No AC Cooling

Mr Magoo · Post by **Mr Magoo** » Sun Jul 17, 2011 4:28 am

My '07 has a strange AC problem. I have no cooling. Pressure reads fine on the refrigerant, compressor clutch is engaging and running constantly, changed the in-cabin filter. Anyone have any ideas?

06pvibe · Post by **06pvibe** » Sun Jul 17, 2011 8:51 am

Replace the expansion valve.

djkeev · Post by **djkeev** » Sun Jul 17, 2011 9:39 am

Do you have a real set of gauges for high and low pressure or do you simply have the cheap gauge you can purchase with a can of R134a?? Do you know how to read and interpret the information the gauges show?These readings need to be taken while the engine is running and the AC is on.Post what gauge readings you have and we'll be able to help you understand the problem. Also post what temperature the outside air is and approximate humidity for it all factors in when figuring proper AC operation.If you have refrigerant at the proper level, the compressor is turning and the clutch is engaged, you should have cooling. I assume the blower motor is blowing as well? No blower motor, you'll think that you are not cooling.Dave

Mr Magoo · Post by **Mr Magoo** » Sun Jul 17, 2011 11:33 am

I do have the gauge that came with the 134. I do not have a set of hi and low gauges. I have experience with ac systems from my job, but not automotive systems. The pressure reading is correct for the outside air temp. It was around 40-45 with an air temp around 90 degrees. Clutch engaged, blower fine. Expansion valve is probable.

djkeev · Post by **djkeev** » Sun Jul 17, 2011 9:39 pm

A bad expansion valve can indeed present a normal low pressure reading. Sometimes, it can register as an actual vacuum as well.The high pressure side is the bigger indicator. If the low pressure is reading around normal (21-43 pounds) the high pressure will read low around 100 - 150 or so. (normal is 185 - 244)Without high gauges, you are only guessing in the dark. An overcharged system while showing a normal low pressure will have an extremely high High pressure and will not function properly.Good Luck, keep us posted,Dave

cq358 · Post by **cq358** » Tue Jul 19, 2011 12:33 pm

I did a test tonight here is the result.I just used a Fluke thermometer.Rev the engine and hold constant 2000 rpm for 20 minutes at ParkOutside Air: 77F RH 65%Vent Temperature 48.9 F with RH 58Recirc mode with lowest fan speedTX valve cycling off when vent temperature at 48.1 FishTX V cut in again (cycle on) when vent temperature at 58 FTX valve cycling interval is around 30 seconds which is normal given that the ambient temperature isn't that high.

cq358 · Post by **cq358** » Tue Jul 19, 2011 12:37 pm

I would say Vibe 's AC is under sized given that it uses the same compressor/evaporator/condenser as the Corolla maybe with a slightly higher CFM blower..Plus a black color dash board and black armrest isn't helping a lot either..Instead of a gauge, he might get a way with using a thermal couple to read the low side and high side temperature. But accuracy is not as good as using a pressure gauge.

Mr Magoo · Post by **Mr Magoo** » Fri Jul 22, 2011 12:12 am

Well, the verdict is in, condenser is leaking. $525.00 to replace. Ouch! Opinions? Is this a hard job to do myself? I am very mechanically inclined, but I realize I would need to have it pumped down and filled by someone after replacement.

06pvibe · Post by **06pvibe** » Fri Jul 22, 2011 1:10 am

Quote, originally posted by Mr Magoo Â»Well, the verdict is in, condenser is leaking. $525.00 to replace. Ouch! Opinions? Is this a hard job to do myself? I am very mechanically inclined, but I realize I would need to have it pumped down and filled by someone after replacement. An '07 w/a condensor leak? I'd be immediately suspicious if I were you. It might be a simple as an o-ring on one of the hoses going to/from the condensor. Did YOU see the leak yourself, or are you taking a "professionals'" word for it?A word of caution: I got a quote to repair my wife's former Saturn, of over $1100. I did it myself for under $300, and the car didn't need half the parts they said it did. In fact what it really needed were some new o-rings and a good charge, but I replaced the hoses and receiver/dryer anyway.That said, no they are not hard to change at all, but they are physically delicate, so care in handling is required.

