Need Help diagnosing ac problem

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I have a 2003 ls v8 and it has had a slow leak in the ac system for a couple years I would just fill when summer starts and it would be done by the time summer was over. I went to recharge this year but it won't blow cold. According to the tech that charged my ac the pressures are fine. The compressor does kick on but all the lines are hot. I don't remember if it's the low side or high side but I believe one of them should get cold and I can't seem to find out why it's not. Could it be a pressure switch? The same tech said it might be the blend doors are not working and this causes the cold air to not go thru the vents but still the ac lines are not cold. I'm confused cause the compressor is defiantly turning on but just no cold air. Ant ideas on how to diagnose the problem would rather figure it out than trusting this guy thanks again lvc community
 
You really shouldn't leave a leak and just keep adding refrigerant. There are two problems with that. The first is that you are almost certainly losing compressor oil as well as refrigerant. If you are only refilling refrigerant, eventually you will lose enough oil to ruin the entire system. The second issue is that each time you add refrigerant, a little moisture gets in (and some air) as well. Your dryer may be toast at this point.

Your "tech" says the pressures are fine. What are the actual high and low side pressures with it running? There's no way for both to be correct, but the system not cool. If your suction line is not cold, then the pressures are not right and the system is not cooling.

"The same tech said it might be the blend doors are not working and this causes the cold air to not go thru the vents" - You need a new "tech." The LS has no air temperature blend doors!

A classic LS problem is for the DCCV to fail open. When this happens, you get maximum heat out of the vents, even if the compressor is running. However, this would not keep your suction line from getting cold and sweating as normal.

How are you verifying that the compressor is turning on. Are you watching the clutch engage (and disengage when you turn the climate control off)?
 
Hey joegr thank you for the fast response. Every time I recharged the last couple years The tech that did it added oil every time it was a full system recharge with oil. I didn't know about the air getting in the system which can be right is there a way of telling if the dryer is bad?when he mentioned blend doors I also was confused and that's why I kinda don't trust him. Unfortunately the tech that did it past years is no longer there. I haven't changed the dccv yet but like u said the line should be cold and it isn't. I will get pressures and get back to you on that. The lines I am touch are the lines that run along the passenger side next to the motor right out of the firewall but both are hot. And yes I definatly see the ac compressor clutch kick on and off. I am confused cause like u said if both are good it should cool. Thanks again joegr
 
QUOTE: ` yes I definatly see the ac compressor clutch kick on and off.' Énd quote.

On most cars, if the compressor is kicking on and then off,say every 10-15 seconds or less, it may be low on R-134. Of course,they can be OVERCHARGED and they will not cool very well. The expansion valve may be bad also.
Find out what your pressures are. I agree you need a different tech. don-ohio (:^)
 
One thing I forgot to Mention is for the last 3 years when I recharge the system I would use leak guard in the system. This is the one I used

http://www.amazon.com/gp/aw/d/B005D..._UL130_SR130,103_&refRID=1R3RK5759FCXEQJ111Y0

At the shop I used it on customers cars and had no problems but now the guy is saying it's not the blend doors (after I confronted him bout it) and says it might be a block. Could that be true? If so how can I flush the lines out? Any way to tell if it is blocked? I am gonna get the pressures tomorrow and get back to you guys thanks
 
Yes, leak stop is very very bad. However, if that is your problem, the pressures will be way off.
 
