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2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure


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mmichaels1970
User

Jul 7, 2014, 12:40 AM

Post #1 of 22 (3432 views)
2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Hi all,

I'm trying to figure out why my A/C blows warm air. I made sure my refrigerant was charged. The clutch is engaged and seems to be spinning well. I can hear noise when turning on A/C which I'd think means the compressor is operating. However, the cooling fans aren't activated when the A/C is turned on. The high and low pressure is the same while idling...35 psi at 75F ambient temp which is probably very bad news.

I tested the fans by connecting jumper wires and they did operate at normal speed. After jumping them, I plugged them back in and they kicked into high for a few seconds before completely stopping. I removed the relay and plugged it back in and the fans began to spin for a few seconds at "normal" speed before stopping after a few seconds. However, I wasn't able to duplicate this by trying again.

I tried swapping relays from known good components and it appears all relays are working properly.

So the fan motors appear to be ok. Relay seems ok. The clutch is engaged and spinning. The refrigerant seems to not have a leak. Any guess as to what I should check from here?

Do the equal high and low pressures indicate a failed compressor? Or are there any other components I can check before such a radical move? Is the lack of a good compressor causing the fans to fail, or is the lack of fans causing the compressor to not cool?


Discretesignals
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Jul 7, 2014, 12:49 AM

Post #2 of 22 (3427 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

If you have a proper charge, the clutch is engaged, and your gauges are hooked up and working correctly, you have a faulty compressor. It is also possible to have a completely clogged line, but that is rare.

35 psi on both sides is pretty low for even a static charge, you sure your gauges are working and you have the correct charge?

The computer monitors the pressure sensor and uses that reading to determine when the fans should be turned on. Since there isn't no pressure rise on the high side, fans won't come on.

If and when you do remove the compressor, be sure to inspect the system for metal or contamination. If there is contamination, you'll need to flush the system out and replace the condenser, txv(s), and drier.

If it has rear air, you'll need to replace the rear txv valve and flush those lines and evaporator also.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Jul 7, 2014, 12:57 AM)


mmichaels1970
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Jul 7, 2014, 1:16 AM

Post #3 of 22 (3413 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Thanks for your quick reply! I agree that the compressor is probably bad. I was just hoping for better alternative news.

I confirmed 35PSI with two different gauges. At 75F ambient, my chart said that this was an ok charge. However, I did lift it to 40 last night just in hopes that the chart might be a little off.

I think pulling the compressor is probably beyond my limited capability. If it weren't my primary vehicle, I might give it a try.

For now, we'll just have to live without AC and try to squirrel away a bit of $ each month to possibly get it fixed next summer.

Thanks again!


Tom Greenleaf
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Jul 7, 2014, 1:26 AM

Post #4 of 22 (3410 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

! 35PSI at 75F something is totally wrong right there. System is OUT of gas or gauges aren't even picking up static pressures at that pressure represent vehicle and all A/C components are totally @ 35F near exactly! It can't have a real refrigerant gas in it and that pressure for real,


T



mmichaels1970
User

Jul 7, 2014, 3:17 AM

Post #5 of 22 (3394 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In


In Reply To
! 35PSI at 75F something is totally wrong right there.


The gauges I'm using say that 35PSI on the low side is right where I want to be.

I did bump it up to 40 last night just to be sure.

My gauges came with a chart that looks like this:

http://acprocold.com/wp-content/uploads/2011/11/Temp-pressure-chart-33776F1.jpg

Where 75F specifies 35-45 PSI for R134A.

I'd love to hear that I just need to bump the pressure up further to get it working, but anything over 45 on my gauges shows "yellow zone" or "red zone".


Tom Greenleaf
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Jul 7, 2014, 4:03 AM

Post #6 of 22 (3388 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Equal high and low pressures with compressor engaged there's something totally wrong. That just sound like a static pressure of WAY too low on refrigerant.
Check pressure without it even running the engine then what is it? How do you even think there's a charge in it without charging from empty you can't know but could know it's operating within norms.


Yes you could have a low pressure of that but not both when running so it appears the compressor is just flailing in the breeze as for pumping anything.


Make sure you hook ups to gauges and knobs (or however operated) are in correct position or you'll read all kinds of wrong info.


In short if 35PSI on both sides is correct there isn't enough refrigerant in it to do anything not even give you a pressure/temp static pressure that's credible. Check how you are hooked up and really should do one last try at a vacuum and charge to spec and see what you get if everything else checks,


T



mmichaels1970
User

Jul 7, 2014, 5:36 AM

Post #7 of 22 (3377 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Thanks again for the quick reply!

After reading your response, I ran home really quick to check it out. I added a bit more refrigerant to get me to 45psi on the low side. We are about 78F ambient here so 45psi matches ok with the chart recommendations.

