Advance AC help needed

[BNaylor]

Originally Posted by greenlight99

I'm not going to say that this is the answer but on my 99 gtp with dual zone, I had cold air out of the passenger's side and none out of the driver's side. I found this http://www.clubgp.com/newforum/tm.as...059089#3213872
and decided to try it. I work at a shop and we have a professional AC machine so I was able to get a more precise reading on the amount of refrigerant I put in. Sure enough, my AC worked great after this! Both sides were blowing cold air. As to Tsb's, I havent bothered to look...but it would make sense that they would publish one.

First of all your link doesn't work and that other auto forum is not a good or credible reference on this issue as I asked of you earlier which means giving us a credible or solid reference. TSB or factory service manual specs, etc. A lot of disinformation or speculation. While it may have worked for you it may not work for others based on your circumstances and conditions or be factually correct. I disagree with your findings as a general guideline and using that as a recommendation. What are your vent temperatures, which is what really counts in the end.

With 2.25 lbs you put in 36 ounces with is the equivalent of 3 full cans of typical R134a (12 ounces).

1.88 lbs comes out to 30 ounces.

[greenlight99]

Look, my point isnt to argue with you or anything...follow this link

http://www.autoacforum.com/messagevi...threadid=10601

If not, I copied the info below:

I found this service bulletin while looking at online service manuals for my car. Apparently certain GM vehicles were undercharged when they left the factory. My Helms manual calls for a 30oz charge, but this bulletin is calling for 1.02 kg (2-1/4 lbs) of R134a.

The original posting is here: HVAC Lack of Performance. The URL uses a strange port number so you may not be able to access it through certain company proxy servers. Sorry for the bad cut/paste job...


Document ID # 655009

--------------------------------------------------------------------------------

HVAC Lack of Performance (Evacuate and Recharge the A/C System) #99-01-38-005
HVAC Lack of Performance (Evacuate and Recharge the A/C System)
1997-2000 Buick Regal

1999 - 2000 Buick Century

1997-2000 Chevrolet Monte Carlo

2000 Chevrolet Impala

1998-2000 Oldsmobile Intrigue

1998-2000 Pontiac Grand Prix

Condition
Some customers may comment on a lack of expected performance of the air conditioning system in hot humid weather.

Cause
This condition may be caused by an undercharged A/C System. This may have occurred during the vehicle assembly process.

Correction
Service correction procedure for 1997 through 1999 vehicles

Perform the Cooling Insufficient, A/C System Check found in the HVAC section of the appropriate Service Manual. If a condition is identified, make the appropriate repair. If no abnormal condition is identified, proceed to the next step.
Evacuate and recharge the A/C system with 1.02 kg (2-1/4 lbs) of R134a.
Replace the A/C evaporator label with P/N 10442041. This label will allow future service technicians to know at a glance how much refrigerant is required by the system.
Service correction procedure for 2000 model year vehicles.

Chevrolet Impala/Monte Carlo, SOP through VIN Y9133359.

Buick Regal/Century, SOP through VIN Y1101894.

Oldsmobile Intrigue, SOP through VIN YF115332

Pontiac Grand Prix, SOP through VIN YF115332

Perform the Cooling Insufficient, A/C System Check found in the HVAC section of the appropriate Service Manual. If a condition is identified, make the appropriate repair. If no abnormal condition is identified, proceed to the next step.
Evacuate and recharge the A/C system with 1.02 kg (2-1/4 lbs) of R134a.
Replace the A/C evaporator label with P/N 10442041. This label will allow future service technicians to know at a glance how much refrigerant is required by the system.
Service procedure for 2000 model year vehicles within the following VIN breakpoints

Chevrolet Impala/Monte Carlo, VINs Y9133360 through Y9206366.

Buick Regal/Century, VINs Y1101895 through Y1178929.

Oldsmobile Intrigue, VINs YF115333 through YF191330.

Pontiac Grand Prix, VINs YF115333 through YF191329


Important
This group of vehicles had the correct amount of R134a installed at time of manufacture, however, the label was incorrect.