Just came back from another shop and they did a recharge. The system looked over charged on the low side and high side was at 150. They vacuumed put 28 ounces of refrigerant into the system and got the system to 105 on the low side and 100 on the high side but it still blow hot. One thing I did notice is the air out the center console is a little colder than the other vents but the low side line is still hot. These pressures don't sound right and also he didn't put the 7 ounces of pag oil so I don't know if that make a difference. Any ideas? Thanks guys
 
http://www.lincolnvscadillac.com/fo...ing-Hot-Air-amp-Service-Parking-Brake-Warning

I just did some research and found this thread. I have the same exact problem. But I hear if it's your dccv valve the low side should be cold but it's now. Another thing is I realized that when I drive the car the air thru the center console gets hot like the outer vents but when at idle it gets a little colder. I need some help on this please. Thanks
 
Yes, pressures are way off. The low side should always be 50 or less (35 to 40 is idea). 100 PSI is an evaporator temperature of 86 degrees, so not much cooling there. 40 PSI would be an evaporator temperature of 41 degrees.
The high side pressure should be more like 200 or more. 200 PSI would be a condenser temperature of 130 degrees, which would be reasonable if the system were moving heat.

You have two possibilities.
1. Your compressor is not pumping refrigerant (at least not much).
2. Your expansion valve is stuck open.

Certainly, failure of the scroll compressor to pump is fairly well known. Usually, it is because of a bad control valve, which can be replaced. However, when this is the problem, the AC usually works okay at higher engine RPMs.

A stuck open expansion valve is not common at all, but since there is stop leak in there, all bets are off. The expansion valve is cheap, but the whole dash has to come out to replace it.

Whatever you do (might be both, compressor and expansion valve), the receiver/dryer must be replaced, and you need to flush the heck out of the system. Be sure that whoever does this knows that it is full of the stop leak crap. It may have even clogged some of the evaporator and condenser passages. Those may need to be replaced to, as it is my understanding that they are very difficult to flush due to the small passage size.
 
Damn this sucks. Before the dash gets pulled is there a way to know if it really is the expansion valve? Also if it's the compressor is there a way to know if that's the problem? I don't mind pulling it I just want to know for sure before I do. What is the scroll
Compressor? And is there a way to flush out the system at home or it has to be done at a shop? Thanks joegr

Edit : also would a stuck open valve cause the low side to be hot like it is? This is a weird problem and I rather get it fixed asap
 
For an AC system to work, you need to have refrigerant at high pressure as a liquid and at low pressure as a gas. To do that, you need something to pump it, and you need a controlled restriction to allow the pump to build pressure. The compressor pumps refrigerant gas returning from the evaporator into the condenser. Pressure builds because of the expansion valve at the evaporator being at least partly closed. As the gas is pressurized, it wants to become a liquid. To do this, it must throw off a lot of heat. Airflow across the condenser gets rid of this heat. From the condenser, the (now liquid) refrigerant flows to the expansion valve. The expansion valve opens and closes based on the temperature of the evaporator. Pressure in the evaporator is much lower than the pressure before the expansion valve (the compressor is sucking the pressure out of the evaporator). The liquid sprays into the evaporator and boils into a gas. This takes a lot of heat, so it cools down the evaporator.

No, there's no way to be 100% sure if the problem is that there is no restriction from the expansion valve or if it is that the compressor isn't pumping.
 
Never knew that thanks for the in depth response. Would u recommend me trying this?

http://www.amazon.com/gp/aw/d/B0002...s=ac+flush&dpPl=1&dpID=41gYQoYn+vL&ref=plSrch

I don't want to pay to diagnose it unless I have to. I am tryin to fix it myself. I was gonna try to use the flush kit that i posted and replace compressor and receiver and dryer and see if that helps cause pulling the dash is a big job. Thanks
 
That is just the tool to use to get the flushing solvents in. You will need and air compressor and you will need the solvents (that's an empty can in the picture). Also, I don't see how you can really flush it without removing the expansion valve, but I guess you could try.

Once done, do you plan to try and refill yourself? If so, you will need a vacuum pump too (and not one of those that connects to an air compressor, they don't go low enough).
 
