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NEW Compressor and still does not blow cold. PLEASE HELP. Pages: 12

slantdawg on Sat July 11, 2009 1:50 PM User is offline

Year: 2001
Make: Oldsmobile
Model: Aurora
Engine Size: 3.5
Refrigerant Type: 134
Ambient Temp: 90
Pressure Low: 60
Pressure High: 200-250
Country of Origin: United States

So I replaced the compressor after two shops said that it was the problem and I'm still getting the same readings as I was with the old compressor. I'm aggravated at the moment and can use a hand.

The problem is the low side pressure never comes down past 60PSI, unless I turn the fan on low; then maybe the pressure will drop to around 50. The temp out of the middle vent is about 60 to 70 degrees. I have this same problem with a Brand NEW A/C Delco compressor.

One thing I noticed with both the new and old compressor is when I had them out of the car, I spun them and I cannot feel any suction or pressure with my hand over the ports. This is the same for the new compressor. Am I expecting too much? Does it take a fast RPM to feel any suction? Also, there is no drag on both compressors what so ever. I use to remember going to the junk yard with my dad and looking for compressors and we use to spin them to see if they felt like they had too much drag and would usually pick one that you could spin by hand. They both are easy to spin.

I live in Florida and both lines to and from the evaporator feel cold and are sweating like crazy, but the pressures and lack of cold air inside the car make me belive there is a problem

And If it's not the compressor, what the heck else could it be. I replaced the compressor, replaced the accumulator, replaced the screen in front of the electronic orifice valve and added 8oz. pag 150 oil and 35oz of 134a. I vacuumed the system twice for about 1 hour each time, down to 29in.


Edited: Sat July 11, 2009 at 2:18 PM by slantdawg

TRB on Sat July 11, 2009 2:54 PM User is offlineView users profile

Was the system ever flushed to remove the original oilr?


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slantdawg on Sat July 11, 2009 3:29 PM User is offline

the system was not flushed. I was going to flush it, but I didn't for two reasons. First was because when I took out the old compressor, there was no oil in the compressor at all.The screen inside the system, right before the expansion device had a tiny amount of debris, but nothing that looked severe.

I noticed that the seal on the front of the compressor looked like brown mud, so I think oil was leaking there. Since refrigerant carry's the oil, I thought there should be some oil in the compressor if there was any in the system.

Second was because I did n't think I would be able to get all the flush out of the evap and/or condenser because of it being a parallel style condenser.

One thing I noticed is when I took off the high side hose, there was still some pressure in the hose and I saw a green color oil come out and seemed like about a cap or two of oil. The oil I put in the system was blue, so I guess there was something still in the system.

One thing that always confused me is the location of the low and high service ports on this car. Maybe someone can chime in and help me understand this. On every other car I have ever worked on, the low side service port was between the compressor and the evaporator and the high side service port was between the compressor and the condenser. On this car, the ports are between the evap. and the orifice and the high side is between the orifice and the condenser.

Question 1. Because of the placement of the ports, wouldn't the pressure readings be different?
Questions 2. Do you think there is too much oil in the system and that is why she is not getting low on the low side?

The low side pipes are cold, but I cannot tell what tempature, so they may not be cold enough, but they feel cold and they are sweating

With both compressors, when I rev the engine, I cannot get the low side needle to move much. On most cars I've seen, when you rev the engine, the needle on the low side gauge usually mores pretty quickly. This was one of the reasons the compressor was replaced in the first place.


QuestionsAre you thinking that there is too much oil in the system?

TRB on Sat July 11, 2009 3:36 PM User is offlineView users profile

Could be too much oil or bad expansion device. But since you swapped compressors and added back 8 ounces I would be concerned with too much oil. Flushing is not just for debris removal. It's the proper way in my opinion to get a system filled to the proper specifications. It's not like a/c system have a dip stick we can use to check the oil level!


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slantdawg on Sat July 11, 2009 4:49 PM User is offline

thanks TRB..I understand that if too much oil is in the system, it replaces the refrigirant. Do you think this would keep the low side of the system from getting down to where it should be, which I would think would be 30 to 40 psi??

As far as the expansion device, it's not a true expansion valve. It does not operate on pressure, but is electric. I belive when the pressure on the high side is too high, it opens up the expansion valve and allows more refrigirat through??

slantdawg on Mon July 13, 2009 5:27 PM User is offline

brought the car down to the ice cold air place and then don't even know whats wrong.. I guess that makes me feel a little better about myself. Guy says he has never seen an electric orifice valve before like the one I have...great.. I have something that sounds like I'm going to have to get the dealer involved to troubleshoot..

