NEED HELP A/C Blowing hot air most of the time!

Hobbyist4Life

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Sep 5, 2016
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Hello!

I've been having a issue with my blazer's A/C since I got it about 2 years ago. It simply doesn't cool most of the time, especially in summer.

This summer I went ahead to start fixing the problem.

What I've done to begin with:
- Replaced compressor with brand new ACDelco
- Replaced accumulator with brand new ACDelco
- Replaced orifice tube with brand new ACDelco

Got it filled up with gas at the shop, and it still doesn't cool as it should.

So I decided to remove the evaporator and check it, and after getting it out I found out that it was clogged from the old compressor so I gave it to the shop and they used some petrol and compressed air to get it to open, and I made them clean the condenser at the same time just in case.

After closing the dash and everything up and filling it with gas, I found out that it still doesn't cool.

Current situation is as follows, at night and early in the morning, the air is kind of warm and suddenly it starts blowing more air and start blowing ice cold air.

But any other time between early in the morning and night the A/C blows hot air, unless it decides to increase blower speed and starts blowing ice cold air.

The compressor DOES cycle on/off, goes off for ~8 seconds and then on for 1~2 seconds (not always). Even if it doesn't cycle it still blows hot air, until it decides otherwise.

I've tried to command the compressor to stay on using the Autel DS708 but again, doesn't cool.

Just to be sure, I have to fill it with 860g of gas and 220ml of oil, right? What would happen if oil was less?

Any help is appreciated.

Regards,
Hobbyist4Life
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Just to confirm that it's a TrailBlazer you have and not a Blazer (the older smaller type) and short wheel base (5 passenger).

The amount of refrigerant sounds about right (I got 0.85Kg). The oil depends on which components are replaced or drained of oil.
Accumulator: 60ml
Compressor: 60ml
Condenser: 30ml
Evaporator: 90ml
total oil capacity: 240ml

You may have put too much oil by possibly 30ml since the condenser is the only component that wasn't replaced. I don't think it's a problem.

When it's running, is the accumulator cold, even when blowing hot air? If so, I believe that a blend door actuator may be defective.

Or if it's first cold then warms up while idling, then the fan clutch is suspect. Test it. Also check the relay.
How to test the electro-viscous fan clutch
 

mrrsm

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Oct 22, 2015
7,642
Tampa Bay Area
Please forgive many of these questions if they seem too obvious to ask… but diagnosing your present HVAC problems can be difficult without knowing the answers to the following issues:

(1) After installing all of your OEM AC-Delco components and adding PAG Oil… prior to introducing the proper weight of R-134A Refrigerant… Did you use a Two Stage Scroll Vacuum Pump to evacuate atmospheric air, moisture and non-condensible gases? (...about $100 @ Harbour Freight)

(2) If the answer to the above is YES… Did you attach an Auto HVAC Manifold Gauge (.. also available at HF) prior to pumping the system down and confirm that the system was capable of holding a vacuum with minimal loss of vacuum over a 30 Minute Period?

If the answers are all NO...Then these other symptoms can be explained as follows and unfortunately... must begin with replacing the PAG Oil and the Accumulator and then flushing the system... without flushing the New Compressor...BEFORE moving on as they will already be contaminated with too much moisture and MUST GO:

Even with all Brand New High Quality OEM Parts, Components, Refrigerant and Lubricants… without vacuuming out all of the Moist Air and Non-Condensible Gases present in the atmosphere inside the Truck’s entire AC System… the AC will NEVER cool. The reason for this in a word is this: WATER. Even microscopic amounts of water hidden or lodged anywhere in the system will eventually FREEZE and plug up the points inside the system where the compressed Liquid Refrigerant is supposed to undergo a “Phase Change” from being a solid stream of Warm Liquid Refrigerant… and FLASH over into a GAS.

This process happens on the other side of the Orifice-Filter Tube at a proscribed rate so that the liquid phase changes inside the Evaporator Coil in just the right way… under the dashboard of your truck. But in order for this change to occur… the Liquid R-134A requires the HEAT energy inside the air that is being blown through the Evaporator Coils...entering as Hot Summer Air… and exiting as “Air Conditioned” Cool and De-hydrated air that loses all that humidity as condensation on the Evap Coils (Beer Can Cold if the “Phase Change” is working) to drain out under the vehicle outside on the roadway.