Service procedure for 2000 model year vehicles greater than the following VINs

Chevrolet Impala/Monte Carlo with VINs greater than Y9206366.

Buick Regal/Century with VINs greater than Y1178929.

Oldsmobile Intrigue with VINs greater than YF191330.

Pontiac Grand Prix with VINs greater than YF191329.


Important
These vehicles were produced with the correct amount of R134a and the correct Label.


Inspect/test the A/C system for signs of leaks both visually and with the A/C leak tester used in your service facility.
If a leak is found, perform the recommended repair as outlined in the appropriate Service Manual for the vehicle being serviced.
If no leaks are found, perform the Cooling Insufficient, A/C System Check found in the HVAC sub-section of the appropriate Service Manual. If a condition is identified, make the appropriate repair. If no abnormal condition is identified, the system is operating per design specifications.
Parts Information
Part Name Part Number
Label, 10442041

Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation Description Labor Time
D4702 HVAC System Check 0.6 hr*

This is a unique Labor Operation Number for use only with this bulletin. This number will not be published in the Labor Time Guide.

*The 0.6 hr includes the time required to install the new label. If an evacuate and recharge was required, add 0.9 hr to the base time for Evacuating and Recharging the HVAC system.

Sorry about the length of the post but I guess I need to in order to have "a good source."

[BNaylor]

Originally Posted by greenlight99

Look, my point isnt to argue with you or anything...follow this link

http://www.autoacforum.com/messagevi...threadid=10601

If not, I copied the info below:

I found this service bulletin while looking at online service manuals for my car. Apparently certain GM vehicles were undercharged when they left the factory. My Helms manual calls for a 30oz charge, but this bulletin is calling for 1.02 kg (2-1/4 lbs) of R134a.

The point I am making is getting proper and relevant info posted in this forum and relevant to a member's issue which in this case is obviously a leak or system malfunction. Not a charge issue. That is why I am a Moderator and responsible for reviewing tech content. The TSB may be relevant to some but not to all of us.

For a change IMO your Helm's service manual is basically correct as a general guideline. The problem with TSBs which is why I asked to see it is they are are written for GM professional/auto techs and not the general public although we can reference them since they are posted all over the Internet. We have a tendency to misinterpret them or abuse them. They apply to certain conditions if the owner experiences that respective issue and the other parameters stated within the TSB. Note that the conditions are for high humidity areas/conditions and GM vehicles falling in those year groups and VIN range specified only. I have the 1.88 lb label on all of mine and the charge works out just fine based on my location, temperature and humidity. Plus I do not see any references or subsequent corrections to the GM FSM (factory service manual) where it mentions the 2 1/4 lb refrigerant charge versus the 1.88 lb charge.

[greenlight99]

^^^ I fully understand your point with misinterpretation of information...for that I stand corrected. However, whether you believe this information to be a myth or not, it definitely fixed my problem which seemed very similar to umina's. So, with that being said, you can take the information or leave it. (Even though that does sound like a "my best guess" statement.) Good luck on fixing the problem!

Brian

[BNaylor]

Originally Posted by greenlight99

^^^ I fully understand your point with misinterpretation of information...for that I stand corrected. However, whether you believe this information to be a myth or not, it definitely fixed my problem which seemed very similar to umina's. So, with that being said, you can take the information or leave it. (Even though that does sound like a "my best guess" statement.) Good luck on fixing the problem!

Brian

Your point is well taken and I acknowledged that it appeared to resolve your issue but just may not be relevant to all situations posted. The info may help someone else with a similar issue so it appears to be beneficial. However as I pointed out something is not right about it and from my experiences best not to take the GM TSBs as the gospel. Just as an example I'm not about to go out and recharge to 2 1/4 lbs when all my A/C systems works super with frigid air out every vent register, acceptable temperature balance between driver and passenger sides, and vent temperature below 40 degrees. As a matter of fact it just hit 100 degrees in my neck of the woods but I have very low humidity. We have to use our common sense.

