A/C help please....
Thread Starter
Team Owner
Joined: Jan 2000
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Kansas City Area Coordinator
St. Jude Donor '08-'09-'10-'11,'13
A/C help please....
Ran a static test, dead cold, sitting for 3 days, I got a 50 PSI on both high and low side
Back the C5 out fo the garage, shut down engine. Waited about 10 minutes, pulled a static of 80 psi on both high and low side.
Started engine, A/C full blast @ 2000 rpm.
Pulled a 120 low and a 170 high.
DIC code B0367h
51% humidity - ambient temp - 91°
I always thought the low side went down when running?
A/C worked fine last season.
Thoughts?
Back the C5 out fo the garage, shut down engine. Waited about 10 minutes, pulled a static of 80 psi on both high and low side.
Started engine, A/C full blast @ 2000 rpm.
Pulled a 120 low and a 170 high.
DIC code B0367h
51% humidity - ambient temp - 91°
I always thought the low side went down when running?
A/C worked fine last season.
Thoughts?
Le Mans Master
Joined: Nov 2005
Posts: 6,993
Likes: 25
My chart says 45-55psi @ 90 F
From another site:
How can I tell if the expansion valve is bad?
This has to be our least favorite item to diagnose. We've had expansion valves quit working while on the road and show no signs of problem back in the shop. What's worse, an expansion valve can stick closed, stick open, or hang somehwere in between.
Of all the bad expansion valves seen over the years, I think those that stick closed are most common. Those are the easy ones. Gauges will show very low suction side pressure along with lower than normal high side pressure. The low side may even draw into a vacuum. That's a big clue. Those that appear to be stuck closed may have inlet screens clogged with ground up desiccant particles. This will look like beach sand packed into the inlet.
It's common for a defective expansion valve to stick closed, however, the expansion valve can also stick open. This is indicated by higher than normal low side pressure, and slightly higher than normal high side pressure. To some, this might appear as a weak compressor or slightly overcharged system.
From another site:
How can I tell if the expansion valve is bad?
This has to be our least favorite item to diagnose. We've had expansion valves quit working while on the road and show no signs of problem back in the shop. What's worse, an expansion valve can stick closed, stick open, or hang somehwere in between.
Of all the bad expansion valves seen over the years, I think those that stick closed are most common. Those are the easy ones. Gauges will show very low suction side pressure along with lower than normal high side pressure. The low side may even draw into a vacuum. That's a big clue. Those that appear to be stuck closed may have inlet screens clogged with ground up desiccant particles. This will look like beach sand packed into the inlet.
It's common for a defective expansion valve to stick closed, however, the expansion valve can also stick open. This is indicated by higher than normal low side pressure, and slightly higher than normal high side pressure. To some, this might appear as a weak compressor or slightly overcharged system.
Last edited by dougbfresh; Jun 6, 2011 at 06:18 PM.
Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
For what its worth? It looks like both sides are off when running, the idle or static reading is probably ok. The low should be around 35 psi and the High should be around 187 -212 psi while running. The low side should be what you feel coming out of the vents or there abouts. You may want to vacuum the system and recharge it,(on the fender) along with some dye and see if there are any leaks. Again, I am not an expert, but am referring to an excellent article in my Vette mag. Hope this helps some.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The C5/C6 systems use a fixed orifice tube as the R-134 meter. It sounds like yours is clogged. Very common! It requires depressurizing and orifice tube replacement and system repair.
You have to figure out what clogged it... Sometimes its damaged compressor Teflon piston rings other times its system crud from poor repairs in the past or degraded hosed.
BC
You have to figure out what clogged it... Sometimes its damaged compressor Teflon piston rings other times its system crud from poor repairs in the past or degraded hosed.
BC
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Burning Brakes
Joined: Jun 2010
Posts: 1,014
Likes: 5
From: Rockwall TX
BC is right on the money there, had to do that to my car. One thing I noticed was when the compressor tried to run, it felt and sounded like it was bogged down if that makes sense. Just pulling on the engine.
Last edited by dmarkshark; Jun 7, 2011 at 09:09 AM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
OH,,,,
Before I forget,, if you do the work your self,, you will need, new O rings, Compressor oil, orifice tube and a new receiver dryer for the correct repair.. When repairs are done, the system will have to be vacuumed out and properly recharged.
BC
Before I forget,, if you do the work your self,, you will need, new O rings, Compressor oil, orifice tube and a new receiver dryer for the correct repair.. When repairs are done, the system will have to be vacuumed out and properly recharged.BC
Thread Starter
Team Owner
Joined: Jan 2000
Posts: 35,444
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Kansas City Area Coordinator
St. Jude Donor '08-'09-'10-'11,'13
Yep, I will do the work myself.
I've built several engines, restored a few cars but this is the first time I have cracked open an A/C.
Not afraid to try but dont want to FUBAR it either.
Anyone handle O-ring kits for this application?
I have access to the vacuum.
Anyway to tell prior to cracking it open if my compressor is shot?
I have Rocco's post on compressor replacement printed out.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thanks Bill,
Yep, I will do the work myself.
I've built several engines, restored a few cars but this is the first time I have cracked open an A/C.
Not afraid to try but dont want to FUBAR it either.
Anyone handle O-ring kits for this application?
I have access to the vacuum.
Anyway to tell prior to cracking it open if my compressor is shot?
I have Rocco's post on compressor replacement printed out.
Yep, I will do the work myself.
I've built several engines, restored a few cars but this is the first time I have cracked open an A/C.
Not afraid to try but dont want to FUBAR it either.