The Basic Automotive A/C System comes with two Safety Pressure Features in the form of a High Pressure Cut-Off Switch...usually built into the Compressor and designed to prevent over heating and over pressurizing the system beyond the normal “Head Pressure” High of around 150-175 PSIG and for the Low Side...there is a Low Pressure Cut-Off Switch designed to invoke if the refrigerant evacuates and disengage the Electro- Magnetic Clutch if the pressure on the Low Side drops below 40 PSIG from a normal of say 70-80 PSIG or so. The reason for the presence of the Low Side Cut-Off Switch is to prevent the compressor from running when there is insufficient refrigerant present inside the closed system AND because the compressor is lubricated by the PAG Oil being carried along as a mixture along with ample refrigerant… without which the compressor would soon seize up.

Your Compressor will also cycle on and off rapidly whenever there is an insufficient amount of refrigerant in the system… so after putting on your AC Manifold Gauge set and observing the pressures (which should be low on the Liquid Line (HIGH) Side. If this is the case… you could try adding in small amounts of R-134A on the Low Side Service Port… using VAPOUR ONLY… but NOT by turning the can upside down. The AC-Delco AC Compressor is designed to compress VAPOUR ONLY and if it encounters a stream of liquid it will “Slug” and can be damaged.

So as this is being done... listen for the Low Side Cut-Off Switch-to-EM Clutch as it engages and the compressor will then run almost continuously when a sufficient amount of R-134A has been added. In a worst case scenario… AutoZone sells a small can of compressed gaseous Sealant, Cooler Enhancer and PAG Oil that can be added first. But if you go this route… you will have to add at least a small amount of R-134A immediately afterwards… or the Schrader Valve in the Service Port will be glued solid and rendered unusable without being flushed with R-134A.

The other problem with having Water and Oxygen floating around inside the AC System is that when exposed to either HCFC (Hydro-Chloro-Flouro-Carbon) or CFC (Chlorofluorocarbon) Refrigerant Gases and Liquids… they will combine to form Hydro-Flouric Acid...which will eat away at the interior of ALL components and in particular the parts inside of the Compressor and do some serious damage.

This is Very Important:

The Best Method for purging Air, Water and Non-Condensible Gases from a recently assembled AC System is to use Dry Nitrogen. You can purchase cans of Nitrogen Flush for AC Systems for around $25.00 on eBay or at other HVAC Distributors.

NEVER USE COMPRESSED PURE OXYGEN TO FLUSH OUT THE LINES ON ANY AC-HVAC SYSTEM UNLESS YOU WANT TO DIE IN AN EXPLOSION! ANYONE ATTEMPTING THIS WILL CONVERT THEIR AC SYSTEM INTO A BOMB!

The presence of Pure O2 (usually tried from the Green Tank of an Oxy-Acetylene Welder’s Kit) inside a system with PAG oil under pressure can cause the oil and refrigerant to spontaneously ignite, burn and then explode all of the components into shrapnel.

This is a link to a “How To R&R Auto AC” that I penned years ago on another GM Forum that has a more organized approach to doing this entire repair:

http://60degreev6.com/content.php/138-Air-Conditioning-System-Replacement-Tips
 
Last edited:

Hobbyist4Life

Original poster
Member
Sep 5, 2016
94
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Just to confirm that it's a TrailBlazer you have and not a Blazer (the older smaller type) and short wheel base (5 passenger).

The amount of refrigerant sounds about right (I got 0.85Kg). The oil depends on which components are replaced or drained of oil.
Accumulator: 60ml
Compressor: 60ml
Condenser: 30ml
Evaporator: 90ml
total oil capacity: 240ml

You may have put too much oil by possibly 30ml since the condenser is the only component that wasn't replaced. I don't think it's a problem.

When it's running, is the accumulator cold, even when blowing hot air? If so, I believe that a blend door actuator may be defective.

Or if it's first cold then warms up while idling, then the fan clutch is suspect. Test it. Also check the relay.
How to test the electro-viscous fan clutch

Sorry for the very, very late reply but I've been busy.

First, the evaporator was never changed. The core was clogged and we got it to open using petrol and compressed air, then we cleaned the condenser, which means there is absolutely no oil in anything in the a/c system.

I don't have too much oil, and that's because the person who fills gas put 100ml instead of the 240ml I told him to put.

All blend door actuators are working fine.

The accumulator gets cold only when the a/c is blowing cold air, and it does that whenever it wants.

What's happening is this:

I start the car and drive it with a/c on, it blows hot/warm air, and SUDDENLY, the vent air increases and it starts blowing ice cold air.

That "suddenly" could be at any time, could be after 5 mins of running the car, or could be after 2 hrs or even more to get ice cold.

For example, I've been driving in the streets today for like 4 hrs, and it never got cold. Not even at night.

I didn't test the fan yet, but I don't think that it's the problem.