[umina]

Well thanks for all the great information. Since i've put 5 cans in the car since i got it, i'm pretty sure if the system were tight it would have gotten cold so its leaking somewhere. I checked around town and everyone wants 80 to 90 for a AC diagnostic. The GM dealer wants 91 bucks for it, and their test includes an electronics scan with the Tech 2 scanner, as well as a leak down pressure test and evacuation of the system. Soon as i get paid again, i'll most likely take it to them, its worth $100 to find out whats wrong. Now whether or not i pay them to fix it is something else entirely. I'll post back with results after the visit.

[umina]

OK, so i just came back from my appt. at the dealer. They said my compressor is shot and is unable to maintain pressure on the high side. I just want to verify what they told me here though:

1. The system has a high pressure relief valve which is why even though i've dumped 5 cans of R134a in it since Jan. it is not overcharged, but charged correctly. They pulled out 1.77 lbs and the system holds 1.8. Is there really a high pressure relief valve in the system that just blew out the extra i was putting in?

2. In the diagnostic, they said the compressor clutch runs constantly when AC is on, but isn't that a characteristic of the V5 compressor, that it is always engaged rather than cycling on and off?

3. They said that both tubs that go the compressor are hot, and one should be cold, they're probably right here though.

So they want $1200 to replace the compressor, accumulator and orifice tube. I said no thanks and walked. How hard is the compressor to replace once i evacuate the system (they recharged it when done)? I'm fairly mechanically inclined and grew up working on cars, never done a AC compressor though....

[tblake]

They recharged it? WTF? I thought you paid for an evacuation?

To answer your question.... Comressor r&r isnt so hard. Need the system evacuated, two bolts (I believe) hold the compressor to the block, and the one bolt that connects the AC lines to the compressor. Make sure you replace the little seals from the lines. Also when you have your compressor out, get some sort of measuring container to dump the pag oil into. You'll need to add this exact same amout when you go to install your new compressor. Like the dealer, replace the Orifice tube as it probably is full of metal shavings. Then take the vehicle to have a vacuum pulled on the system and recharged.

Good luck finding a decent price on a compressor. I think the v5's may be sort of expensive. (well, all of them are)

[BNaylor]

Yeah something doesn't sound right. There is a high pressure relief valve on the back of the Delco/Harrison V5 compressor but if you ran dye through the system then it should have been detected. And based on the latest readings with high side pressure the high side pressure was no wheres near the pop off point.

What are the current low and high side readings and is it no longer leaking? Depending on the readings you may just have a bad variable control valve which is what makes the V5 a variable displacement compressor and no it does not cycle on and off. It runs all the time and varies stroke based on load. The valve runs around $70 and you can replace it without replacing the complete compressor. Just held into the side of the compressor with a c-clip. Located on the side of the compressor radiator side and underneath. The system does need to be recovered and evacuated before replacing the variable control valve and then properly recharged after a vacuum.

I can post a pic of the variable control valve once I find it. I replaced one in the recent past.

[HotZ28]

Hopefully, Bob is right about the “variable control valve” being the problem. If the compressor is actually “shot” as the dealer claimed, you will find debris in the expansion valve (orifice screen). If so, you will need to do a complete system flush to remove debris from the evaporator, condenser and high/low side lines. Even then, there is no guarantee that all the trash will be flushed out. Anytime the system is opened for maintenance, such as a compressor replacement, you will need to replace the accumulator in order to preserve the warranty on the compressor.

It is hard for me to believe that you have added five 12oz cans of 134a and the dealer only recovered 1.77 lbs. You must have a leak somewhere! If the high side pressure relief opened, you would here a sound like a rifle shot and the pressure would relieve rapidly. In addition, it is highly unlikely that it would only bleed to near the system capacity. Most aftermarket 12 oz refrigerant cans contain about 1-2 oz of oil. If you have the system saturated with oil, even a new compressor will not function properly. If this is the case, a system flush is mandatory!

BTW, the most difficult leak to detect or find, is usually the evaporator core.

[BNaylor]

Originally Posted by HotZ28

Hopefully, Bob is right about the “variable control valve” being the problem.