With car off, I'm getting 45 low and 45 high psi. With car in idle and AC on I'm still getting 45/45. When I add some RPM's (2000-2500) I do see the low end dropping to about 30psi and the high side rising to about 50-55 psi. So the needles are definitely going in opposite directions when RPM's are applied, but the high side is obviously nowhere near where it needs to be.

I will take your advice and pick up a vacuum pump and compressor to do a vacuum (haven't done one yet) and then recharge to spec. It's game over for the season if I have to replace the compressor. So I will try out any other recommendations I get to see if I can get the compressor to kick over.

I really appreciate the suggestions!


Tom Greenleaf
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Jul 7, 2014, 6:06 AM

Post #8 of 22 (3367 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

OK - I'll post the chart below. Applies to static pressure at what temp or with infrared in a working system if you know the temp you know what pressure is right there - IF THERE'S EVEN CLOSE TO ADEQUATE REFRIGERANT!




So if you see with engine off it just like taking tire pressure except refrigerants are totally temp sensitive and pressures at which times they are liquid or gaseous/vapor.


When pressure is lower just sitting there than on that chart you just have a smidge of refrigerant in system so nothing is going to happen. Bad news is oils used in A/C are carried by a system with enough to do its magic of evaporating a liquid then under pressure at the evaporator which should return vapor with some oil for compressor which it can't and burns out in no time and that probably happened already sorry to say. Worse is if (likely) it throws debris and wipes out item downstream. Hope I'm wrong but think this system is trashed now.


One last test for this post. Try (engine off/key off) if you can turn by hand with belt on the center of compressor. If you can't it's locked up now and really by rights be making wild noises. If that somehow turns easy by hand (would be a never for me) the shaft isn't even doing anything and can't think of how that could happen without it coming right off the car?


Don't just go aimlessly adding refrigerant! When pressure are that messed up about the only wild maybe for this to still work which would be a miracle would be evac (count how many oz's come out) and charge exact oz's into a well held vacuum.


Getting old. A total vacuum at sea level is 29.92Hg. Ok. That sounds ducky if it hold but remember it's only sealing out atmospheric pressure not the pressures of a working system inside it. Atmosphere is about 14.7PSI (might be off on that but close enough) so not a sure bet it will hold pressure.


One more last (guess I lied) check your gauges on something else either that works or just pressure from a source. You are posting both high and low pressures to guessing you are using a manifold gauge set - right? If not working them properly you might be reading just the can's pressure if doing this that way and why that low is still in question unless you keep it refrigerated?


This is NOT just add and go DIY friendly stuff when all is even right and a system just a tad low. The tuition for mistakes is nasty on the wallet too,


T



mmichaels1970
User

Jul 7, 2014, 8:21 AM

Post #9 of 22 (3353 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Ok. Here are the gauges I'm using:


And here is the chart I'm using. Maybe I'm not talking about PSI correctly, but this chart corresponds with the gauge:



I'm done with adding refrigerant for now. I'll take a closer look a bit later on today and see what I can come up with. I've done a bit of repair work, but I admit I'm not at all qualified with A/C.


Tom Greenleaf
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Jul 7, 2014, 9:11 AM

Post #10 of 22 (3347 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

That chart is just low pressure OPERATING pressure and so incomplete it's useless sorry to say. RPMs not shown, vent temps, ambient temp matters, fan speed for interior and tons more.


You really can't charge or boost without a ton of knowing what to expect by type of vehicle and all conditions. Run car for a boost that just is below par perhaps quite a while and if good can boost up to close with all observations in the #s you'll find.


Thanks for the effort for taking the pic of gauges. I can't read them in my view so take your word what they are telling you. Not sure it matters but do you shut those off to read vehicle pressures by turning the whole gauge head or what? I'm more used to nasty expensive stuff and older than dirt but still right on the money.


With whatever source you are using, little cans or a 30 lb bottle you should be able to plain read the pressure of the source with yellow hose. Is that possible on that set? The side fake ports may not be a seal but just a parking place for hoses when not in use. Last bit of hose should have an in line shut off and you really do have to think of what pressures are from where with what is opened and what closed.


They key question I have a problem with is the equal pressures and how low they read. It's just not consistent with even a sealed broken system so one of us is missing something or gauges are screwing you up????


Sorry for the novel - have to rethink doing all this crap with the assorted stuff I still have but haven't needed squat for just my own in some time now. Try if you dare reading on a car/vehicle that works properly to test out those gauges,


T



mmichaels1970
User

Jul 7, 2014, 10:35 AM

Post #11 of 22 (3333 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Yes. It sounds like the gauges I'm using are a bit lower tech than those you probably use. They ran me about $50 at the parts store. I guess they don't show anything but operating pressure.