Once again, at idle, 88 degrees outside, low side around 60, high side around 220, raise the idle, low side still around 60, high side at 250. Let off the gas and the high side comes back down..low side stays the same??


slantdawg on Mon July 13, 2009 6:59 PM User is offline

I just checked the pressures again and it's 55 psi low side and 175 high side at idel. Give it some gas and the high side will raise all the way to 250 but the low side drops to about 50psi; never will it go lower then that. I let out a little freon and still it does not seem to drop..

Could I have possbily bought a brand new bad compressor.. like I said earlier, booth the old and new compressor did not seem to have an suction or pressure on them when I was turning them by hand..does anyone with experience know if I should feel some sort of suctions when turning by hand?

iceman2555 on Tue July 14, 2009 12:25 AM User is offlineView users profile

Turning these compressors by hand may not produce the expected pressure one would expect. They must be rotated very fast to produce pressures. This vehicle uses the MSC105CVSG1 type compressor. When this compressor produces a vast amount of debris within the system. The statement that there was no lube in the compressor is cause for concern, this is normally the result of operation of an undercharged (leaking) system. This condition is also a cause of the debris within the system.
The probable problem with this vehicle is that the condenser of this vehicle is restricted. This is not an uncommon problem with failures of this type compressor and the newer more efficient PFHE condenser. Unfortunately, this condenser is not going to flush clean, at least, not without the use of specialized equipment. Check with Hecat..he has a flush machine that will do wonders. However, if the condenser can not be flushed it should be replaced. The low or acceptable high side pressures and the higher low side pressures are indicative of a restricted condenser. This is, of course, assuming that the system is fully charged. How was the system charged...with the proper recharge equipment or some other method?
One test would be to bring the vehicle up to N.O.T, allow the system to operate for app 5-7 minutes (to stabilize the system). Using a temp probe/laser temp gun (ugh) measure the inlet and outlet temps of the the results. It is better to use some type of contact temp probe...they simply work better.
All in all, we are seeing more problems such as yours this year...and the majority can be traced back to condenser restrictions.
Good luck!!!!

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Thomas Jefferson

JJM on Tue July 14, 2009 3:35 AM User is offline

I don't like the fact that the compressor didn't have oil when you removed it, but since you found little debris on the electronic orifice valve screen, you might have rescued the system in time.

High low side pressures and excessive evaporator sweating are signs of a flooded evaporator. Problem is you're in Florida, so there's likely high humidity which will also result excessive evaporator sweating, but those pressures still point to a problem.

Ideally, you need a Tech II to test the system, not only to check for codes, but so you can command the electronic orifice valve and relay. But here's a quick check you can do: Run the engine at around 3,750+ RPM and check you pressures. Disconnect the electronic orifice valve. You should see a pressure change and change in vent temps. If there's no pressure change, there's likely a problem with the orifice or relay.

Check for +12V at the electronic orifice valve at both idle and around 3,750 RPM voltage. If there's never any voltage, check the relay, but there might not be voltage due to a code caused by a bad sensor, or the DIM module.

You can also try applying +12V fused and a ground to the electronic orifice valve directly and seeing if pressures and vent temps change. If it does, at least you know the valve is good, and the problem is electrical, and we can take it from there.


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HECAT on Tue July 14, 2009 10:09 AM User is offline

This does not seem to be a compressor failure (metallic debris) as the original compressor was running and little debris was seen in the screen. However, the condenser is a primary filter and then the filter/dryer, which will usually not allow much debris through to the TXV screen; many manufacturers do not even use a screen at the TXV. This can produce a deceiving assumption from the condition of the screen. A simple test would be a quick back blow air shot ("Pop") to the condenser into a clean rag, this would present evidence of metal (if it exists) and the need for a good flush (thanks Iceman-checks in the mail) or condenser replacement.

The original oil charge (or most of it) was still in the system even though the compressor did not still retain much. Many compressor won't depending on the final operation of the system before recovery. A little may have leaked from the shaft seal (mud trace) and a little may have come out with recovery; but the rest of it was still in there. Where could it go? It does not evaporate or become consumed by the system. Then another system oil charge was added and it is definitely now oil overcharged which alone can produce the higher low side pressure readings and increased vent temps. I don't think it can be ruled out that although the symptoms are similar; the problem or cause may now be different.

