C5 ac experts help!!
Thread Starter
Heel & Toe
Joined: Dec 2016
Posts: 15
Likes: 0
C5 ac experts help!!
Hi fellas, need a hand here. 98 c5 still blowing hot!
Dual zone with manual **** for passenger.
replaced all o-rings, orifice, drier, compressor, blew out lines and condenser when apart, replaced both blend door actuators. I can feel the new blend doors moving when I turn the temp up or down. pressures are a touch high I had 35/205 yesterday at 85 deg and 44% humidity. line is not very cold after orifice. pulled fuse 27 for longer than 1 minute. only hvac code left in inside temp sensor cause I still have interior panels off. that's only for auto I believe? I did notice there are 2 parts for orifice, but wouldn't the wrong orifice or a clog screw up my pressures?? I'm at a loss?? can't find any more info searching. tia!
Dual zone with manual **** for passenger.
replaced all o-rings, orifice, drier, compressor, blew out lines and condenser when apart, replaced both blend door actuators. I can feel the new blend doors moving when I turn the temp up or down. pressures are a touch high I had 35/205 yesterday at 85 deg and 44% humidity. line is not very cold after orifice. pulled fuse 27 for longer than 1 minute. only hvac code left in inside temp sensor cause I still have interior panels off. that's only for auto I believe? I did notice there are 2 parts for orifice, but wouldn't the wrong orifice or a clog screw up my pressures?? I'm at a loss?? can't find any more info searching. tia!
Last edited by averyinfullerton; May 2, 2025 at 02:25 PM.
Burning Brakes
Joined: Sep 2014
Posts: 776
Likes: 98
From: carroll ohio
mine blew hot after my guys recharged the system after a compressor kit install. I rebooted the system by removing the fuses from the pass footwell and followed the directions I got from this forum. cannot remember the way I did it but it worked. you'll have to search this forum to find how to do this. sounds like the blend door is not functioning the right way. hope this helps
Drifting
Joined: Jan 2008
Posts: 1,722
Likes: 138
From: Florida
St. Jude Donor '09
I had 35/205 yesterday at 85 deg and 44% humidity. line is not very cold after orifice. pulled fuse 27 for longer than 1 minute. only hvac code left in inside temp sensor cause I still have interior panels off. that's only for auto I believe? I did notice there are 2 parts for orifice, but wouldn't the wrong orifice or a clog screw up my pressures?? I'm at a loss?? can't find any more info searching. tia!
Thread Starter
Heel & Toe
Joined: Dec 2016
Posts: 15
Likes: 0
yes, I vacuumed the system 45 min, left closed for 1 hr, no leaks, added oil per compressor kit instructions, added refrigerant per fsm which same info as factory tag on coolant tank. 1.75 lbs i think, not near car rn. I mean it's possible some air got in? was thinking about changing the orifice to the one with the brass and re doing it all. Just looking for advice as I'm stumped.
Heel & Toe
Joined: Sep 2002
Posts: 22
Likes: 9
From: Abingdon MD
205 on the high side is not very high, in my opinion (not an expert)
Here's some numbers I got:
27/225, 38* at vent, ambient = 63* 48%, at idle
What rpm are you at?
The pressures should respond to revs. low side should dip down and high side should increase.
Try a fan in front of the car. If the vent temp goes down that could be low refrigerant. (I read you measured)
Does it cycle?
Here's some numbers I got:
27/225, 38* at vent, ambient = 63* 48%, at idle
What rpm are you at?
The pressures should respond to revs. low side should dip down and high side should increase.
Try a fan in front of the car. If the vent temp goes down that could be low refrigerant. (I read you measured)
Does it cycle?
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Advanced
Joined: Mar 2023
Posts: 82
Likes: 19
From: Cape Coral
The C5 Corvette uses a V7 variable displacement compressor, at lower RPM it has a larger displacement and at higher RPM it has a lower displacement to keep relatively constant pressures. It should be cold even at low RPM. Also the clutch stays engaged as long as the AC is turned on so you will only hear a click when you turn on the AC.
Thread Starter
Heel & Toe
Joined: Dec 2016
Posts: 15
Likes: 0
update.. got it put back together put a heater bypass in, drove it and yes the air coming out is cool, but not cold. thinking ill take it and get it tucked down and refilled at a shop with a machine and hopefully be done with it with a correct charge. maybe I got some air, or moisture in it?
Uneducated autodidact
Joined: Feb 2001
Posts: 5,413
Likes: 252
From: West of the Sabine, Texas
I'm curious, what prompted you to start this project? Did your compressor fail, or the system wasn't cooling at all, or was it not cooling adequately? Oh, and thanks for the update 
.
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Instructor
Joined: Feb 2014
Posts: 123
Likes: 70
Check your valve cores. When I had to change my condenser last month I put in some new valve cores. But when I closed the gauge set off they actually tuned the cores loose about 1/2 turn. I still had decent pressure when I hooked up but no cool air. Ended up having to discharge the system and vacuum again then charge it back up. This time I made sure to tighten the cores back up when I took the lines off. Each core turned 1/4 turn.
Thread Starter
Heel & Toe
Joined: Dec 2016
Posts: 15
Likes: 0
replaced both when I rebuilt the system. Definitely a thing, happened to my truck.
I dropped the drivetrain when I bought the car, torque tube came apart and locked the engine. got lucky and it was just the tube! did anything low while I was there.
I dropped the drivetrain when I bought the car, torque tube came apart and locked the engine. got lucky and it was just the tube! did anything low while I was there.
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,167
From: Dyer, IN
Did you use 12 oz cans? If so, did you deduct 1oz for full cans a 2 oz for hoses?
Thread Starter
Heel & Toe
Joined: Dec 2016
Posts: 15
Likes: 0
alright, heres where im at now, i discharged the system, and recharged it. using 1.63lbs as per the sticker. pressures were 35/350 so i shut it down. line was hot on low side. which indicates a blockage. im going to replace the orifice with the gm one with the brass piece in it. maybe i didnt clean the system out good enough.
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,167
From: Dyer, IN
alright, heres where im at now, i discharged the system, and recharged it. using 1.63lbs as per the sticker. pressures were 35/350 so i shut it down. line was hot on low side. which indicates a blockage. im going to replace the orifice with the gm one with the brass piece in it. maybe i didnt clean the system out good enough.