Automotive Air Conditioning Information Forum (Archives)

Briandl79 on Thu May 26, 2011 7:12 PM

Year: 2006
Make: Jeep
Model: Commander
Engine Size: 5.7
Refrigerant Type: R134A
Ambient Temp: NA
Pressure Low: NA
Pressure High: NA
Country of Origin: United States

Without giving you my life story right this minute, I've had some trouble with my A/C not cooling well enough and I had two questions regarding that.

First, can a compressor be going bad to the point that it still cools but does not cool very well? Could it do this for a year or more, or does say a compressor just crap out, or it if does limp around does it do it for that long?

Also, would a bad receiver/dryer cause a problem like this?

TRB on Thu May 26, 2011 10:15 PM

Can your heart pump even though it is old and weak?

-------------------------

Briandl79 on Thu May 26, 2011 10:19 PM

Well mine isn't old and weak but I believe the answer is yes.

I also figured by reading here that not replacing the receiver dryer could be a problem as well, but maybe only if the compressor was going out any way. If that makes any sense.

TRB on Thu May 26, 2011 10:24 PM

You're not proving enough info to help determine what might be the problem. Not cooling? Why is it not cooling. Do you have a proper refrigerant level? What are the pressures? What has been done to the a/c system (repair) that might be causing the problem. Feed us some info and we might be able to assist.

-------------------------

Briandl79 on Fri May 27, 2011 4:32 PM

Well I was just wondering in general. Let's see if I can remember the rest:

Cools okay when it's below 80, but when it gets into the 90's you can tell it's not cool enough. Today for example it was about 94 outside and on the highway with recirc on it was blowing between 50 and 54. Once you stop it jumps up to as high as about 66. The factory service manual says it shouldn't go higher than 56 or so, and I think that's worst case scenario, normally it's probably much lower than that.

I was diagnosing this about a year ago and found I'd had a leaking evaporator core. I drained the old one and put the same amount of oil in the new one plus a bit because I knew I didn't get it all out, I also replaced the txv and filled it to the correct amount of refrigerant, I believe off hand it calls for 32oz or so.

I did not replace the dryer when I did that, although I know I should have. Other than that I can say the low side from the txv isn't very cold.

I don't have any gauges right now so I can't give pressures. Well I do have gauges but only the low side works, the high side broke and needs to be fixed/replaced.

TRB on Fri May 27, 2011 4:36 PM

Did you just add refrigerant after replacing TXV or did you pull a vacuum first?

-------------------------

Briandl79 on Fri May 27, 2011 4:53 PM

I pulled a vacuum, not only to check for leaks but also as part of refilling the system.

Edited: Fri May 27, 2011 at 4:55 PM by Briandl79

Briandl79 on Wed June 01, 2011 10:27 PM

Got some new gauges because my old ones were broken. Here's what it read, I'll try again when it's nice and hot:

Ambient 85
40 Low
270 HIGH
56 Vent Temp


Service manual says:
Low 20-40 PSI
High 250-275 PSI
Max Vent Temp 51

Edited: Sat June 04, 2011 at 2:52 AM by Briandl79

Briandl79 on Thu June 02, 2011 3:50 PM

Checked again:

Ambient 93
37 LOW
230 HIGH
56 Vent Temp

Briandl79 on Fri June 03, 2011 8:14 PM

So I finally took it to a shop and the guy basically told me that my system was showing early signs of compressor failure. He said the low side was reading a bit high, and that it wasn't as stable as it should be. The low side was reading somewhere around 40-45 PSI.

I never knew you could tell the compressor was on its way out by the low side, I always thought the high side was where you checked compressor performance, but there's really nothing else that really could be wrong but the compressor.

I initially took it in to see if they could find out if it had too much oil, but all they wound up doing was getting two ounces out and replacing it with two ounces of new oil so whatever it had before it's still the same.

Briandl79 on Fri June 03, 2011 11:13 PM

Oh by the way, any thoughts or confirmation from the pros?

JJM on Sat June 04, 2011 12:30 AM

Based on the readings you provided, there's nothing wrong with the compressor. I see no indication of compressor failure from those readings.

Was there any debris in the TXV when you removed it? If there wasn't, the likelihood the compressor is bad or going bad is even less.

Always replace the dryer when you open the system. Not doing so is kind of like replacing the oil pump on your engine, but not changing the oil filter - just doesn't make sense.

Have you clamped off the heater hoses for at least 15 minutes to confirm there's no heater intrusion?

Joe

Briandl79 on Sat June 04, 2011 1:44 AM

No the TXV was fine. The only thing I noticed while experimenting with it is that the new one seemed to open up and allow water through it if the water was ice cold, but the old one did not. I made sure to dry it out before I installed it and of course pulled a vacuum.

The drier has been replaced as well just the other day.

I have not clamped off the heater hoses, however from a cold start the A/C doesn't blow as cold as it should, well before the heater core has had a chance to warm up. Also I don't think I mentioned in this thread but I have rear ac and the rear ac puts out about the same kind of temps as the front, if the blend doors were allowing the heat from the heater core to mix in with the cold air from the evaporator core, it's unlikely that problem would exist in the rear as well.

What else would cause the low side to be a tad bit high and to fluctuate somewhat? There's no air in the system and I'm leaning towards there not being too much oil because it takes a full charge.

Edited: Sat June 04, 2011 at 2:57 AM by Briandl79

Briandl79 on Sun June 05, 2011 5:38 PM

Bump for any other thoughts. I spent most of last summer trying to fix this and never did, I don't want to spend all summer doing this again, but I can't necessarily afford to just take this somewhere and have them charge me out the nose to fix this. Especially since I already took it somewhere and it's possible they didn't diagnose it correctly, and wanted at least almost 800.00 to fix it.

Briandl79 on Mon June 06, 2011 5:20 PM

Bump

Dougflas on Mon June 06, 2011 5:39 PM

need more info. Is the vehicle in thwe sun or shade while testing? DId you try to mist the condenser with a wate hose and see what the readings were? Is the correct amount of refrigerant in the system? You have a lot of glass on this vehicle that will allow the sun to heat the interior.

Briandl79 on Mon June 06, 2011 5:53 PM

It's in the shade, but it's still pretty hot. I did try to mist the condenser, it makes virtually no difference. As far as I recall the pressure's drop slightly but the temps stay virtually the same. Yes the correct amount of refrigerant is in the system as done by myself, and as measured at a shop. Yeah it does have a ton of glass, and I don't think it's that far off but 5-10 degrees makes all the difference.

Briandl79 on Wed June 08, 2011 2:53 AM

Test drove two similar vehicles, one the same year and one two years newer, apparently that's just about as well as it should cool. I was used to my previous Jeep that cooled noticeably better. Case closed.