it would take gas. Vacuumed the system down another 30mins just to make sure everything was clean. Hooked up a can of Freon to it and bled the line. Tried putting gas in it will the engine running and got the same result. The compressor is turning because I can see the clutch is engaged. Check all the fuses and did not find anything. I am stumped and don’t know where the next place is to look. The possibility of getting two bad compressors isn’t very reasonable. Has anybody else had this problem or have any advice what to do next? Thanks in advance

 

[zilla68]

so you put in 9 oz of pag oil pulled the compressor, and put another 9oz in?

If so I think you have way to much oil in it, pulling a vaccuum doesn't remove the oil, it clings to the sides from what i remember.

 

[Lethalthreat7.3]

Zilla68 is correct saying you have probably overfilled the oil charge but that's not causing the charging issue.the oil does two things, lubricates the compressor and insulates the interior of the refrigerant components by coating the interior surfaces and is carried throughout the system is very small amounts as the refrigerant travels.
I would look for a blockage in your hoses, gauges or Schrader valves, i have seen dozens of times where upon tightening down connections the o-ring/d-ring is worn and it is forced out of the groove blocking the port.
You need to account for the charge in the hoses as well, approx 3oz for a 48" hose.
At this point i would try the following.
Make sure no blockages as stated above.
Using nitrogen completely clear out the condenser, evaporator and lines.
Remove the accumulator and dump the oil out of it. ( there is a minimum amount of oil needed in the accumulator but you have that covered, empty it).
Make sure the orifice tube is clean with no wax or debris buildup.
Remove compressor and empty all the oil from it as well. Refer to the specs once you have it emptied to refill it with NEW OIL. PAG is very hydroscopic so don't reuse it and try to get the system sealed up as quickly as possible.( Never use an old can of PAG, it will absorb atmospheric moisture.)
Put the vacuum pump on it for a couple of hours if possible. When testing if you want at least 500 microns. With just gauges you want to shut the gauges off and let it sit for 15-20 minutes and if the needle moves AT ALL you either have a leak or moisture.
With the system in a good vacuum, hook up your refrigerant. It is critical not to allow non-condensibles/air into the system, especially with R-134a.
Make sure the line is bled between the bottle and the manifold.
Slowly send the charge to the compressor on the suction side.
You should weigh it adding the extra oz's for the hoses.
A lot of heat is produced with r-134a so put a large fan in front of the condenser on high to simulate 35mph running down the road. This airflow is needed to disappate the condensing heat.
Should work for you.

 

[zilla68]

yes, I was just saying if he overfilled the oil he has another issue to figure out.

If you use compressed air, your getting some moisture in your system, nitrogen is the preferred method of clearing the lines.

On a side note, and I wouldn't have believed it if I hadn't seen it, but my buddy just sold a 72 vette that the a/c wasn't working in. He pulled the compressor, did not pull a vacuum, shot in 3 cans of Freon and it was ice cold. I swore up and down it would never work, but he was selling it quick and the guy wouldn't buy without the a/c working, he drove it about a week off and on and it was still cold.
I would have never thought it was possible.

 

[Cowboyup]

so you put in 9 oz of pag oil pulled the compressor, and put another 9oz in?

If so I think you have way to much oil in it, pulling a vaccuum doesn't remove the oil, it clings to the sides from what i remember.

No, each time I pulled the compressor, now a total of 2 times, I have completely flushed the system using flush fluid and then ran compressed air through each component for 10 mins to make sure I could get as much flush fluid and oil out as possible. After this I put 9oz of pag oil in the compressor, what I was told was the factory spec.