On the gauges, there is a little quick connect hose that has shutoff valves on the red and the blue. The blue dial also turns if you want to use the yellow hose to add refrigerant. The yellow hose has a twist valve that is designed to penetrate the can of coolant attached (which I'm not using).

I added the refrigerant using the "little can" of ac/pro:



Which has a gauge that looks like this:



The reading on the ac/pro gauge matches the reading I'm getting from my blue hose when I connect it to the low end.

So I probably don't have sophisticated enough equipment to diagnose other pressure readings other than those that these gauges are handing me now. I'm not really qualified enough to know that there are any other readings to report other than the ones I'm seeing.

Thank you again for all of your help. Whether I get this repaired or not, I'm certainly learning a lot here.


Hammer Time
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Jul 7, 2014, 11:30 AM

Post #12 of 22 (3329 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

There is a name for that setup. It's commonly called a "death kit".



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mmichaels1970
User

Jul 7, 2014, 12:51 PM

Post #13 of 22 (3320 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Thanks for the reply. So is my "death kit" inadequate in determining if there is anything I can do before giving in and concluding that this is a bad compressor? Of course I can save up a bit and get it to the shop. Just thought there may be some alternatives to look at before giving in.


Hammer Time
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Jul 7, 2014, 12:55 PM

Post #14 of 22 (3317 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

That little gauge certainly isn't going to help you at all but the gauges you showed earlier will.

Exactly how much refrigerant is in the system and what are the high and low pressures at idle?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mmichaels1970
User

Jul 7, 2014, 1:01 PM

Post #15 of 22 (3313 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Ok. Cool. I thought my manifold gauges were the "death kit". I agree that the recharge kit gauge won't tell me much. My high and low are both at 45psi with engine off and at idle.

At 2000-2500 rpm, low drops to about 30 and high goes to 50-55ish. Obviously inadequate pressure on the high end to kick out cool air. So I'm not sure if that's game over or if I should attempt a vacuum and recharge, or something else before throwing in the towel.


Hammer Time
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Jul 7, 2014, 1:03 PM

Post #16 of 22 (3311 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

How much refrigerant is in this thing?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mmichaels1970
User

Jul 7, 2014, 1:11 PM

Post #17 of 22 (3307 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

How do I measure that? I only know that when I first popped the hood and checked the low it read about 35 at idle. I added some refrigerant to get it to 45 which was at the upper limit for my ambient temperature.

I hadn't had the system discharged or vacuumed as I'd hoped the issue was simply the need to squirt a bit of death kit into the system.

By the way, thanks for your responses and advice!


Hammer Time
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Jul 7, 2014, 1:14 PM

Post #18 of 22 (3305 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

There is no way to know how much refrigerant is in the system until you remove it all, vacuum the system and charge it with the exact specified weight. Until you do that, all these pressures mean nothing at all.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mmichaels1970
User

Jul 7, 2014, 1:36 PM

Post #19 of 22 (3296 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Ok. Your post is kind of what I'd hoped to hear. So it's possible my compressor may still have life if I get my refrigerant removed and get it vacuumed. I assume if I get the refridge removed I can do the vacuum and charge on my own right?


Tom Greenleaf
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Jul 7, 2014, 1:42 PM

Post #20 of 22 (3293 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Thanks Hammer for jumping in. We need to get some real info on this thing. Two close to "death kit" devices being used and #s PLAIN DON'T WORK! YOU CAN'T HAVE 45PSI on BOTH SIDES RUNNING OR NOT AND HAVE REFRIGERANT IN IT WORTH A DAMN at said ambient temps. It's empty for all intents and purposes.


At this point I suggest the best thing is bail out on this and send it out. $50 gauges! I doubt I can get one hose for a S/O gauge set! That and the death kit can and gauge. Nothing says on that junk to purge air out hoses even. This is a mess and unknown damage IMO already either before or from messing with it unfortunately.


Virtually all set ups quit with low pressures for a reason and some too late to save a compressor and the hell that comes from burning one up,


T



Hammer Time
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Jul 7, 2014, 1:42 PM

Post #21 of 22 (3293 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

This system requires 1.68 lbs or as close that that as you can get.

That is 26.8 ounces so 27 ounces is your target. That's what is tough bout using cans to charge. You are better off to just pay a shop to do the whole thing. You should be able to get it evacuated and recharged for around $100.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



mmichaels1970
User

Jul 7, 2014, 1:46 PM

Post #22 of 22 (3286 views)
Re: 2007 Uplander - No AC, Clutch Engaged, No fans, equal high and low pressure Sign In

Ok. I'll call around tomorrow to see if I can get an evac and recharge done. $100 is more than reasonable. I'm still afraid my compressor is shot, but $100ish is worth it to find out.

Thanks again and I'll post back the results!






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