Yeah hopefully Bo because it will save him an arm and leg, $$$. But the symptoms are unique so it is hard to rule out the compressor but that is why we need to know the latest low and high side pressures. Here is that article I provided to you when I asked for that second opinion. Yes, we Mods consult and help each other out too.

Click here

Plus since the valve aka RCV (refrigerant control valve) has at least 4 o-rings seals that could be the source of a leak but based on it's location you would see any detection dye.

Also, as a fail safe when the high side pressure gets way out of specs the PCM module will disable the compressor clutch via sensing at the pressure switch so that would probably occur way before the relief valve at the compressor pops off. So the story from the shop doesn't sound right.

[brcidd]

I know/knew (engineering-wise) those compressors inside and out-- a HPRV release would put a cloud of refrigernat under the hood so bad you would be stopping driving to see what happened-- plus the noise it creates---plus the entire engine bay behind the compressor would be dripping with green oil--very, very discernable-- your technician should know this--- you most likely have a leak--the compressor may have a control valve problem-- but it is rare-- I have replaced maybe 3 in ten years---those pumps will do great if they have enough refrigerant to pump--I reseal them- install all new cylinder and front head o-ring- and they work great......

[BNaylor]

Originally Posted by brcidd

-the compressor may have a control valve problem-- but it is rare-- I have replaced maybe 3 in ten years---those pumps will do great if they have enough refrigerant to pump--I reseal them- install all new cylinder and front head o-ring- and they work great......

Ah see interesting point. Even you admit the variable control valve (RCV) does go bad. Easy extrapolation if you do the math. Just think of all the V5 compressors that were replaced needlessly when it was a simple replaceable part that just about anyone can do DIY without removing and replacing the compressor or wasting time and money.

I was just speculating that it could be a cause but as I pointed out there are specific and unique symptoms. Most notable when running the A/C manifold gauges the low side pressure will be high and the high side pressure will be low in most cases. What this equates to in real world operation is possible cooling at higher speeds other than idle and poor cooling at idle. Or proper refrigerant charge to include PAG oil, cooling feels satisfactory at first start up or when the ambient temperatures are low but as it heats up cooling diminishes. When gauges are reconnected both low and high pressures are still abnormal even though high pressure may come up some but to the low end of what should be normal based on the humidity and ambient temperature. Also, following he A B C D diagnostics charts the troubleshooting will take you to the compressor checks using chart B, insist the compressor is bad or constantly point to a low charge which puts you in a circle.

There is no doubt the Delco/Harrison V5 compressor is very reliable but it is subject to problems just like anything else including poor maintenance of the complete A/C system. On V5 compressor failures I'm used to the more catastrophic ones where the compressor seizes up or the clutch coil goes bad.

While on the subject of accumulators it should be replaced every 5 years regardless of whether a compressor is replaced. Also, when you replace it take proper note of PAG oil content and disposition since it is key to system PAG oil capacity. We use PAG Oil 150.

[umina]

So basically what the dealer told me about the pressure relief valve was bogus, i wonder if they even looked at the car to begin with. I looked again under the hood and there is no UV dye to be found suggesting a leak. My compressor seems to be making more noise now though then it did a month ago, maybe its shot after all. Is it possible that i could have the symptoms i'm having caused by a faulty Variable control valve?

I'm going to send a pleasant (or not so) note to the service manager at the dealer. They should know from experience that the V5 compressor is supposed to stay engaged all the time rather than cycle, and that relief valve wouldn't have popped with my low pressure readings. I can get a compressor kit off ebay that includes new V5 compressor, orifice tube and dryer/accumulator for $250 shipped. I just hate to drop that kinda money on it, plus evacuate and refill the system and not have it fix the problem.

[tblake]

250 for all those parts is CHEAP! and almost makes me wonder....

Are they genuine AC Delco's?

They are probably all the compressers that were replaced due to a faulty variable controll valve. The sell bought a ton of "bad" compressors, replaced the VCV's and now is selling them.

Never know????