The port locations is usually not an issue as the high side and low side are separated at 2 points, the compressor and the orifice and basically the pressures can be read anywhere on the high or low side between those points. However, with this port configuration there may be higher head pressures (indicating condenser restriction) than are being seen due to the reading of the high pressure after the condenser; and the higher low pressure readings seem plausible when considering this reading is being taken on the inlet side of the evaporator (?).

The concerns about flushing properly are valid; if you don't do it properly, it won't work. Unsatisfactory results breed the "it can't be done" talk. That spray can label said it was good stuff; should we expect them to print the inadequacies of their product on the label? Its not about the component design its about doing something that will work on that particular component design. Ignoring the need or just skipping over that part of the process is not the answer either. I think of it this way: If engine oil was difficult to remove and required special equipment; would we seek out a pro with such equipment, purchase it ourselves to DIY, replace the engine, or just skip it and add some fresh oil


HECAT: You support the Forum when you consider for your a/c parts.


GM Tech on Tue July 14, 2009 10:45 AM User is offline

The following may help you (and your a/c shop) understand the Aurora system...

One thought- maybe your OT solenoid is stuck on the big Orifice- thus lower head and higher suction pressures......

Another thought- You can't expect to "suck in a plastic bag" (or your thumb) on your Mitsubishi scroll type of compressor- when turning it on the bench...That test usually only works for fixed displacement piston type compressors- not on your scroll type compressor or on a variable stroke unit....I think you changed your compressor unnecessarily- now you have a spare.

From the GM service manual........

Dual-Stage Orifice
The purpose of the dual stage orifice is to extend the operating range of the A/C system. The DIM energizes the HVAC solenoid by grounding the A/C orifice relay control circuit. If the DIM energizes the HVAC solenoid, the ignition 3 voltage is supplied to the A/C orifice solenoid through the A/C orifice solenoid supply voltage circuit. The valve allows the compressor to stay on by reducing compressor head pressure during warm to hot ambient drive away conditions. With the valve, a typical head pressure reduction of approximately 276 kPa (40 psi) can be expected during rapid acceleration. The valve reduces compressor cycling under mild ambient conditions. The valve is electronically controlled and the orifice size is determined by the position of a solenoid plunger. The diameters are:

• Valve energized or ON, the plunger moves to the 1.57 mm (0.062 in) orifice size.

• Valve de-energized or OFF, the plunger moves to 2.03 mm (0.080 in).

The DIM commands the orifice valve relay using the following four Class 2 data inputs.

• A/C compressor clutch state

• High side pressure is within 1138 kPa (165 psi) to 1793 kPa (260 psi)

• Engine RPM

• Vehicle speed

The valve will remain OFF when the ignition or the A/C system is OFF. Any one of the following limits will turn the valve to the OFF position.

• A/C compressor clutch disengagement

• High side pressure falls below 931 kPa (135 psi).

• High side pressure exceeds 2620 kPa (380 psi).

• Engine speed exceeds 3500 RPM.

• Vehicle speed exceeds 101 km/h (63 mph

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Edited: Tue July 14, 2009 at 12:01 PM by GM Tech

slantdawg on Tue July 14, 2009 6:23 PM User is offline

thanks Everyone for your help. To answer some of your questions....

The orifice valve is working electrically..when the car is at idle and I unplug the orifice, I can fell the solenoid click and I can also see a increase in pressure. WhenI plug it back in, I feel anpother click and then the pressure drops.

My questions was when the solenoid is in the closed position, is it closing all the way?? And if not, is that enought to flood the evaparator.

I did not know that a clogged condensor would cause this condition. if anything, I thought a clogged condensor would cause a high pressure on the high side( due to the restrictions) and a low pressure on the low side (due to the lack of refrigirant)

The system was vacummed with a 2cfg pump for 2 hours. Then I added 1 12oz can with the car off. Then started the car and added the other 2 cans, tap in the up position to keep liquid from entering the system

GM Tech on Tue July 14, 2009 8:30 PM User is offline

There might be high , high side pressure, you would never see it because your gage port is behind the condenser-- and so is the HPCO transducer - so if it were really high, it would blow the pressure relief valve on the compressor-- but it may be high enough to cause your concerns...