djkeev · Post by **djkeev** » Fri Jul 22, 2011 1:32 am

Quote, originally posted by cq358 Â»I did a test tonight here is the result.I just used a Fluke thermometer.Rev the engine and hold constant 2000 rpm for 20 minutes at ParkOutside Air: 77F RH 65%Vent Temperature 48.9 F with RH 58Recirc mode with lowest fan speedTX valve cycling off when vent temperature at 48.1 FishTX V cut in again (cycle on) when vent temperature at 58 FTX valve cycling interval is around 30 seconds which is normal given that the ambient temperature isn't that high.You are on the money with AC preformance. At the temps you mention and the RH the center vent (where the factory manual says to take temperature readings) should be putting out around 49 / 50 degrees.Dave

djkeev · Post by **djkeev** » Fri Jul 22, 2011 1:43 am

Quote, originally posted by Mr Magoo Â»Well, the verdict is in, condenser is leaking. $525.00 to replace. Ouch! Opinions? Is this a hard job to do myself? I am very mechanically inclined, but I realize I would need to have it pumped down and filled by someone after replacement. So they charged up your AC to find the leak?Did they put a dye in the system or did they use an electronic sniffer?The sniffer is GREAT BUT....... it can do false positives in a confined area.The dye tells no lies. As long as you can see a unit or a connection the dye will pinpoint a leak with no questions.I agree, a condenser on an 07 is young. Did you ever have an accident that might have damaged it?I'd look long and hard at the connections to the unit before I yanked it out. Put some dye in and get the black light to see the leak.Have it discharged? Yeah, you should but..... how's your conscience? As a private owner your system can leak and you won't be penalized by anyone. So if a loose fitting created a leak... who's to know?I was actually told by my refrigeration guy who takes care of my commercial cooling units to screw the idea of pumping down a unit. Just let it leak out, he's got better things to do with his time and we have better things to do with our money rather than giving it to him!!Replacing the unit is straight forward if you need to.1. Remove the Cooling fan assembly2. Discharge the AC unit if needed3. Remove the Receiver / Dryer from the condenser4. Remove the condenser inlet tube and the bolt5. Remove the 2 bolts from the radiator support6. Remove the brackets from the car7. Remove the two bolts that hold the condenser8. Tip the Radiator forward, remove the condenser.Dave

06pvibe · Post by **06pvibe** » Fri Jul 22, 2011 5:13 am

My previous reply was done at work so I was in a hurry, but I too wondered if you had had a minor accident w/the car in the past that might have caused condenser damage? What worries me about this diagnoses is that you said the compressor was running. If the refrigerant leaked, or was leaking out, the low pressure switch would disable the compressor clutch.Something seems very fishy about this diagnoses.

Mr Magoo · Post by **Mr Magoo** » Fri Jul 22, 2011 11:01 am

They did do a dye check and somehow the condenser is damaged. Possibly a stone or something took a weird bounce and hit it. Going to replace it next week. Doesn't look too bad to do.

djkeev · Post by **djkeev** » Fri Jul 22, 2011 8:50 pm

Quote, originally posted by Mr Magoo Â»They did do a dye check and somehow the condenser is damaged. Possibly a stone or something took a weird bounce and hit it. Going to replace it next week. Doesn't look too bad to do.Great!!! Odd things do indeed happen on the highways. Yep, not hard to do with some basic skills and tools.Make sure they put dye in on the recharge after the repair. It lasts forever and will be a quick indicator of where any future leak may be. It costs but a few $$'s extra but well worth the investment.Dave

cq358 · Post by **cq358** » Wed Jul 27, 2011 1:46 pm

Thanks for the info!.. Mine done with the center left vent. The air from it must be travel a slightly longer path than the center Right vent.. But I doubt it would make more than 1F difference. By the way I was done with all other vents kept close. By the way, does those R134a refill kit comes with refrigerant already mix with POE oil? or oil need to add separately?

djkeev · Post by **djkeev** » Wed Jul 27, 2011 8:47 pm

Quote, originally posted by cq358 Â»Thanks for the info!.. Mine done with the center left vent. The air from it must be travel a slightly longer path than the center Right vent.. But I doubt it would make more than 1F difference. By the way I was done with all other vents kept close. By the way, does those R134a refill kit comes with refrigerant already mix with POE oil? or oil need to add separately? Do be careful, you don't want too much oil in the system. It only takes 8 oz, measure what comes out so you can replenish the same amount.It is difficult to ascertain how much leaked out, how much is caught in various components and thus, how much, if any, to add to the system.Also be careful about how much dye. You don't need a lot and the dye quantity WILL displace the R134a quantity causing operational problems. Also make sure your dye is compatible with PAG oil for they mix together.Make sure you evacuate the system and remove moisture. PAG oil mixes with moisture and loses it's ability to lubricate properly.GENERALLY speaking, not a lot of oil is lost with a refrigerant leak.IT IS ALSO EXTREMELY IMPORTANT TO PUT THE PROPER COMPRESSOR OIL IN THE SYSTEM!!!!!!!!!!!!!!!!!! DO NOT MIX OIL TYPES OR INSTALL THE WRONG OIL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Depending upon your compressor brand there are specific oils within the PAG family that are recommended.They system takes ONLY PAG oil and use only 525 viscosity mineral oil on threaded connections!!!!! Dave

jake75 · Post by **jake75** » Wed Jul 27, 2011 11:09 pm

Observations:1. With all the complexities I don't think I'll be working on my own a/c.2. Seems that the manufacturers ought to include dye in their refrigerant.