Anyone handle O-ring kits for this application?
I have access to the vacuum.
Anyway to tell prior to cracking it open if my compressor is shot?
I have Rocco's post on compressor replacement printed out.
I know you can contact Gene Culley for all the GM parts www.gmpartshouse.com
You can try NAPA as they have stuff like that.
Heres some cool AC post that I have collected:
- C5 AC System Service and Repairs: http://forums.corvetteforum.com/c5-g...post1570703001 ,,
Rocco’s post http://forums.corvetteforum.com/c5-t...post1571637102
- CJCVETTE, mcgilles How to repair HVAC ACTUATORS: http://forums.corvetteforum.com/c5-t...post1576657600 , http://forums.corvetteforum.com/c5-t...post1577408061
- C5 HVAC Repair vacuum line; http://forums.corvetteforum.com/c5-t...with-pics.html
Le Mans Master
Joined: Oct 2004
Posts: 9,369
Likes: 4
From: Zephyrhills, Florida
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13
after evac, a new orifice tube and drier will seem like a miracle has occured! As Bill says, don't forget the compressor oil
Thread Starter
Team Owner
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Kansas City Area Coordinator
St. Jude Donor '08-'09-'10-'11,'13
Since this is the wife’s daily driver and its getting close to 100° for the next few days I dropped in a can of R-134 with leak detector to get her by.
Was in a rush and didn’t get a gauge reading but the A/C is cranking very cold air.
Not sure for how long but should hold till the weekend when I get a chance to do a deep dive.
Was in a rush and didn’t get a gauge reading but the A/C is cranking very cold air.
Not sure for how long but should hold till the weekend when I get a chance to do a deep dive.
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
All i did was replace orfice tube $5 and add some compressor oil
Thanks Bill,
Yep, I will do the work myself.
I've built several engines, restored a few cars but this is the first time I have cracked open an A/C.
Not afraid to try but dont want to FUBAR it either.
Anyone handle O-ring kits for this application?
I have access to the vacuum.
Anyway to tell prior to cracking it open if my compressor is shot?
I have Rocco's post on compressor replacement printed out.
Yep, I will do the work myself.
I've built several engines, restored a few cars but this is the first time I have cracked open an A/C.
Not afraid to try but dont want to FUBAR it either.
Anyone handle O-ring kits for this application?
I have access to the vacuum.
Anyway to tell prior to cracking it open if my compressor is shot?
I have Rocco's post on compressor replacement printed out.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If its packed full of big hunks of Teflon ,, its time for a LOT bigger repairs and flushing the system.
REMEMBER! The system DOES NOT LIKE to be starved for oil! ADD the correct oil charge while its apart!
VACUUM the NON CONDENSIBLES (AIR) out and "PROPERLY" refill the system with the correct amount of r-134. Use the charge table in the service manual for the correct high and low side pressures vs humidity, temp and RPM. The system works better slightly undercharged rather than over charged believe it or not!!
BC
Thread Starter
Team Owner
Joined: Jan 2000
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Kansas City Area Coordinator
St. Jude Donor '08-'09-'10-'11,'13
Dumb question but would an "over charge" show a higher pressure?
My '03 GMC cools but not like I think it should. There were reports of the A/C units being over charged from the factory.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The chart is very exact in the set up conditions and outside conditions and the high and low pressures that your should see in the system.
If your going to service your own system, purchase the Gage manifolds and the service manuals.
The service manual set have saved me thousands of dollars!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Thread Starter
Team Owner
Joined: Jan 2000
Posts: 35,444
Likes: 0
Kansas City Area Coordinator
St. Jude Donor '08-'09-'10-'11,'13
The only way to know that status of your system is to use the FACTORY AC Service manual and compare the troubleshooting guide and pressure chart to the actual observed pressures.
The chart is very exact in the set up conditions and outside conditions and the high and low pressures that your should see in the system.
If your going to service your own system, purchase the Gage manifolds and the service manuals.
The service manual set have saved me thousands of dollars!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The chart is very exact in the set up conditions and outside conditions and the high and low pressures that your should see in the system.
If your going to service your own system, purchase the Gage manifolds and the service manuals.
The service manual set have saved me thousands of dollars!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I have the factory service manuals for the C5 and a set of gauges for R-134, but not manual for the GMC
Melting Slicks
Joined: Jul 2006
Posts: 2,332
Likes: 31
From: Silver Spring MD
I DID replace the Orfice Tube evacuated and recharged
You can extract and examine the orifice tube. If its just dirt and debris, you can just replace the tube, add oil, vacuum, recharge and move on .
If its packed full of big hunks of Teflon ,, its time for a LOT bigger repairs and flushing the system.
REMEMBER! The system DOES NOT LIKE to be starved for oil! ADD the correct oil charge while its apart! VACUUM the NON CONDENSIBLES (AIR) out and "PROPERLY" refill the system with the correct amount of r-134. Use the charge table in the service manual for the correct high and low side pressures vs humidity, temp and RPM. The system works better slightly undercharged rather than over charged believe it or not!!
BC
If its packed full of big hunks of Teflon ,, its time for a LOT bigger repairs and flushing the system.
REMEMBER! The system DOES NOT LIKE to be starved for oil! ADD the correct oil charge while its apart!
VACUUM the NON CONDENSIBLES (AIR) out and "PROPERLY" refill the system with the correct amount of r-134. Use the charge table in the service manual for the correct high and low side pressures vs humidity, temp and RPM. The system works better slightly undercharged rather than over charged believe it or not!!BC