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

slantdawg on Wed July 15, 2009 7:26 AM User is offline

thanks again for everyones input. I think the location of the low side and high side service ports has helped me mis-diagnose this issue. I guess I may have replaced the compressor and that wasn't necessary, but then again I did see a mud like color on the front of the compressor, so it looks like it was leaking oil and refrigirant.

My wife says it's time to take it to the mechanic.

I think you guys are right in that the condensor is probably the issue. From what I'm hearing, the condesnor is restricted, but not all the way, so all the heat is not being removed from the refrigirant, causing the pressures to be high and because my high side service port is after the condensor, I may not being getting a true representation of what really is going on on the high side.

I promise that once this is fixed, I will let everyone know what corrected the issue.


JJM on Wed July 15, 2009 9:10 AM User is offline

It appears the electronic orifice valve is working at idle, but have you checked it at around 1,500 to 2,000 RPM? It could be kicking out because the the DIM is seeing higher pressures (due to sensor location) than your gauges. If the electronic orifice is not doing anything at higher RPM's (below 3,500 as GM Tech pointed out), then the DIM is likely seeing high pressures (or something else).

I assume the check engine light is not on.

It is also possible the electronic orifice valve is not closing all the way, due to debris or other malfunction. I know this valve is not cheap from the dealer.

Does misting the condensor cause a drop in pressures and am increase in cooling performance? Does misting the condenser also cause the electronic orifice valve to close? If so, we're likely looking at condenser issues. Measure in the condenser inlet and outlet temperatures with an IR thermometer. The temperature should drop gradually over the coil with no cool or cold spots.


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slantdawg on Wed July 15, 2009 9:06 PM User is offline

Thanks Joe. Those are all good things that I need to check.

I do remember racing the engine and hearing the orifice valve "click" and then the low side pressure would rise even more and the high side pressure would still raise, but not as fast. Then If I let off the gas, the orifice clicks again and I see the pressure drop instantly by about 5 psi, as it starts to come back up a little, on the low side.

today the mechanic said that he pinched the heater core hose and was able to get the air to come out at 42 degrees, center vent. I didn't think this was the issue because I checked the temperature doors before I brought the car in, but I figured he is probaby right

Well, that did not seem to help. I brought the car home, pinched off the heater hose and that did not change anything, except cause my temparature gauge to show the car is overheating....besides if this was the cause, wouldn't the air come out nice and cold in the morning, when the temparature out side is warm and the engine is completely cold?

This more and more looks like it's pointing to the condensor. I mean there aren't to many parts left. I replaced the compressor, i replaced the accumalator, I replaced the orifice valve screen..that leaves the condensor, the evaparator and the orifice valve.

By the way, it seems like ACKITS does not sell anything for my car? Is that right?


Edited: Wed July 15, 2009 at 9:17 PM by slantdawg

TRB on Wed July 15, 2009 11:20 PM User is offlineView users profile

Originally posted by: slantdawg
By the way, it seems like ACKITS does not sell anything for my car? Is that right?


That section has not been updated. Just email the staff with a request and we can check availability.

When considering your next auto A/C purchase, please consider the site that supports you:

slantdawg on Thu July 16, 2009 7:49 PM User is offline

this is TOTALLY not making sense to me...

i tried misting the condensor and this seems to lower the high side pressure, from 200 to 150(this is pressure after the condensor) but does nothing for the low side, which stays around 55 psi at idle. I raise the idle to about 1300 rpm's and I get the low side down to 50 while misting the condensor. The strange thing is when we mist or soak the condensor, it brings the temparature at the outlet up about 5-7 degrees..this makes no sense to me. When I stop spraying, the temparature at the vent goes back down???I saw it my self..about 64 degrees at vent with car at 1300rpm's, 70 degrees at vent while spraying the condensor...low side pressure will never come down past 50...high side is about 150 to 250..the whole time the lines are sweating..

I even thoguht, OH could it be the haeater I pinched the lines for about 1 difference in the temparature...anyone live in the St. Petesburg, Florida area want to come fix this??

Oh and I almost matter what, ever since I got the car and the air has worked Ok, until now, the drive side air has always been warmer then the passanger.. I was told this meant the car was low on refrigirant, but I'm not thinking that the case at the moment.