Oh that's just a can? I didn't know that but I don't plan on recharging myself I was thinking to getting it recovered at a shop then doin the work then having them recharge it back. I can get an air compressor at home and use it but what solvent should I buy?

http://www.amazon.com/gp/aw/d/B0002...s=ac+flush&dpPl=1&dpID=41gYQoYn+vL&ref=plSrch

Is that correct? I don't mind buyin both and tryin along with a New receiver and dryer and compressor. How do these flush systems work? Do I have to take every part of the ac system out in orders for it to work? I just want to try everything I can do before I pay someone to fix it thanks joegr
 
Big update just followed the low side line from the ac compressor to the firewall and the line was COOL not ICE COLD. It wasn't dripping water but it definatly was cool. Since the line is cool now could it possibly be my compressor starting to give out? Could it be the DCCV is the culprit? Since the line is cool is the expansion valve still a possibility? Could it still be a block in the system?
 
If those pressures are correct, then it is the compressor and/or the expansion valve.
The receiver/dryer always needs to be replaced when the system is opened.
Even if your DCCV is bad, those pressures say you have serious refrigerant system problems too.
 
Ok so I guess the place I brought it too had a bad gauge cause these are the real pressures I have

http://s33.postimg.org/t3wch5ci7/image.jpg

The expansion valve gets pretty cold when I put my hand on it from the engine bay, could this mean a dccv problem? I barely get any cold air out of just the middle vents but not the sides. Based on these pressures what can my problem be? Thanks for the help again
 
Okay. Those are actually pretty good, assuming the blower was on high, the engine was idling, and it wasn't too hot outside.*

I am assuming that you are getting hot air out of the side vents. Is this correct? (You are getting good airflow, correct?) A DCCV problem won't just be uncooled air, it will be very heated air coming out, including the center vents. There are a few ways to test for it. Let the engine cool completely. When you first start it tomorrow, set it to 60 and see if you get very cooled air for the first minute or so. If you do, then it turns hot as the temperature gauge starts to move off of "C", then it is probably the DCCV. You can also do the DATC self diagnostic to see if there is an electrical problem with the DCCV, the wiring, or the DATC. Getting no failure code, does not mean that the DCCV doesn't have a mechanical problem. You could also pinch off the heater cores return hose and see if the air gets cool then.




*: You may find that your refrigerant charge is a little low.
 
Those pressures was at idle blower on high and it was about 83 degrees outside. With those numbers can we rule out the expansion valve and compressor? Also with those pressures could I rule out a blockage? I will try that trick and get back to you with the results but I know for sure it hasn't been changed yet. Is the dccv a motorcrafy part only or no? Thanks joegr

Edit: I saw the person charge it to 28 ounces but didn't add oil. Could that be the case?
 
Well, that's a serious problem if all the oil was drained out, but it would be correct if the correct amount of oil was already in there. Vacuum evacuation does not remove the oil.

Those pressures rule out a single failure (just the compressor or just the expansion valve). They do not rule out a dual failure, but the odds are against that.

Yes, Motorcraft only on the DCCV. I put an aftermarket in when I needed it that day (Saturday) and couldn't get Motorcraft. It lasted about a month.
 
Hi all, been some time since I was last on this site but, issue with 2002 Lincoln LSE has brought me back. As above my AC works ,, pretty well at idle, but as rpms go above 2k, the temp at vents goes from 40ish to high 50, low 60 degrees. The compressor and drier have been replaced, (by me). Vacuum and system refill at local dependable shop, by trusted mechanic.
Does this sound like an expansion valve issue? That is the way we are leaning but.....

***** Before I pull the dash I would like to find documentation on all the crap I need to disconnect and reconnect to get to the heater core/ expansion valve. Where can I find some documentation, drawings step by step would be a REAL help. I have found paper service manuals for sale on line for $129 to way over $200.
 
This is not really what you asked for, but it is probably as close as you are going to get.
http://www.lincolnvscadillac.com/forum/showthread.php?76669-Dash-Board-Removal-Thread

Rev the engine as high as you can (just below the limiter) in park and see if the same thing happens. If it does, check and see if the AC clutch is disengaging. If it is and the pressures are correct, then it could be the evaporator temperature sensor. A few of those have failed. Also, be aware that the PCM will cut the AC off it the engine starts to overheat.
 
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