My father reminded me that the condenser was changed with a used one off of a junkyard trailblazer after an accident that was like 2 years ago, and I'm suffering with a/c ever since. Or at least, that's what I believe.

Could the condenser be the problem?
Knowing that when you spray it with water, the a/c blows ice cold air?

What's getting me crazy is how is it possible that it starts cooling only when the air coming out of the vents increases?
What is making it increase? And by increase, I mean like DOUBLES the amount of air coming out.

Another strange thing is, the passenger's vent in the center of the dashboard is the one that's blowing coolest, highest amount of air at all times, which also drives me crazy because if I don't keep it aimed at my side, I almost feel like the a/c is off or on very low ( speed 1~2 ) while it's actually on speed 5. :crazy::Banghead::undecided:

Regards,
Hobbyist4Life
 
Last edited:

Hobbyist4Life

Original poster
Member
Sep 5, 2016
94
Qatar
Please forgive many of these questions if they seem too obvious to ask… but diagnosing your present HVAC problems can be difficult without knowing the answers to the following issues:

(1) After installing all of your OEM AC-Delco components and adding PAG Oil… prior to introducing the proper weight of R-134A Refrigerant… Did you use a Two Stage Scroll Vacuum Pump to evacuate atmospheric air, moisture and non-condensible gases? (...about $100 @ Harbour Freight)

(2) If the answer to the above is YES… Did you attach an Auto HVAC Manifold Gauge (.. also available at HF) prior to pumping the system down and confirm that the system was capable of holding a vacuum with minimal loss of vacuum over a 30 Minute Period?

If the answers are all NO...Then these other symptoms can be explained as follows and unfortunately... must begin with replacing the PAG Oil and the Accumulator and then flushing the system... without flushing the New Compressor...BEFORE moving on as they will already be contaminated with too much moisture and MUST GO:

Even with all Brand New High Quality OEM Parts, Components, Refrigerant and Lubricants… without vacuuming out all of the Moist Air and Non-Condensible Gases present in the atmosphere inside the Truck’s entire AC System… the AC will NEVER cool. The reason for this in a word is this: WATER. Even microscopic amounts of water hidden or lodged anywhere in the system will eventually FREEZE and plug up the points inside the system where the compressed Liquid Refrigerant is supposed to undergo a “Phase Change” from being a solid stream of Warm Liquid Refrigerant… and FLASH over into a GAS.

This process happens on the other side of the Orifice-Filter Tube at a proscribed rate so that the liquid phase changes inside the Evaporator Coil in just the right way… under the dashboard of your truck. But in order for this change to occur… the Liquid R-134A requires the HEAT energy inside the air that is being blown through the Evaporator Coils...entering as Hot Summer Air… and exiting as “Air Conditioned” Cool and De-hydrated air that loses all that humidity as condensation on the Evap Coils (Beer Can Cold if the “Phase Change” is working) to drain out under the vehicle outside on the roadway.

The Basic Automotive A/C System comes with two Safety Pressure Features in the form of a High Pressure Cut-Off Switch...usually built into the Compressor and designed to prevent over heating and over pressurizing the system beyond the normal “Head Pressure” High of around 150-175 PSIG and for the Low Side...there is a Low Pressure Cut-Off Switch designed to invoke if the refrigerant evacuates and disengage the Electro- Magnetic Clutch if the pressure on the Low Side drops below 40 PSIG from a normal of say 70-80 PSIG or so. The reason for the presence of the Low Side Cut-Off Switch is to prevent the compressor from running when there is insufficient refrigerant present inside the closed system AND because the compressor is lubricated by the PAG Oil being carried along as a mixture along with ample refrigerant… without which the compressor would soon seize up.

Your Compressor will also cycle on and off rapidly whenever there is an insufficient amount of refrigerant in the system… so after putting on your AC Manifold Gauge set and observing the pressures (which should be low on the Liquid Line (HIGH) Side. If this is the case… you could try adding in small amounts of R-134A on the Low Side Service Port… using VAPOUR ONLY… but NOT by turning the can upside down. The AC-Delco AC Compressor is designed to compress VAPOUR ONLY and if it encounters a stream of liquid it will “Slug” and can be damaged.

So as this is being done... listen for the Low Side Cut-Off Switch-to-EM Clutch as it engages and the compressor will then run almost continuously when a sufficient amount of R-134A has been added. In a worst case scenario… AutoZone sells a small can of compressed gaseous Sealant, Cooler Enhancer and PAG Oil that can be added first. But if you go this route… you will have to add at least a small amount of R-134A immediately afterwards… or the Schrader Valve in the Service Port will be glued solid and rendered unusable without being flushed with R-134A.