cq358 · Post by **cq358** » Wed Aug 03, 2011 12:52 pm

djkeev, Could you explain how car AC could work during winter time? Such as minus -10 C or lower than 20 F. Does the air flow path for car's AC go thru the heater core first than the evaporator? I couldn't wrap my head around that A/C could function when the cold outside air hits the evaporator without the the system cut out in low pressure. Also, doesn't the head pressure would be super low when condenser exposed to very low ambient temperature?

djkeev · Post by **djkeev** » Wed Aug 03, 2011 8:30 pm

Quote, originally posted by cq358 Â»djkeev, Could you explain how car AC could work during winter time? Such as minus -10 C or lower than 20 F. Does the air flow path for car's AC go thru the heater core first than the evaporator? I couldn't wrap my head around that A/C could function when the cold outside air hits the evaporator without the the system cut out in low pressure. Also, doesn't the head pressure would be super low when condenser exposed to very low ambient temperature?Auto air conditioning units are indeed used in the winter when your controls are set to "DEFROST" mode. Why?Because of the moisture removing properties of AC having it come on quickly removes any interior fog on the glass.You can indeed mix warm air and AC produced cold air by regulating the temperature lever on your controls, you are turning on the heater to counteract the extreme cold, energy wasting but it works!Any extended running in the winter is really outside of the design parameters of AC. AC is in it's simplest definition a conduit to carry hot air outside. While the evaporator does indeed seem to release cold into the car, it actually sucks up the interior heat and carries it outside to the condenser to be released into the atmosphere. In the winter there is no need for this activity to take place. In many home applications there are actually temperature shut off switches that prevent the compressor from running below a given temperature.How does AC work? that's a chapter or two in a book! It uses a gas that has the ability to remove heat. It really doesn't "add" cool but only removes heat. That's another Physics lesson though.Not sure if this helps answer your question. BTW, Yes, the heater core warms the evaporator unit.Dave

jake75 · Post by **jake75** » Thu Aug 04, 2011 1:13 am

Quote, originally posted by djkeev Â»Any extended running in the winter is really outside of the design parameters of AC. DaveDoes that apply to use of the "DEFROST" mode?

djkeev · Post by **djkeev** » Thu Aug 04, 2011 2:10 am

There really is no need to run AC in the winter. Many cars have it come on with the defrost setting, some mechanic say to run it 10 minutes a month to lubricate the compressor seals, some say that in cold weather the lubrication ability is reduced and running it can actually cause harm.Obviously if defrosters are designed to engage the compressor to dehumidify a car, the damage being done must be minimal or nonexistant.I'd guess there is no harm done running the defrost mode all the time, but why would you? Unless you've got a puddle of water in your car a few minutes on defrost should clear your windows right up.As in so many things, opinions cloud the ability to have clear answers. I wouldn't run the AC for extensive periods of time in cold weather simply because it isn't needed. Winter air is generally drier and is naturally cold to begin with!Dave

jake75 · Post by **jake75** » Thu Aug 04, 2011 4:03 am

Quote, originally posted by djkeev Â»I'd guess there is no harm done running the defrost mode all the time, but why would you? DaveSometimes I just forget to turn it off.

djkeev · Post by **djkeev** » Thu Aug 04, 2011 8:08 am

Quote, originally posted by jake75 Â»Sometimes I just forget to turn it off.No harm done, you are just burning dollars needlessly and without any benefit !!

cq358 · Post by **cq358** » Thu Aug 04, 2011 1:48 pm

Quote, originally posted by djkeev Â»You can indeed mix warm air and AC produced cold air by regulating the temperature lever on your controls, you are turning on the heater to counteract the extreme cold, energy wasting but it works!Any extended running in the winter is really outside of the design parameters of AC. DaveBased on your description, turning on AC during defrost mode is like running hot gas reheat to dehumidify the cabin air.In the defrost cycle, The heater core actually rejects sensible heat into the air stream and the evaporator remove the latent ( remove moisture) from the air.I have to agree with you, the oil return to the compressor would be a big problem at the suction line. Since the compressor is sitting outside at the cold environment, this circumstance makes oil more viscous and is hard for refrigerant delivering the oil back to the compressor (oil and refrigerant both have different density). To over come this situation, it require very careful line sizing. In HVAC design, the ideal air condition design is to have a air conditioning system that delivers Neutral Air, 70 F 45% RH. You can achieve that by cranking your car AC while turn the temperature up slightly to deliver this .

