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Expected pressures for a couple vehicles

cmeseadoin on Sun May 18, 2008 11:11 AM User is offline

Year: 1995
Make: Chevrolet
Model: S-10 ZR2
Engine Size: 4.3L
Refrigerant Type: R134A

Hey again guys,

Hope all is well with everyone. I have a couple more questions regarding a couple other vehicle.

Could anyone tell me what static pressures as well as operating pressures (High and Low side) at a certain RPM and amb. to expect for a 1995 Chevrolet S10 ZR2 pickup with the 4.3L R134A system? I am troubleshooting a friend of mine's S10 and the compressor won't kick on. It is being brought to me today and I have to start at square one with troubleshooting. Mechanical issue or refrig. charge issue.......

Also, I have to service my mother's car which is a 2000 Subaru Legacy Outback wagon with the 2.5L 4-cyl R134A system. I need to know operating pressures on that car as far as HIGH and LOW expected pressures at a said RPM. (2K rpm is the basis for comparison among most, right?)

If someone could help me with this, I would be most appreciative. Is there somewhere I can go, some web, that has goobs of this information? I appreciate it guys! :-)

Chris

TRB on Sun May 18, 2008 12:22 PM User is offlineView users profile

ALLData has this information for a small fee per vehicle. Library may also still have Chiltons manuals. I pay one online resource $ 179.00 a month for vehicle data.

AllData link

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Sun May 18, 2008 at 4:22 PM by TRB

bohica2xo on Sun May 18, 2008 12:32 PM User is offline

On the Subaru, you will see a wide pressure range depending on ambient temperature. It is a small system with a Zexel DKV (vane type) compressor. Oil quantity is important. There are two fans, each with it's own relay - make sure they both work. The HPCO opens about 455 psi, and closes again at 399 psi. The low side should be between 27 & 37 psi.

Refrigerant quantity 21 - 25 ounces. Oil quantity 4.0 ounces of ZXL200PG

Subarus tend to be bug eaters. Clean the condensor well. Also, replace the cabin air filter if so equipped. Most Outbacks have them, and they rarely get changed once the dealer quits doing the service. They can restrict evaporator airflow if filthy...
.

The S10. You test @ 1500 engine RPM, windows & doors closed. Cabin fan on highest setting, recirculate air.

The chart for the S10 is referenced to ambient temps. For 80f @ 60% humidity, you should get the following result after 4 minutes of operation as described above:
Low side 26 psi, High side 299 psi, center vent 45f.

At 90f... 35 / 385 psi, 56f vents.

As for the troubleshooting, I show two different wiring diagrams for that vehicle - one with a control module mounted in the r/h side of the engine bay, and one without said module... You may have to wait for GM tech on this one.

B.

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"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.

cmeseadoin on Sun May 18, 2008 4:05 PM User is offline

TRB: $179.00 a month? I'm sure A/C just might be your profession, but for that price.. no thanks. I do this on the side and help people with A/C when I can. I have a professional job outside of automotive. I am very happy with this forum as most members are very helpful because they have valuable experience from working with various systems. That is why I am here as are many others. In return, when I can assist someone somewhere with something, I will do so. I'll charge the thing slowly using experience, pressures and vent temps as my comparison before paying that.

Bohica: Thank YOU so much for the information! I have an o-ring to replace in the Subaru as I know there is a leak and I know where it is. I needed the pressures so I can double check once I recharge to spec so thanks for that!! The S10, looked at it just now. There is no refrigerant in it....need to evac, vacuum and see if it holds vacuum. Maybe due to attrition over years. We'll see. I wanted pressures for a comparison gauge as well when I get it recharged.

Here is one more question: I cannot find anywhere under the hood of the S10 what the oem charge capacity in ounces/lbs or kg.? Any ideas? Again, thanks so much, you've always been so helpful! :-)

Chris

TRB on Sun May 18, 2008 4:29 PM User is offlineView users profile

I was not suggesting you needed to purchase the same program we use. But the Alldata option is a good deal per vehicle. Remember programs like Mitchell and Alldata have copyright issues. So I can't just cut and paste data. But you can copy this data from some library's!

S10 refrigerant capacity is 32 ounces.

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

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Sun May 18, 2008 at 4:54 PM by TRB

bohica2xo on Sun May 18, 2008 4:51 PM User is offline

You are welcome.

Tim is on the money with the AllData subscription - especially for vehicles with electrical issues, and complicated systems. If you work on your own car more than once, the subscription is cheap, and can save you hours.

If the Subaru has been leaking oil, I would consider flushing to bare metal for a proper oil refill. 4 ounces total does not leave a lot of wiggle room for guessing at the volume to replace.

B.

-------------------------
"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.

cmeseadoin on Mon May 19, 2008 9:43 AM User is offline

Ok, so I pulled a vacuum on the S10 last night to see if the system would hold vacuum. I was able to pull down to about 29.5 IN HG. I ran vacuum for about 45 minutes then locked the vacuum in the system and came back a couple hours later. I had lost about 1.5 IN HG. The temperature changed here yesterday with a system coming through and the truck is outside. I know that as the temp changes etc. vacuum numbers will probably change. I decided to leave my manifold gauges on it over-night with the vacuum in the system and just close the hood. Came out this morning and it was 47 degrees. All vacuum gone from system. I am trying to determine what this means. I am wondering what should be expected with vacuum loss and the thing that could be going on too is that all my little rubber seals in my manifold gauge set could be slowly leaking too at the fittings and on the gauge set itself. I am not sure if you should expect vacuum to remain resident in the system overnight or with the change in temp and such and with the attrition of the gauge set potentially, you're looking more at what the system does say in 30 minutes from pulling vacuum. At this point, I am going to flush, vacuum again and re-shoot the system with dye and charge to spec then drive and run the system to see if it leaks, then if it does, black light it and hopefully it is not the evap. Any thoughts? :-)))

cmeseadoin on Mon May 19, 2008 9:45 AM User is offline

Thanks for the info Tim.....I'm going to look at costs for alldata. So, they do this by vehicle? Will look......

TRB on Mon May 19, 2008 10:36 AM User is offlineView users profile

Quote
Originally posted by: cmeseadoin
Thanks for the info Tim.....I'm going to look at costs for alldata. So, they do this by vehicle? Will look......

Yep, and it covers not only the A/C stuff but the brakes, motor and so on. So if you are even doing things on the side it's worth it. If I remember correctly the first purchase is $ 24.99 and then any purchases after that is $ 17.99 per year. Also if you use our link we get like $ 3.00 bucks for each purchase through the affiliate account. Cost is still the same if you use our link or not.


-------------------------
When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

cmeseadoin on Tue May 20, 2008 9:31 AM User is offline

Update: Pulled a vacuum on the S10 again for one hour when I got home from work yesterday, then recharged the system with about 32oz r134a and some UV dye. System is working very well and I am having the truck driven the a/c on for a while so as to circulate the refrigerant and the oil carrying the dye so that if it leaks, the oil will carry the dye out. She's cooling very well and so hopefully there will not be any further issues!

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