The other problem with having Water and Oxygen floating around inside the AC System is that when exposed to either HCFC (Hydro-Chloro-Flouro-Carbon) or CFC (Chlorofluorocarbon) Refrigerant Gases and Liquids… they will combine to form Hydro-Flouric Acid...which will eat away at the interior of ALL components and in particular the parts inside of the Compressor and do some serious damage.

This is Very Important:

The Best Method for purging Air, Water and Non-Condensible Gases from a recently assembled AC System is to use Dry Nitrogen. You can purchase cans of Nitrogen Flush for AC Systems for around $25.00 on eBay or at other HVAC Distributors.

NEVER USE COMPRESSED PURE OXYGEN TO FLUSH OUT THE LINES ON ANY AC-HVAC SYSTEM UNLESS YOU WANT TO DIE IN AN EXPLOSION! ANYONE ATTEMPTING THIS WILL CONVERT THEIR AC SYSTEM INTO A BOMB!

The presence of Pure O2 (usually tried from the Green Tank of an Oxy-Acetylene Welder’s Kit) inside a system with PAG oil under pressure can cause the oil and refrigerant to spontaneously ignite, burn and then explode all of the components into shrapnel.

This is a link to a “How To R&R Auto AC” that I penned years ago on another GM Forum that has a more organized approach to doing this entire repair:

http://60degreev6.com/content.php/138-Air-Conditioning-System-Replacement-Tips

(1) I'm not sure if it's a two stage scroll pump or not, but the shop where I filled it with gas used the a/c machine that recovers and refills oil. It does have vacuum but I don't know if it's a two stage or something else, but yes we did vacuum it before filling it up with R134a.

(2) The a/c machine has manifold gauges built in.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
If they filled it, the compressor is running all the time and it still doesn't get cold, there might be blockage somewhere. Did you pull or replace the orifice tube when you flushed the system? This would show on the gauges during the fill and the tech would have told you that there is something wrong.
 

Hobbyist4Life

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Sep 5, 2016
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If they filled it, the compressor is running all the time and it still doesn't get cold, there might be blockage somewhere. Did you pull or replace the orifice tube when you flushed the system? This would show on the gauges during the fill and the tech would have told you that there is something wrong.

The compressor is not running all the time, it cycles on & off. It's like on for 1~1.5 secs and off for like 8 secs.

Yes I did replace the orifice tube and the person who filled it is actually an electrician and he does a/c work simply because the one that used to do a/c quit and not coming back.
 

m.mcmillen

Member
Apr 29, 2016
554
Wisconsin
It sounds like you're either low on charge or the pressure switch in the accumulator is bad. To know what is going on for sure, you need to put a set of gauges on there and see what the pressures are doing. Once you do that, you can make a diagnosis and take the next step toward a repair.
 

Hobbyist4Life

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Sep 5, 2016
94
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It sounds like you're either low on charge or the pressure switch in the accumulator is bad. To know what is going on for sure, you need to put a set of gauges on there and see what the pressures are doing. Once you do that, you can make a diagnosis and take the next step toward a repair.

I'm not low on R134a, when I bypass the low pressure sensor it still cycles on/off. And the sensor is not bad as it is a new one that came with the accumulator.

Sometimes it cools in the hottest time of the day, in the morning, IF it decides to do so.
 

Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
Then the high pressure switch is cutting it off if you are bypassing the low pressure switch. A set of gauges would confirm this or that your high pressure switch is bad.

edit: how much did he put in? If he filled it with the amount for a dual system and you have a SWB truck, it's overfilled.
 
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Hobbyist4Life

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Then the high pressure switch is cutting it off if you are bypassing the low pressure switch. A set of gauges would confirm this or that your high pressure switch is bad.

edit: how much did he put in? If he filled it with the amount for a dual system and you have a SWB truck, it's overfilled.
He filled it with 860 grams exactly, I'm the one who put the numbers on the machine so I'm 100% positive about it.
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
A set of gauges would confirm this or that your high pressure switch is bad.

Still need to check your pressures. Just because the right amount was put in doesn't mean it's all good.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
If it's set to auto, it may sense the colder output air temp and increase the fan automatically. It may also be opening the recirculation door making it seem like it's increasing.
 

Hobbyist4Life

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Sep 5, 2016
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If it's set to auto, it may sense the colder output air temp and increase the fan automatically. It may also be opening the recirculation door making it seem like it's increasing.

I have a manual control and not auto, and I believe I don't have ambient air temp sensor.
 

Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
Ah. Well, I'm out of ideas on that one.
 

zephyr429

Member
Mar 7, 2013
29
I literally just had my AC rebuilt. My problem was my compressor was on its way out. It would blow cold occasionally. But most times it would blow hot, or start cold then hot around 20 minutes after it was turned on. After I had it replaced it worked fine but would occasionally blow hot. I found this to be a bad pressure switch not allowing the compressor to cycle and causing the system to freeze up. Once I changed the switch the system the new compressor keeps the air blowing ice cold.
 

Hobbyist4Life

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Still need to check your pressures. Just because the right amount was put in doesn't mean it's all good.

I've finally got some readings, 35°C, 45% humidity.

Low pressure: 55
High pressure: 250

This is when the A/C was blowing hot.

I literally just had my AC rebuilt. My problem was my compressor was on its way out. It would blow cold occasionally. But most times it would blow hot, or start cold then hot around 20 minutes after it was turned on. After I had it replaced it worked fine but would occasionally blow hot. I found this to be a bad pressure switch not allowing the compressor to cycle and causing the system to freeze up. Once I changed the switch the system the new compressor keeps the air blowing ice cold.

Which pressure switch was it? low pressure or high pressure?

Edit: I have a suction sound that could be heard if you stand near the passenger's side fender, which I believe is coming from where the orifice tube goes.

Some people told me that it's normal, but is it? I don't think so... Thoughts?
 

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mrrsm

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This may not sound right... But on one or two occasions I have seen some "Orifice Tubes" unintentionally, accidentally installed BACKWARDS under circumstances where the "Alignment and Crimp Stop" were set deep enough to allow a "Wrong Way" install to occur and the Orifice Tube fed in past the Mating Flange, looking normal enough to be closed back up.

The Screen Tapered Cone should be facing AWAY from the Inlet Side of the Evaporator. The other aspects of problems like this involved dislodged debris working its way through the system as far as it can migrate and interrupt the flow of the refrigerant:


On a GM Vehicle:


The ONLY value this video has is demonstrating that: EVEN IF YOU PUT IN A BRAND NEW ORIFICE TUBE...IF YOU FAILED TO FLUSH ALL OF YOUR LINES WITH AN HVAC FLUSH KIT... AS SOON AS YOU FIRE UP THE AIR CONDITIONING...ALL OF THE FREED UP DEBRIS WILL MIGRATE AROUND THE SYSTEM AND ONCE CONDENSED BACK INTO A LIQUID...WILL RE-CLOG THE NEW ORIFICE TUBE.

PLEASE ...NEVER USE A COMBUSTIBLE FLAMMABLE FUEL GAS LIKE PROPANE TO BLOW OUT OR PRESSURE TEST YOUR AC SYSTEMS! YOU CAN GET CANS OF INERT DRY NITROGEN FROM EBAY FOR $25.00 AND BE MUCH SAFER AND HAVE A DRIER AND CLEANER SYSTEM, TOO:

 
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Hobbyist4Life

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Sep 5, 2016
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This may not sound right... But on one or two occasions I have seen some "Orifice Tubes" unintentionally accidentally installed BACKWARDS under circumstances where the "Alignment and Crimp Stop" were set deep enough to allow the "Wrong Way" install to occur and the Orifice Tube fed in past the Mating Flange looking normal enough to be closed back up.

The Screen Tapered Cone should be facing AWAY from the Inlet Side of the Compressor. The other aspects of problems like this involved dislodged debris working its way through the system as far as it can migrate and interrupt the flow of the refrigerant:


On a GM Vehicle:


The ONLY value this video has is demonstrating that: EVEN IF YOU PUT IN A BRAND NEW ORIFICE TUBE...IF YOU FAILED TO FLUSH ALL OF YOUR LINES WITH AN HVAC FLUSH KIT... AS SOON AS YOU FIRE UP THE AIR CONDITIONING...ALL OF THE FREED UP DEBRIS WILL MIGRATE AROUND THE SYSTEM AND ONCE CONDENSED BACK INTO A LIQUID...WILL RE-CLOG THE NEW ORIFICE TUBE.

PLEASE ...NEVER USE A COMBUSTIBLE FLAMMABLE FUEL GAS LIKE PROPANE TO BLOW OUT OR PRESSURE TEST YOUR AC SYSTEMS! YOU CAN GET CANS OF INERT DRY NITROGEN FROM EBAY FOR $25.00 AND BE MUCH SAFER AND HAVE A DRIER AND CLEANER SYSTEM, TOO:


The orifice tube was installed the aame way the old one was installed. The long side facing the front of the vehicle, and the short part facing the firewall.