 

[Cowboyup]

Zilla68 is correct saying you have probably overfilled the oil charge but that's not causing the charging issue.the oil does two things, lubricates the compressor and insulates the interior of the refrigerant components by coating the interior surfaces and is carried throughout the system is very small amounts as the refrigerant travels.
I would look for a blockage in your hoses, gauges or Schrader valves, i have seen dozens of times where upon tightening down connections the o-ring/d-ring is worn and it is forced out of the groove blocking the port.
You need to account for the charge in the hoses as well, approx 3oz for a 48" hose.
At this point i would try the following.
Make sure no blockages as stated above.
Using nitrogen completely clear out the condenser, evaporator and lines.
Remove the accumulator and dump the oil out of it. ( there is a minimum amount of oil needed in the accumulator but you have that covered, empty it).
Make sure the orifice tube is clean with no wax or debris buildup.
Remove compressor and empty all the oil from it as well. Refer to the specs once you have it emptied to refill it with NEW OIL. PAG is very hydroscopic so don't reuse it and try to get the system sealed up as quickly as possible.( Never use an old can of PAG, it will absorb atmospheric moisture.)
Put the vacuum pump on it for a couple of hours if possible. When testing if you want at least 500 microns. With just gauges you want to shut the gauges off and let it sit for 15-20 minutes and if the needle moves AT ALL you either have a leak or moisture.
With the system in a good vacuum, hook up your refrigerant. It is critical not to allow non-condensibles/air into the system, especially with R-134a.
Make sure the line is bled between the bottle and the manifold.
Slowly send the charge to the compressor on the suction side.
You should weigh it adding the extra oz's for the hoses.
A lot of heat is produced with r-134a so put a large fan in front of the condenser on high to simulate 35mph running down the road. This airflow is needed to disappate the condensing heat.
Should work for you.

That was my first thought that I had a blockage, but with a new parts other than a couple hoses and the evaporator, where could the blockage be?

 

[fordfreak4life]

did u flush it after installing the new receiver dryer? btw you should never flush through anything but hoses and the evap n condensor

Sent while spinning 18 wheels

 

[Cowboyup]

did u flush it after installing the new receiver dryer? btw you should never flush through anything but hoses and the evap n condensor

Sent while spinning 18 wheels

I flush it when everything is unhooked, I wouldn't flush the condenser on a newer system like this because the passage ways are so small it is hard to clean them all out.

 

[Lethalthreat7.3]

Running compressed air in. R-134a/PAG oil system for twenty minutes is one of the worse things you can do for the system.
Try running the compressor discharge air into a rag for that time period and see just how much moisture is there. Moisture and pag creates hydrofluoric acid and this literally dissolves the internal aluminum components. I have seen compressors that look like a torch has been put to the aluminum and everyone knows what happens with that.
I still believe you have some type of blockage.
If you used compressed air i would be willing to bet it is the accumulator. They do not take to flushing because of the desiccant and adding moisture from compressed air multiples the problem. Then there's the orifice tube that is sure to be clogged.
If you know for sure the hoses are restricted( try changing the suction with the discharge hose just to see if it will feed.
Also, what are your exact pressures? Outside air? Cab air? Discharge air?
With some more info we may be able to narrow down exactly what is going on.
IMO the compressed air/moisture may be the culprit causing the refrigerant to "stack" in the accumulator but without some actual pressures it is all just theory.

 

[Cowboyup]

Running compressed air in. R-134a/PAG oil system for twenty minutes is one of the worse things you can do for the system.
Try running the compressor discharge air into a rag for that time period and see just how much moisture is there. Moisture and pag creates hydrofluoric acid and this literally dissolves the internal aluminum components. I have seen compressors that look like a torch has been put to the aluminum and everyone knows what happens with that.
I still believe you have some type of blockage.
If you used compressed air i would be willing to bet it is the accumulator. They do not take to flushing because of the desiccant and adding moisture from compressed air multiples the problem. Then there's the orifice tube that is sure to be clogged.
If you know for sure the hoses are restricted( try changing the suction with the discharge hose just to see if it will feed.
Also, what are your exact pressures? Outside air? Cab air? Discharge air?
With some more info we may be able to narrow down exactly what is going on.
IMO the compressed air/moisture may be the culprit causing the refrigerant to "stack" in the accumulator but without some actual pressures it is all just theory.

