Engine Size: 5.7
Refrigerant Type: R134
Country of Origin: United States
I have been having a/c issues since April. It started with a leaking manifold hose but since then I replaced EVERYTHING except the front evaporator. I mean everything some parts were replaced multiple times but thats a whole other story. I ordered guages which finally arrived so I figured let me see whats going on. One thing I noticed on the highway this morning my center vent temps fluctuate big times anywhere from 38-45 degrees. Doesnt matter speed thou it seems to blow cooler when im going under 40mph. In the past few weeks it would stay around 38-40 no matter the speed on the highway until I either hit traffic or got off the highway.
Started the truck, outside temp is 83 degrees with 70% humidity.
5 minutes at idle:
low 50, high 210 with 66.5 center vent temp.
10 minutes idle
low 50, high 230 with 63 center vent temp.
5 minutes @ 1500RPM
low 40, high 360 with 58 center vent temp.
7 minutes @ 1500RPM
low 33, high 265 with 53.5 center vent temp.
10 minutes @ 1500RPM
low 32, high 260 with 52.8 center vent temp.
12 minutes @ 1500RPM
low 35, high 320 with 54.5 center vent temp
I recently replaced the fan clutch with a sever duty hayden, I added both a 9 and 14" electric fans on the condenser. But im still not happy. Any suggestions.
2000 Cadillac Escalade w/rear air
Important question: Where were the parts sourced from?
Sounds like an airflow issue, since the vehicle seems to cool well while moving. What happens to the vent temps and pressures if you water down the condenser?
When the system was opened for subsequent parts replacement, was more oil added? How long was the system vacuumed?
You have air in the lines that's a big reason why performance is poor and pressure high. Evacuate and charge properly. Also fan clutch seems to be weak. Stay away from variable orifices and HC refrigerant.
What makes you state to stay away from variable orifices and HC freon? ( This is all new to me)
2000 Cadillac Escalade w/rear air
And as far as the fan clutch I recently replaced my stock unit with a new severe duty unit from Hayden, turns out it was bad out of the box. Upon accelerating it would immediately slow down nevermind temp went up about 10 degrees. So I replaced it with a new one which seams to be fine. But maybe im wrong. Im no expert but if I had to guess I would say the clutch is fine rather the condenser ( this is the 3rd new one in 3 months) is weak. Again I dont really know. I appreciate any help!
2000 Cadillac Escalade w/rear air
Edited: Thu August 04, 2011 at 9:38 PM by Stresst
First, the system was designed to use R-134a. Second, there is no reason to use a HC refrigerant when R-134a is legal, plentiful, and relatively inexpensive. Third, HC refrigerants can go boom.
What kind of HC refrigerant were you considering anyway? They all have different characteristics. I see no reason why the system needs to be re-engineered.
It sounds like your system is just one big hacked up mess. Is the condenser plumbed properly? Where was the OT installed?
Best plan of action would be as follows:
- Replace the compressor
- Replace the condenser
- Replace the accumulator
- Replace the OT (no variable orifice)
- Replace the rear TXV
- Replace any hoses with mufflers
- Thoroughly flush and dry the front evaporator
- Thoroughly flush and dry the rear evaporator
- Thoroughly flush and dry any remaining lines
- Replace o-rings at every fitting
- Add 11 oz of PAG 46 oil
- Pull a deep vacuum on the system for several hours or at least down to 600-700 microns. The longer the better. This an extremely important step that appears to have been skipped throughout.
- Charge system with 48 oz R-134a
All parts above should be brand new OEM parts, or parts from ACKits.com, otherwise you'll end up spinning your wheels. If you don't start with an operating room clean system, you're going to end up with repeat failures.
I recently found out the condenser was plumbed incorrectly so we got that staightened out. The orifice is near the Y-pipe where it belongs. Like I said in my original post EVERYTHING is new except the front evaporator. I was thinking of Enviro-safe Advanced/Industrial R134 replacement. I understand about trying to redesigning the system but when your in for over 3K and the a/c is less then desireable im looking outside the box.
Im curious as to where you came up with 48 oz of R134?? Capacity I think maybe an issue........Alldata & Chilton both state 2.75lbs, while Napa and tech choice parts list 4lbs, I seen another chart that says 3.5lbs so I really dont know what is the actual capacity.
2000 Cadillac Escalade w/rear air
Edited: Fri August 05, 2011 at 1:57 AM by Stresst
I've read your threads & posts on the different AC / truck forums about your truck and I know you purchased a set of gauges to do some testing.
