98 air conditioning
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
98 air conditioning
AC system completely replaced (original GM, non reman parts). Will only get fairly cold on highway but hardly even cool in traffic. Compressor replaced twice and orifice twice. High side reads correct, but low side stays at about 60lbs indicating possible blockage. But, can't find one. I did see an orifice available for this car that was forty two dollars, expensive but needed?
Instructor
Joined: Nov 2016
Posts: 186
Likes: 15
From: Elliot Lake Ontario, Canada
I'm not an auto a/c guy, but I am a refrigeration mechanic (mostly grocery stores). I would expect a restriction in the system at the oriface to cause low suction pressure, not high, unless the restriction is between the port where you are measuring pressure and the compressor. Is there a filter/drier between the low side pressure port and the compressor? If so I would suspect that. When I get a chance later today, I'll look at a drawing of the a/c system for clues.
Instructor
Joined: Nov 2016
Posts: 186
Likes: 15
From: Elliot Lake Ontario, Canada
I tried to find a diagram, found a couple but not much detail about the components. If your compressor is actually running, and your measuring high low side pressure, there either has to be a restriction of some sort between the pressure port where you're reading the pressure and the compressor, or the compressor has failed. I did find one reference to the accumulator referring to it as an "accumulator / drier", as I said, not unusual for a drier to plug up, but it looks from the diagrams I did find that the accumulator drier is up stream of the pressure port so that shouldn't be the problem. A good a/c tech should be able to identify a restriction quite easily if there is one, or a bad compressor. Sorry I wasn't more help, but without seeing it hands on so to speak, it's difficult
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
I'm not an auto a/c guy, but I am a refrigeration mechanic (mostly grocery stores). I would expect a restriction in the system at the oriface to cause low suction pressure, not high, unless the restriction is between the port where you are measuring pressure and the compressor. Is there a filter/drier between the low side pressure port and the compressor? If so I would suspect that. When I get a chance later today, I'll look at a drawing of the a/c system for clues.
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
NOT myself. I have an auto ac person doing the checking. He also did the installation of the entire system. I was and am there for all the work. Yes, he does have all the equipment. With every check he has pulled the vacuum down as far as could be done. We've added the right amount of freon, gone just a little more, and just a little less each time. Still can't get the low side below 60-61 lbs which keeps the vent (vents) temp no less than 64-65 degrees. Should be about 44-46 degrees. We have changed the orifice but not the dryer, which is new.
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
Thanks, but my ac guy has all of this on his diagnostics discs. We even put in a new radiator with double the capacity. Guess we might have to change the new dryer and the evaperator also. Other than that, we are baffled. Again, all parts are gm and not remans, though, that doesn't mean one or more aren't faulty.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Instructor
Joined: Nov 2016
Posts: 186
Likes: 15
From: Elliot Lake Ontario, Canada
I would still look between the pressure measuring port and the compressor. A restriction in the evaporator should cause low pressure, not high. When you figure it out, let us know, I'm curious
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
I guess we're going to have to start changing other new parts, like the evaporator. The compressor has been changed twice. Man, I was hoping this had happened to other vette owners who had replaced their entire ac system, and had an answer. When we get it working, I'll let you know.
Advanced
Joined: Jan 2014
Posts: 67
Likes: 10
Ac
I had a similar problem. Freeze you out on the highway and was mediocre at best in town. In my case the evaporator fins were mostly blocked by years of junk getting stuck in them.
In my case I was changing the radiator so I ordered a new evaporator and it now works much better. From your symptoms it almost has to be the evaporator since your gauge is off on the low side.
HTH,
Dan...
ps. I have a 98 and rebuilt my ac except for the evaporator. Kicked myself when I discovered the problem. Lived with it until radiator started leaking and did them both.
In my case I was changing the radiator so I ordered a new evaporator and it now works much better. From your symptoms it almost has to be the evaporator since your gauge is off on the low side.
HTH,
Dan...
ps. I have a 98 and rebuilt my ac except for the evaporator. Kicked myself when I discovered the problem. Lived with it until radiator started leaking and did them both.
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
I had a similar problem. Freeze you out on the highway and was mediocre at best in town. In my case the evaporator fins were mostly blocked by years of junk getting stuck in them.
In my case I was changing the radiator so I ordered a new evaporator and it now works much better. From your symptoms it almost has to be the evaporator since your gauge is off on the low side.
HTH,
Dan...
ps. I have a 98 and rebuilt my ac except for the evaporator. Kicked myself when I discovered the problem. Lived with it until radiator started leaking and did them both.
In my case I was changing the radiator so I ordered a new evaporator and it now works much better. From your symptoms it almost has to be the evaporator since your gauge is off on the low side.
HTH,
Dan...
ps. I have a 98 and rebuilt my ac except for the evaporator. Kicked myself when I discovered the problem. Lived with it until radiator started leaking and did them both.
Thread Starter
Instructor
Joined: May 2010
Posts: 101
Likes: 2
ac
Yes. We tracked the problem back to the evaporator. And yes, it's in dash, and yes, it's going to be expensive. Not only that, I broke the adjustment rod on driver side headlight assembly. Unless I can find something, that's going to be expensive. And yes, I'm still going to keep the car no matter.
Burning Brakes
Joined: Aug 2013
Posts: 1,071
Likes: 322
From: palm springs ca
Neal, cheyymans 77. I am going to start a thread and use your belt on pulley theory. Great and makes sense. Compressor leakes are a C2 problem. One caused by exactly what you pointed out about the pulley being off set by a over tightened belt. Off set causes 2 part seal to move on face as you said.
Thread will be NCRS.
Dom
Thread will be NCRS.
Dom
Race Director
Joined: Jan 2000
Posts: 10,327
Likes: 3,358
From: Central TX
C5 of Year Finalist (appearance mods) 2019
Neal, cheyymans 77. I am going to start a thread and use your belt on pulley theory. Great and makes sense. Compressor leakes are a C2 problem. One caused by exactly what you pointed out about the pulley being off set by a over tightened belt. Off set causes 2 part seal to move on face as you said.
Thread will be NCRS.
Dom
Thread will be NCRS.
Dom
Administrator
Joined: Mar 2001
Posts: 367,766
Likes: 24,683
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
Closed and moved to C5 Tech.
Last edited by Vetteman Jack; Jun 21, 2020 at 01:28 AM.