We've cleaned both the evaporator and the condenser using petrol and compressed air back when everything was disassembled. After getting them dry we put everything back together and here we are.
 
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mrrsm

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Delphi wrote up a TSB on a Problem they were having with their Low Pressure Switches with intermittent Hot and Cold Air Blowing on numerous GM Models that may be relevant here... and they have some good graphics and a simple "Tap Test" on the LPSW that can be tried as well:

http://speedwayautoparts.com/Intermittent no AC or AC blows warm.pdf


EDIT:

If the above link is "sketchy"...I have screen prints of both pages of the TSB attached as images:DELPHISWITCHTSB1.jpeg DELPHISWITCHTSB2.jpeg
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
@MRRSM, the OP has said that the compressor is running continuously so the low pressure switch is not at play here.

I have an issue with using "petrol" to flush an A/C system. Even if it is "dry", it would likely leave an oily film. Real flush is made with solvents, which evaporates and leaves nothing. Gasoline, even after it has evaporated, leaves a smell, which means it leaves behind something.

Besides, because of the design of A/C parts nowadays, especially the condenser, flushing doesn't work anymore:

As for the evaporator, found this bit of info at http://www.aircondition.com/tech/questions/25/:

" Question: Should the evaporator be flushed?
Answer: Most would say yes, but some would argue that it's not worth the extra effort for two reasons. Flush solvents can be very difficult to remove from some evaporators. Sometimes the risk of not being able to remove the solvent outweighs the benefit of flushing that component. Secondly, some would point out that evaporators stay fairly clean because any dirt floating around the system is captured first by the receiver drier, then by the inlet screen of the expansion valve. In the case of an orifice tube system, most debris would be caught by the orifice tube screens before it could reach the evaporator. While this is mostly true, systems that use the block style expansion valves have no inlet screen, and dirt from a ruptured receiver drier could find its way into the evaporator. Also, oil likes to accumulate in low-lying areas of the evaporator. If your goal of flushing is to remove dirty oil, you'll have plenty of it in your evaporator. "

So really, the only thing that could benefit from flushing are the hoses. The shop that did the work for you did not know what they were doing. If I would have gone to all that trouble of removing the dash to get to the evaporator, I would have just replaced it.

Sorry if I'm blunt but I think your system is just contaminated. If the evaporator was contaminated as you say it was, the system was likely suffering from black death, possibly due to past improper repairs, if it made it past the orifice tube.
 

Hobbyist4Life

Original poster
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Sep 5, 2016
94
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Delphi wrote up a TSB on a Problem they were having with their Low Pressure Switches with intermittent Hot and Cold Air Blowing on numerous GM Models that may be relevant here... and they have some good graphics and a simple "Tap Test" on the LPSW that can be tried as well:

http://speedwayautoparts.com/Intermittent no AC or AC blows warm.pdf


EDIT:

If the above link is "sketchy"...I have screen prints of both pages of the TSB attached as images:View attachment 78637 View attachment 78638

Mine is ACDelco and not Delphi...

And even if I bypass the low pressure switch the Compressor still cycles or not work at all.

@MRRSM, the OP has said that the compressor is running continuously so the low pressure switch is not at play here.

I have an issue with using "petrol" to flush an A/C system. Even if it is "dry", it would likely leave an oily film. Real flush is made with solvents, which evaporates and leaves nothing. Gasoline, even after it has evaporated, leaves a smell, which means it leaves behind something.

Besides, because of the design of A/C parts nowadays, especially the condenser, flushing doesn't work anymore:

As for the evaporator, found this bit of info at http://www.aircondition.com/tech/questions/25/:

" Question: Should the evaporator be flushed?
Answer: Most would say yes, but some would argue that it's not worth the extra effort for two reasons. Flush solvents can be very difficult to remove from some evaporators. Sometimes the risk of not being able to remove the solvent outweighs the benefit of flushing that component. Secondly, some would point out that evaporators stay fairly clean because any dirt floating around the system is captured first by the receiver drier, then by the inlet screen of the expansion valve. In the case of an orifice tube system, most debris would be caught by the orifice tube screens before it could reach the evaporator. While this is mostly true, systems that use the block style expansion valves have no inlet screen, and dirt from a ruptured receiver drier could find its way into the evaporator. Also, oil likes to accumulate in low-lying areas of the evaporator. If your goal of flushing is to remove dirty oil, you'll have plenty of it in your evaporator. "

So really, the only thing that could benefit from flushing are the hoses. The shop that did the work for you did not know what they were doing. If I would have gone to all that trouble of removing the dash to get to the evaporator, I would have just replaced it.