2002sportside · Post by **2002sportside** » Fri Aug 05, 2011 5:05 am

Quote, originally posted by djkeev Â»I'd guess there is no harm done running the defrost mode all the time, but why would you? I run in the "defrost" mode all the time because I cannot stand air blowing directly on me. So, feet and windshield is my default setting. However, I disabled the ac in defrost mode a long time ago...

cythraul · Post by **cythraul** » Fri Aug 05, 2011 7:49 am

Quote, originally posted by 2002sportside Â»I run in the "defrost" mode all the time because I cannot stand air blowing directly on me. So, feet and windshield is my default setting. However, I disabled the ac in defrost mode a long time ago...VERY interesting. How did you do that?

2002sportside · Post by **2002sportside** » Fri Aug 05, 2011 10:10 am

Quote, originally posted by cythraul Â»VERY interesting. How did you do that?Going off of memory... Remove the plastic trim around the radio, remove the radio. Down below there is a connector with a single wire in it. Unplug it. I don't remember wire color...

jake75 · Post by **jake75** » Fri Aug 05, 2011 11:48 am

So many times when I need that "defrost" to see out the front windshield - don't know why I would ever disable it.

djkeev · Post by **djkeev** » Fri Aug 05, 2011 7:38 pm

Quote, originally posted by jake75 Â»So many times when I need that "defrost" to see out the front windshield - don't know why I would ever disable it.IF I were to disable the AC on during defrost, I'd install a small push button somewhere that would allow me to run the AC if I needed to while running the defroster. I agree to just wholesale disable it would be at times very inconvenient. That being said, I currently own cars without AC and have owned a LOT of cars without AC that defrosted the windshield via warm air only. Granted it didn't always work GREAT but eventually, it did indeed work.The technology is already built into your car, why remove it and revert back to the 1960's??Dave

cythraul · Post by **cythraul** » Fri Aug 05, 2011 8:46 pm

Quote, originally posted by djkeev Â»The technology is already built into your car, why remove it and revert back to the 1960's??Well, unless I'm mistaken, pushing the A/C button or setting the dial to either defrost settings will turn the A/C on, right? Could it be that it's turned on at a lower setting? But I'd think not since a compressor is on or not...Now, I like getting some fresh air while driving but I don't like to get it thru the console vent but rather thru the defrost vent. I've been doing that ever since I started driving... I don't know, I'm like that. cyth

2002sportside · Post by **2002sportside** » Fri Aug 05, 2011 9:05 pm

Quote, originally posted by djkeev Â»IF I were to disable the AC on during defrost, I'd install a small push button somewhere that would allow me to run the AC if I needed to while running the defroster. I agree to just wholesale disable it would be at times very inconvenient. That button is already there, it's even marked "A/C" for you. Disconnecting the wire just gives YOU the option, not the car.

jake75 · Post by **jake75** » Sat Aug 06, 2011 12:35 am

Quote, originally posted by 2002sportside Â»That button is already there, it's even marked "A/C" for you. Disconnecting the wire just gives YOU the option, not the car. Duh!

cq358 · Post by **cq358** » Sat Aug 06, 2011 11:10 am

Quote, originally posted by cythraul Â»Now, I like getting some fresh air while driving but I don't like to get it thru the console vent but rather thru the defrost vent. I've been doing that ever since I started driving... I don't know, I'm like that. cythI like turning on the AC by switching on the defrost mode too! Sometime if there are 2+ people inside the vibe, the humidity level inside the car is high ( anybody with bad breath will be very oblivious , by switching into defrost helps keep the windshield cool as well as keeping cabin air feel fresh .Looks like the A/C thread got a lot of momentum..everybody interested in science!

djkeev · Post by **djkeev** » Sat Aug 06, 2011 12:07 pm

I'll have to pull out my wiring diagrams to verify, but I believe that while the AC button does indeed turn on or off the ac compressor in all heating / cooling modes, I also believe that even with that AC button off, the compressor off button is over ridden and the compressor is turned on when the Defrost setting is selected.Dave

cq358 · Post by **cq358** » Sat Aug 06, 2011 1:08 pm

This is what the Manual said:Defrost: Use the defrost mode to remove fog or frost from the outside of the windshield more quickly. The air conditioning compressor runs automatically int his setting without pressing A/C, unless the outside temperature is at or below 32F.

cq358 · Post by **cq358** » Sun Aug 07, 2011 10:24 am

I believe we are using Delphi/Delco CVC variable displacement compressorhttp://delphi.com/manufacturer...s/cvc/I have attached the comparison between Denso's and Delphi's compressor.

Attached files VariableDisplacementCompressor.pdf (184.2 KB)

No AC Cooling

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