Edited: Thu July 16, 2009 at 8:19 PM by slantdawg

slantdawg on Thu July 16, 2009 11:22 PM User is offline

So I found this in a Mitchell Guide...this is saying that my air is working correctly..don't these numbers seem high? Am I chasing a problem that dosen't exists? Sure dosen't cool off the car??? My low side pressure is not what they say though


AmbientHumidity Outlet Temp Low Side High Side Pressure
60(16) 0-100% 45 (7) 24-30 (1.7-2.1)158-188 (11.1-13.2)
70(21) 40% 51 (11) 28-34 (2.0-2.4)127-157 (8.9-11.0)
80(27) 60% 59 (15) 33-39 (2.3-2.7)182-212 (12.8-14.9)
90(32) 30% 66 (19) 33-39 (2.3-2.7)173-203 (12.2-14.3)
100(38) 40% 71 (22) 36-46 (2.5-3.2)196-236 (13.8-16.6)
110(43) 20% 76 (24) 45-55 (3.2-3.9)223-263 (15.7-18.5)
120(49) 30%(1) 74 (23) 50-60 (3.5-4.2)261-301 (18.4-21.2)
(1) Relative humidity is less than stated value

Edited: Fri July 17, 2009 at 8:55 AM by slantdawg

JJM on Fri July 17, 2009 10:00 AM User is offline

Makes perfect sense to me if the electronic orifice valve is stuck open, which I've been suspecting since the beginning.

The driver vent temps slightly lower than than passenger is an indication of a low charge, and by misting the condensor, you're making up for the refrigerant shortfall by ensuring more of the hot gas from the compressor is converted to a liquid. The last thing you need when an orifice is open is even more refrigerant in the evaporator. Excessive evaporator sweating (when the relative humidity is less than 60%) is an indication of a flooded evaporator.

Also, you need more than a minute after pinching the heater hoses to see results if there's a blend door issue; the heater coil needs time to cool.

The valve may be clicking, but it doesn't mean it's working properly. The electronic orifice is not cheap at over $150 list from the dealer. My concern is debris with the compressor not having oil, so before replacing it I would suggest thoroughly flushing the system and replacing the condensor, or you could end up with a repeat failure. I also suggest using an inline filter.


When considering your next auto A/C purchase, please consider the site that supports you:

slantdawg on Fri July 17, 2009 3:37 PM User is offline

thanks Joe. I've always wondered myself is the orifice was flooding the evaparator. I'm able to get the orifice for about $65, so it should not be to bad...

Would you say it's safe to say it's not the heater core problem if I start the car for the first time in the morning (engine cold) and still I only get 60 - 65 degrees at the center vent.??

I will let everyone know how it goes..

Edited: Fri July 17, 2009 at 3:42 PM by slantdawg

slantdawg on Sat July 18, 2009 6:34 PM User is offline

todays update is a little bit brighter..

The night before last, I added some freon back into the system, because I took some out after replacing the compressor, because of the low side pressure being high. I had my wife in the car, with the thermometer in the center vent. I SLOWLY added a little freon at a time, waited a couple minutes and then asked for a reading. I also would feel the pipes under the hood to see how they feel. Eventually I was at a point where adding more freon did not change the temperature, so I stopped adding freon. Temp was about 60 with fan on high.

We brought the car to another mechanic yesterday. He charged $16 to do a diagnosis which I thought was well worth it. He says the low side is at 60 and the high side is at 200. He says "your recirculate door is not working" When I heard this, a bell rang in my head. Everytime I hit that recirculate button, I never heard any louder noises nor did the air come out colder or faster. How come I dismissed this door as working? Did I think her car was special and would not make a "louder fan noise" when switching between modes? He says the low side is high because I'm trying to cool off the hot, outside air.

So I removed the glove box and sure enough the door was in the "fresh air mode" The motor may have burned up (uses electric, not vacuum). I removed the motor, closed the door and then put the motor back, so now it recirculates. I didn't think this would make that much of a difference, but I guess if you keep recooling the air, it's going to be easier then cooling the air under the hood. Last night we took a drive and with the air on full blast, we got down to 44 degrees.

Today, was the true test, (93 outside) ... it cools of the car, but it akes a while for the temperature to come down at vent (5-10 minutes)..much better though. My condenser may still need to be replaced....once the car is cool though, it works good (I need to lower the fan)..with the fan on medium driving down the road, I'm about 40 at passenger vent and 44 at driver vent.

One question..If the drive side vent is 4 degrees warmer then the passenger side, does this mean I'm low on refrigerant or is this happening because of the refrigerant grabbing heat as it flows through the evaporator?

So the wife is happy at the moment, so I gues I'm happy..

I would like to thank everyone for there help troubleshooting this issue


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