Sorry if I'm blunt but I think your system is just contaminated. If the evaporator was contaminated as you say it was, the system was likely suffering from black death, possibly due to past improper repairs, if it made it past the orifice tube.

The compressor is not continously running, it goes on and off. But when it cools it stays on.

If I tell the Compressor to stay on using autel ds708, or gm tech 2, the Compressor stays on but it doesn't cool.

The evaporator was completely clogged for some reason, so it had to be opened.

I took the dash apart myself and I can do it again, so I don't care that much about the hassle.

The weather is nice these days so the a/c is working most of the time.

I plan on replacing the evaporator and condenser when I get the time and money.

Replys about suggestions will be slow because I hit the car in front of me and he had a long tow hook and it bent my condenser.

It doesn't seem to be leaking so... Yea.
 
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Mooseman

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Dec 4, 2011
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Ottawa, ON
My recommendation still stands that I think the system is clogged and/or contaminated. Your condenser will need to replaced and if your evaporator was once clogged, it should be replaced and the hoses flushed. (I'm talking internal clog, not external i.e. fins)
 

Hobbyist4Life

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My recommendation still stands that I think the system is clogged and/or contaminated. Your condenser will need to replaced and if your evaporator was once clogged, it should be replaced and the hoses flushed. (I'm talking internal clog, not external i.e. fins)

Does it mean anything if there is too much water dripping from a/c?!

The pic is after 1~2 mins parking while a/c is cooling
 

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mrrsm

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The amount of Condensate that will flow down and out the Evaporator Drain Tube is conditional on how much Humidity there is in the Ambient Air that makes contact with any Cold Components above the Drain Pan or Collector Pipe. Ergo... if two identical TBs are parked for 1-2 minutes with one located in South Florida on practically any day of the year and the other in the Colorado Rocky Mountains... The one in Florida will be haemorrhaging cold water from a parked, idling vehicle... while the other one in the Rockies will hardly show anything at all coming out onto the parking lot.

From looking at the pool under your vehicle... I'd suggest catching the contents of what is exiting the drain in a small White Plastic Bucket... and see if you observe or smell any PAG Oil or Oily Residue... as it will strongly indicate a pin-hole leak somewhere in the Evaporator Coil itself and the residue being picked up and carried along as the water vapour condenses on the coils and drains downward by gravity. Please be careful if you see any kind of Black or Slimy Mold present...as the Legionella Organism that can thrive in Cold AC Drain Water causes Legionnaire's Disease and may be present in the Cold Liquid Condensate.

About the Trailer Hook denting into the Condenser.. You don't say whether of not that incident preceded your AC malfunction... but if this is true in this case....the Condenser Lines may have been squashed or pinched just enough to restrict the "sub-cooling" function of the Compressor to convert the returning Refrigerant Vapour from a gas into a liquid.... and the intermediate period of enough liquid making it up and through the Liquid Line to expand through the Orifice Tube would be a likely outcome of "Throttling" the Coolant.

Its important to remember that you have a Refrigerant trying to make its way in one, single direction throughout the entire A/C System...where the Changes of State necessary to make the Gas Vapour condense into a Liquid and then expand right back into a Gas again. If it is out of synchronisation because of if any of the piping is either leaking... or being squeezed down in its internal diameter to further restrict the flow... the these changes of state will happen either prematurely or not at all. Right now...as suggested by @Mooseman BOTH of these Major AC Components could be having problems...independent of one another.
 
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Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
The condensate water is an important clue. This means that your evaporator is cold enough to create condensation. Have you checked the temperature blend door actuators? If they're not working properly, they could be blending in warm air even though air is still passing through the evaporator. First, try pulling the HVAC-B fuse for a minute, put it back in, turn the key to Run but don't start the engine. Let the system reset and recalibrate the actuators for a couple of minutes. See if it improves. If not, your actuator(s) may be defective.
 

Hobbyist4Life

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The amount of Condensate that will flow down and out the Evaporator Drain Tube is conditional on how much Humidity there is in the Ambient Air that makes contact with any Cold Components above the Drain Pan or Collector Pipe. Ergo... if two identical TBs are parked for 1-2 minutes with one located in South Florida on practically any day of the year and the other in the Colorado Rocky Mountains... The one in Florida will be haemorrhaging cold water from a parked, idling vehicle... while the other one in the Rockies will hardly show anything at all coming out onto the parking lot.

From looking at the pool under your vehicle... I'd suggest catching the contents of what is exiting the drain in a small White Plastic Bucket... and see if you observe or smell any PAG Oil or Oily Residue... as it will strongly indicate a pin-hole leak somewhere in the Evaporator Coil itself and the residue being picked up and carried along as the water vapour condenses on the coils and drains downward by gravity. Please be careful if you see any kind of Black or Slimy Mold present...as the Legionella Organism that can thrive in Cold AC Drain Water causes Legionnaire's Disease and may be present in the Cold Liquid Condensate.