You seem to be chasing your tail as you have mentioned several times how much $$ you have put into getting cold air but also acknowledge that the system has been opened, parts replaced, oil added or not added and then no vacuum drawn (on a system with air in it?) before charging again ... you can't do this (pay someone to ) and expect results.
You have mentioned what a few shops have done or attempted to do and you don't seem happy.
I would cut my losses and start at the beginning as mentioned above.
Get educated on auto AC systems, get the basic tools needed (vac pump and gauges, let shop recover and flush) and do it yourself.
1st you need this:
Read and reread then read again first 5 chapters.
Perform the tests as described in the manual. (gauges)
Then I'd follow everyone's advice on how to:
1. properly evacuate
2. breakdown and flush
3. replace components
4. reassemble and add oil
5. pressure test
6. vacuum and test
7. ... and finally charge.
1999 GMC K1500 Suburban SLT
5.7L Vortec with C69 Rear Aux Opt,
Part of the problem seems to be repeat failures, and that's easy to see why with improper or no existent flushing procedures, lack of pulling a vacuum, which increases the probability of moisture in the system, and more oil than Saudi Arabia. The system needs to be operating room clean, with all correct parts, brand new.
Are you sure you got the right compressor in this thing? In 2000, GM used 3 different compressors for this platform:
- Delphi HU6: 6 cylinder, used only for the pickups.
- Denso 10S17: 10 cylinder, front air only (GM RPO C60)
- Denso 10S20: 10 cylinder, front and rear air (GM RPO C69)
The fact that you mentioned you had to bad Delphi units leads me to believe you have the wrong compressor for rear air; you need the Denso 10S20 which has quite a bit more displacement than the Delphi HU6. And of course, different displacement means different refrigerant and oil levels.
What orifice tube are you using? A lot of folks automatically dump the GM white 0.072", but I think this vehicle needs the GM yellow 0.062" instead.
Jase007 is also giving you very good advice... you're not getting this stuff done right and spending a lot money needlessly. Do it right, and you'll only be doing it once.
My suggestion is to purchase the Alldata or Mitchell subscription for this vehicle. I doubt anyone is going to come up with a sentence or two to fix your issue. You have a thread here and another Bulletin board. Bottom line is you need to get back to the OEM setup. Proper oil amount, refrigerant amount and OT. if you willing to do that we can provide some guidance. If not, I can't come up with the magic answer. Scan tool may be needed to read the codes you might be getting also.
What help has your supplier provided with these issues?
(cue boxing announcer voice)
Aaaaand we have a contender from NY! So far the oil overcharge record is about 19 ounces in a dual evaporator suburban, but it looks like Angelo may be gaining on Tom!
Pull those evaporators & drain them! Drain that condensor! Drill a hole in the accumulator & fill those measuring cups! Angelo that title may be yours!
(sarcasm ends here)
You need to flush that system. Every component individually. Both evaporators, the condensor & all of the hard lines need to be flushed back to bare metal. Zero oil. None. Nada. Zip. Clean enough to make paint stick.
Throw the accumulator in the trash. Blow all of the oil you possibly can out of the flexible lines. Drain the compressor.
evacuate the system to less than 1000 microns, or it will never cool right.
Hecat's tech paper should cover these questions. As for oil. Much debated question. I go 80 percent compressor 20 percent accumulator or evap.
Flushing is really just part of a quality repair. There are no shortcuts, every component gets flushed by itself. It is not possible to flush through an expansion device, so the rear TXV needs to come out. Same for the front evaporator. The only way to get the correct oil charge in is to get all of the old oil out first.
Once the system is clean and dry, the new oil charge is added to the compressor and what does not fit there can be dumped into the new accumulator. Once the refrigerant begins to circulate the oil spreads around immediately.
A good vacuum is necessary to remove all of the air from the system. Less than 1000 microns, and as low as 400 microns is an excellent vacuum level for an MVAC system.
Unfortunately a lot of otherwise decent mechanics think A/C is just something to throw parts at, and do not understand how much trouble too much oil can cause. An extra four ounces of oil is like a quart overfill on a transmission. They would not think of filling a cold power steering system right to the brim, but 3x the oil charge in an A/C system does not sound like a big deal to them.
Perhaps if you sit down and carefully explain the problem and what needs to be done to correct it to your fleet service company they can help you resolve it. Having a tech on staff that knows what he is doing with A/C can make a shop a lot of money. A "teachable moment" as they say, that you may be able to make work for both of you.
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
Edited: Sat August 06, 2011 at 5:05 PM by bohica2xo
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