I agree with you on the compressed air but I am out in a very remote location of North Dakota and don't have any access to nitrogen. I checked the air for moisture and it was dry in a rag. My first guess would have been the accumulator, or receiver dryer, but both that I have put in are brand new. The orifice tube is also brand new both times and the first new one that I replaced looked practically as it did coming out of the box. Exact pressures were 75 on the low side, 75 on the high side. The temperature outside was 78, and the air blowing out the vents was 78. Thanks for the help so far, I've done many systems but this one has me stumped.

 

[Lethalthreat7.3]

Equal pressures indicates that the orifice is not functioning properly. Make sure the o-rings are good and that you have it fully seated into the tube in the proper direction. If it is installed upside down it will not meter the refrigerant. When the metering device is working properly you will feel the temperature change and this is what causes the condensation.

 

[Cowboyup]

Equal pressures indicates that the orifice is not functioning properly. Make sure the o-rings are good and that you have it fully seated into the tube in the proper direction. If it is installed upside down it will not meter the refrigerant. When the metering device is working properly you will feel the temperature change and this is what causes the condensation.

Sorry about the late response, had a lot of work come up and then had to drive back down here to Colorado. I replaced all the orings, 3 of them, when I was in there, and I would think if there was a bad one I would have found it leaking when I put a vacuum on the system. As for the orifice tube, I made sure that it was fully seated and the arrow was in the direction of flow, from the condenser to the evaporator.

 

[Cowboyup]

Well to add to the list of problems I am having with this system I went out today to just check the pressures and see if anything had changed, the a/c was not on the entire time I drove down from North Dakota to Colorado. Fired the truck up and turned the a/c on, looked under the hood and the a/c clutch wasn't engaged. Checked all the fuses and everything was fine, checked voltage at the clutch and had 11.97 volts. With the key on I can press the clutch with my hand and it will engage, and will stay engaged when I start the engine. With the engine running, a/c clutch engaged I hooked the gauges up and the pressures were 80psi on the high side and 86 on the low side along with outside temperature being 80 degrees. With finding these results, there seems to be a problem with the clutch, but it is brand new along with the compressor.

 

[zilla68]

where are you buying the compressors?
and please don't say autozone

 

[Cowboyup]

Napa, its just their "cold power". I made sure it was not a 4 seasons

 

[zilla68]

with your high and low side that close somethings off, I'll get back with you after I think on it a little more.

 

[Lethalthreat7.3]

Just gave you a call.
The issue with the clutch not pulling in is the "air gap". Everyone keeps talking about pulling the washer or shim. These are different thickness so that the gap can be adjusted between the clutch and coil. Different coils have different specs(any info or extra shims should have been with the new clutch and look like little washers)
The pressures being equal indicate that the metering device is not functioning. Since you use an orifice tube either it is upside down, not seated fully, is damaged or an o-ring is bad.
If i remember way back in say '88 or '89,(ok maybe i'm getting old) I got some orifice tubes that had the damn arrow going the WRONG direction. (This thread just reminded my aging butt!)
I went through the same b.s as you have Cowboyup(sounds like you've done a really good job from you description).
The air gap is an easy fix. The orifice, well you know the drill. Just pull out the gas, flip the orifice over and make sure it seats. Vacuum and I bet it charges.

 

[zilla68]

any updates?

 

[Diezel Dawg]

Check your wiring on low and high pressure sides. Wiggle the wiring and see if it engages. If so, replace the pigtail, that's exactly what was wrong with mine

Sent from my PG86100 using Tapatalk 2

 

[Lethalthreat7.3]

He got it fixed last night. He had a restriction in his manifold gauge set preventing him from properly being able to vacuum, charge or properly read pressures.
Been working over the phone with him. He was doing a great job but the o-ring/d-ring in one of the hoses was the culprit.