About the Trailer Hook denting into the Condenser.. You don't say whether of not that incident preceded your AC malfunction... but if this is true in this case....the Condenser Lines may have been squashed or pinched just enough to restrict the "sub-cooling" function of the Compressor to convert the returning Refrigerant Vapour from a gas into a liquid.... and the intermediate period of enough liquid making it up and through the Liquid Line to expand through the Orifice Tube would be a likely outcome of "Throttling" the Coolant.

Its important to remember that you have a Refrigerant trying to make its way in one, single direction throughout the entire A/C System...where the Changes of State necessary to make the Gas Vapour condense into a Liquid and then expand right back into a Gas again. If it is out of synchronisation because of if any of the piping is either leaking... or being squeezed down in its internal diameter to further restrict the flow... the these changes of state will happen either prematurely or not at all. Right now...as suggested by @Mooseman BOTH of these Major AC Components could be having problems...independent of one another.

The condenser proble is fresh, about a week ago. My problem is long ago!

The condensate water is an important clue. This means that your evaporator is cold enough to create condensation. Have you checked the temperature blend door actuators? If they're not working properly, they could be blending in warm air even though air is still passing through the evaporator. First, try pulling the HVAC-B fuse for a minute, put it back in, turn the key to Run but don't start the engine. Let the system reset and recalibrate the actuators for a couple of minutes. See if it improves. If not, your actuator(s) may be defective.

I have to make things clear, I work part time as the scanner guy in the same garage that did my evaporator, and I have access to autel ds708 and tech2 and vcm2 and some other oem scanners.

I have already tried recalibrating all actuators and they are fine. And as I said that picture was when it was actually cooling, I didn't check when it's not cooling but I do know that when it's not cooling the accumulator is not cold at all so...
 

mrrsm

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Well... at THIS juncture... Your best option is to Flush the Evaporator Coils AND the Condenser Coils... as Separate...Disassembled components using TWO of these Kits. The thing to remember is that the Rubber Hose Lines mated to all of the Aluminum Piping in all A/C lines are specially coated inside in order to reduce the chances of the tiny molecules of the Refrigerant from escaping. Using Gasoline... (or Petrol as you described it) may have damaged the coatings inside the hoses and lines and allow them to break down and release particles into the PAG Oil and Vapour Stream that will clog and damage other components inside the entire system. DO NOT FLUSH THESE COMPONENTS THROUGH THE COMPRESSOR... THESE CHEMICALS WILL RUIN IT!

If your Evaporator was installed as a Brand New Unit ...but your Old Condenser was left in place and was clogged ...then BOTH have since been contaminated with junk left in the Condenser while the AC System has been running, Consequently... They are BOTH in need of THIS stuff. You do NOT need to remove the Evaporator Unit from under the Dash OR the Condense Coil from The Radiator Area to do these Flushing Jobs...but you WILL Need to arrange Hosing and a Bucket to allow the crap that is being Blown In...and then... Out to get collected. The idea here is to pressurize the system by following the instructions in the Link below...and use clamps on some Clear Acrylic or Clear PVC Hosing from the Out Ports to guide the Dirty Cleaning Fluids down into the Catch Bucket in a Well Ventilated location. DO NOT FLUSH THE LINES WITH THE ORIFICE TUBE INSTALLED OR THE ACCUMULATOR INSTALLED...THEY MUST BE REMOVED FIRST!

Once again...a Brand New Orifice Tube. Brand New Accumulator and Fresh PAG Oil in the Correct Amounts are a MUST after doing this DUAL FLUSH. It follows on that you will still need to evacuate the system down to a near perfect vacuum after blowing out the components and lines with either Dry Nitrogen ...or Compressed Air before charging the system with a proper weight of R-134A. More instructions specific to this Product are lower down on this site page:

http://www.ebay.com/gds/How-to-Clea...aporator-/10000000178532973/g.html?rmvSB=true
 
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Hobbyist4Life

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Sep 5, 2016
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Hello,

Sorry for the VERY late reply, but the A/C has been fixed.

The condenser was clogged and I replaced it with a new ACDelco one, and the climate controller seemed to lose connection with other components from time to time, making actuators get out of calibration every now and then.

Fixed that and everything is working perfectly.

Thank you so much for all the help that you provided while diagnosing my problem with the A/C.

Regards,
Hobbyist4Life
 

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