Hi All,

I searched all the forums on ac issues, and couldn't find a specific answer. Was hoping to get some insight into this issue I am having. I purchased a 2008 LR3 with a broken AC, took it a shop and they said the compressor was bad because it was only getting 1V and it was acting like a fuse. They were charging an arm and a leg so I thought I could replace it myself. I called another mechanic, and he said that it was the pressure sensor. I bought the parts, but couldn't find time to replace it, so I took it to a different shop who installed both, evacuated and refilled the system 3 times, and still blowing warm air.

I am running out of options, even the shop was scratching their head. I don't want to get rid of this car that I just bought and spent a ton of money on, but I do not want to throw more money into it. Can someone please help?? Any insight is greatly appreciated.

Thanks,

 

Could be a blend door stuck on heat. Do you get warm on both sides? There seems to be two blend doors because of the dual climate controls. It would be odd to have both fail in the same way.

 

It's ambient temperature on cold, and hot on hot. There is a temp change when you switch it from cold to hot. Same thing happens on the rear system. So I assume it's got to be the main ac components. What are your thoughts?

Any help appreciated.

 

You need to get a mechanic (or yourself if so equippied) to put a set of gauges on the system and see what the pressures are doing. I'd be surprised if one of the mechanics along the way hasn't done this, but if you can report back those measurements it may help determine what's wrong. Often times when a compressor dies if can introduce material into the system that will clog the expansion valve. If your compressor actually did fail, seeing 1v at the compressor could simply mean that the system isn't calling for it due to high pressure. Replacing a pressure switch won't correct the high pressure problem if the system isn't circulating due to a clog.

 

^ With all that said, and I agree, the AC shops should be observing the pressure when filling not to mention measuring what is going in. And if they are getting proper pressures when running the engine the system should be working fine.

Quick test when you can, operate the system full cold and feel the high and low pressure lines in the engine bay. One should be colder than the other. If that is the case then it has to be an HVAC system issue with all teh various blend doors, sensors, etc. If after a while they are still warm then, in theory, it could be a lot more things but then I would not understand how they are properly filling it.

Need some more diagnostics maybe. Always start simple, go from there.

 

Thanks, I will have the shop check the pressure. They use those automatic Refrigerant machines. I don't recall if the engine was running when they were filling. I will report back on the pressures. The first shop said the compressor failed, but when replaced, nothing changed. If it's a clog where can it most likely happen? BTW the drier was replaced as well. Would it be in the Expansion valve? Would you recommend those ac flushes?

 

As said before, the various mechanics should have tested all things but a leak test wouldnt go amiss here. just because the machine says it put 2 lbs or whatever in, doesnt mean that your system has x lbs in it. Agreed with test the lines for temp change. My thinking is somebody lost a seal in the part swaps.

 

Hi guys,

The pressure gauges show 80 on the low side, and 95 on the high side. I'm not sure if that's a good or bad thing. The Temps on the lines are the same temp just slightly cold but not the way it should be. I didn't have anything to check the temp just by feel. No moisture on either lines. No leaks as the mechanic can see. We put UV dye, and don't see any visible leaks.

 

Thats not right, by a long shot if one is expecting some nice cold air. The pressures should be largely different. You low is too high, your high is too low. Its like the compressor was not really running. Its always operating though, at least 5%? (someone can correct that). So there will always be a pressure differential. But at about 75 degrees your low should be about 40 and your high should be about 160 when its full operating.

Since I am less familiar with these clutchless/constant-on compressors someone will have to chime in if those value are normally for one operating at minimum. If its normal, the question is why is it not engaging fully. Fuse? Someone forgot a connector? Expansion valve stuck wide-open?

 

I see. I wonder why. Fuses look good in the engine bay unless there is something somewhere else that I am missing. I wanted to check the electrical connection at the compressor, but I'd have to have them put it back on the lift to take the bottom skid plates off or the driver side wheel well cover. I guess the shop just bought the machine and really isn't too well versed on AC. I'll have them check tomorrow.

Thanks,