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bikeone43 06-12-2018 09:41 PM

a/c problem
hope this is not to long my a/c has been working great around town we went to las vegas Monday on the way up a/c worked fine for about 50 miles them the air got warm for about 45 miles I went into my appt, was there for hours came out started the car and had cold air today we camr home and about 50 in the a/c started to blow warm air we got home anf my gauge reading were 5 lb low and 208 high side I lsft it alone hours later readings were 25 low 165 high I think it is a expansion valve any ideas

fdryer 06-13-2018 12:54 AM

Re: a/c problem
1 Attachment(s)
Unless you're familiar with thermal expansion valve operation and understand refrigeration fundamentals, you may be finding an answer to match your ideas of faults that may not exist. "...5 lb low and 208 high...hours later 25 low and 165 high..." is misleading info. Do you know how to correlate temperature/pressure charts from service manuals? Unless you proof read your writings, posting misinformation may mislead anyone into incorrectly giving you info that may do more damage than good. If you mean [B]2[/B]5 or [B]3[/B]5 psi low and 208 high, these values are likely correct but in comparison to what ambient temperature reference and humidity? What's outlet vent temps when these values were recorded? Refrigerant pressures along with ambient temperature, humidity and vent temps are compared to t/p charts. Below is a t/p chart for '05 Vues. The values aren't exact but close enough for reference purposes. As suggested in other posts about your ac system, its always better to have service manual info from either alldata or Mitchell.

Do you have one or two cooling fans and are they running when ac is running? Is the condenser coil blocked from free air flow? A worn out or dead fan may contribute to unusual cooling problems. One member a few years ago, in Texas, wrote about an unusual problem where ac cooling was fine at speed but almost non existent in stop and go traffic. One of two cooling fans burned out and wasn't cooling the condenser coil in low speed driving. Once replaced, ac was fine. Vehicle ac requires one or two cooling fans to force airflow thru condenser coils and radiator, running when ac is turned on. Some cooling fans have three speeds (my L300) as the ecm adjusts for ac pressures.

It's not likely for your thermal expansion valve to fail otherwise the pressure differentials would be way off. Something else is going on and a complete description is lacking for anyone to have an idea of where your problem lies.

bikeone43 06-13-2018 04:44 PM

Re: a/c problem
first of all sorry for the first post your right it made no sense it all
i was under for eye operation . now I have no sticker on car under so Saturn dealer said 1.6 lbs or 22 oz I think that was of because today a added about 8oz and brought the readings up to 34 low side 245 high side ambient 106 humidity 8% inside air at 2000 rpm 56 thanks again

fdryer 06-13-2018 05:15 PM

Re: a/c problem
No grammar police here but punctuation helps separate run on sentences. Updating your profile helps so no one has to play twenty questions with you (year, model, engine, auto/manual, etc).

From the few posts already made, is there a reason you had to vacuum your system before refilling it? Personally, I see nothing that stands out with your numbers. As outside temps rise, inside ac air temps also rise. While I don't like stating this, a temperature differential of around 40 degrees between ambient and inside vent temps is considered adequate. If you see 106F ambient with 56F inside, that's considered great.

bikeone43 06-13-2018 05:27 PM

Re: a/c problem
this all started with a leaking shrader valve from a missing low side cap. like I said I think the dealer was wrong on the refrigerant amount, but I think were ok now thanks again for your help

fdryer 06-13-2018 05:42 PM

Re: a/c problem
Hopefully, replacing a leaky valve core seals this system for trouble free cooling.

bikeone43 06-13-2018 05:48 PM

Re: a/c problem
I can only hope so thanks again

bikeone43 06-14-2018 06:35 PM

Re: a/c problem
well drove about 12 miles and cooling went from cold to hot .
ambient 112
humidity 20%
idle low 25 high 255
2000 prm low 5 high 280
vent 105
I can find no signs of a leak anywhere also high speed fan not running , fuses look good help
also when a/c is turned off readings are low side 175 high side 200

fdryer 06-14-2018 08:20 PM

Re: a/c problem
1-How many cooling fans and are any running when ac is on?

2-Is vent air flow diminished or not?

3-Did you use a uv blacklight to search for dye leaks?

Technically, when low side pressure shows 25 psi the vents should be blowing freezing air but when revving engine to 2k rpm with low side pressure of 5 psi, the evaporator should be freezing at close to 0F or the hvac box becomes a solid block of ice as moisture freezes across the coils.

Fluorescent dye is mixed with oil and circulates permanently in GM ac systems, making leak detection easier. According to your gauge pressures, a leak doesn't seem likely due to correct high pressures. A leak will result in much lower high pressures.

A few things may be considered - compressor scroll valve issues and cooling fan(s) not running. Vue compressor scroll valve issues; [url][/url]

bikeone43 06-14-2018 09:03 PM

Re: a/c problem
all the fans are working the inside blower is on high and does not change . I used a black light and found nothing , I pump it down to 4 microns , I agree with these reading it should be cold but its not , they have something about a valve in the compressor but I don.t know if this year has one thanks for the reply

fdryer 06-14-2018 10:52 PM

Re: a/c problem
The scroll control valve is on the back of Vue compressors with a diamond shaped cover. The seal leaks with oil and dye leaving a trail under the compressor case. If you click on the link, the info is there along with pictures. I'm not familiar with '09 Vue ac systems and whether or not yours uses scroll compressors. A check on rockauto would show compressors and you can examine yours. Whether your problem is related to scroll control valve failure isn't known at this time.

bikeone43 06-15-2018 12:03 AM

Re: a/c problem
I don't know myself but I will check. looking back after a long trip the pressures were 4 low 180 high and took a long time to equalize now they are both about 180 and when I turn on the air they go to 4 low and 280 high maybe there is a blockage like expansion I don't, like saying that because in the old days people had a act if blaming the valve but it looks like it could be the problem

fdryer 06-15-2018 06:04 AM

Re: a/c problem
For me personally, without in-depth information from service manuals, I cannot make any guesses where this problem lies. So far, observations about pressures are one sided with more info needed and until reference manuals are presented, its all guessing at this point. You seem to have a good grasp of refrigeration processes but hesitant to subscribe to alldata or Mitchell. Accurate info may not be accessible on the internet unless you have time and patience to scour the net for free info. Another way to find help might be asking mvac sites staffed with pros working on vehicle ac systems with public message boards like Saturnfans. And then there are repair sites like repairpal that may be helpful.

Bruce Rock 06-15-2018 05:38 PM

Re: a/c problem
[QUOTE=bikeone43;2275502] looking back after a long trip the pressures were 4 low 180 high and took a long time to equalize now they are both about 180 [/QUOTE]

180 what? If it's psi, what is a long time to you? Could the engine compartment have been at 180 degrees F?

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